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Tektronix 803A User's Manual

1. Figure 2 5 The Trigger Major Menu and Source Pop Up Menu Now that the Source pop up menu is displayed you can specify the internal clock trigger source C Step 8 Touch the Internal Clock selector in the pop up menu This selects Internal Clock as the trigger source Notice that the Source selector in the major menu now indicates Internal Clock Step 9 Touch Exit to remove the pop up menu Operating Basics Autoset CSA 803A User Manual Example 1 Displaying a Trace You now see a flat trace on the display However it does not show the interesting part of the trace To quickly show the desired data use the autoset feature The AUTOSET button located above the sampling heads just to the right of the major menu buttons see Figure 2 6 automatically sets the horizontal vertical and trigger parameters to display the desired portion of the trace The AUTOSET Button ACQUISITION nancom SEQUENCE A salaa Figure 2 6 AUTOSET Button Location C Step 10 Press the AUTOSET button above the sampling heads You will see several cycles of the calibrator signal on the display Example 1 Displaying a Trace Autoset Options You have used autoset to show several complete cycles of the calibrator signal The Instrument Options pop up menu of the Utility major menu controls autoset operation see Figure 2 7 2 ya rte art SE pal Autaset Opticns PESEE EE EE hanced
2. Self Test Diagnostics Extended Diagnostics Display Intensity 24 Display Persistence 25 08 Setting the Persistence Mode Normal cinararwnthuewse types etek Variable seciecuii ct Maury Wate Aas aN toads INNTE sic sdgevete duncan nes ates Color Grading ass ceunia ee eaces seers meee aoa oaeeer tee na ee zPoaereenetae eee ee oe eo RH soe erP osteo eee ee HHH Seer enue eee ee HHA TE ee eee eee ee oh ke gay eos eee oo ee ee ER HHH Oe eo oe ee eee eh yo ee vsvnnsn enszncvnennay Interpreting the Color Graded Display Changing Colors Limiting Acquisition Enhanced Accuracy 0 eceeeneeae Control of Automated Calibration Calibration Assistance Sampling Head Calibrations Typical Calibration Method Calibrating Gain Manually a ry ed H HRP Re Ne EEK ae neem nave n eer eee rene soe t eee eae tre eestewan ee ee ee ay Calibrating Blowby Compensation Manually Calibrating Offset Manually Calibrating TDR Amplitude Manuaily Adjusting Delay Adjust Manually Offset for Sampling Probes Eye Diagrams 0 0 cece eee aee Displaying an Eye Diagram Fast Fourier Transforms 0 000005 Defining an FFT Trace 0000 ee 2
3. ee n eeepc meeawee weet ez en enenee ye Side Effects of Averaging and Enveloping Baseline Correction ceeencee Example nniiced sc Secnr dat vine netees Calibrator lt lt cok ocei ariaa n Color Display 30ici se ewsw vad ieee bs coe Color Selection 00eesneeee Restoring Colors Reassigning Trace Colors Setting the Display Intensity Constellation Diagrams Displaying a Constellation Diagram Header etree ee owe en oaee Ce ee CC ee fae tee ewe eae eee eee ee ee ete earnest eee joe tate eee oh eee ee oo eee etot ene eee ee oe ee seo 2 73 2 75 2 76 2 78 2 81 2 85 2 89 2 92 2 93 3 1 3 1 3 2 3 3 3 5 3 7 3 9 3 10 3 10 3 11 3 13 3 14 3 15 3 15 3 16 3 16 3 17 3 17 3 19 3 21 3 21 3 22 3 23 3 23 3 25 3 25 Table of Contents vi CBOE yi a a a OE ER KR Cursor Operation 0 c cess eee eee Selecting Cursor Types Cursor Calibration Removing Cursors 005 Additional Cursor Facts Cursor Examples 00502008 Measuring Trace Amplitude zeae meee AHR AHH ARE HT HE tun szazsuzaxzxnaszyanap ee Ce unrar anwe ee on ee sr dnabdhsoanl nszxasxanngenn ayota n A Ce ee ey Measuring Time Between Points On Different Traces Diagnostics ii dieu dae aeeweea sal news Power On Diagnostics
4. Figure 3 6 Front Panel Autoset Button 0 ee ees Figure 3 7 The Instrument Options Pop up Menu Figure 3 8 The Acquire Desc Pop up Menu 60 Figure 3 9 Location of the CALIBRATOR and INTERNAL CLOCK Outputs 2 0 5 oo oie pseu waa eee Catt ee taveko deacon Figure 3 10 The Color Pop up Menu 0 000 e eee e eee e ees Figure 3 11 Adjusting the Main Position 0 6 0 0 seca Figure 3 12 How the Expanded Waveforms Should Appear Figure 3 13 The Display After Selecting the XY Display Mode Figure 3 14 The Cursors Major Menu and Cursor Type POOAID Men chris 35 ok ey detonator ale tA Figure 3 15 The Set Zero Pop up Menu 2 eee eee eee eee Figure 3 16 The Self Test Pop up Menu in the Utility2 Major WGN ooon rerne aE E E E Sue vette wate akan abot ey Figure 3 17 The Extended Diagnostic Pop up Menu in the Utiity2 Maior Menu 62 asia nee ed uddasg eine esa hen vase de Figure 3 18 The Top Portion of the Extended Diagnostics Menu Figure 3 19 The instrument Options Pop up Menu Figure 3 20 The Persist Histograms Pop up Menu 2 56 2 57 2 59 2 61 2 64 2 65 2 67 2 69 2 70 2 71 2 75 2 76 2 78 2 81 2 82 2 85 2 87 2 89 2 90 2 91 3 1 3 3 3 4 3 5 3 9 3 10 3 15 3 19 3 22 3 26 3 27 3 28 3 30 3 31 3 37 3 38 3 38 3 41 3 43 xiv Contents CSA 803A User Manual Figure 3 21 Figure 3 22
5. 0 0c cece eee e eens 3 184 Displaying Time and Date with Stored Traces 3 185 System Identification ccccceceesceseeessceeeeeneesonas 3 187 TDR crenta tie CEE cer Owe eee aae Oe ee Pea se Rian ea ede es 3 189 TDR Step Generation ooo560 2nd eo pees sates ieee cake 3 189 Operation Into a Short Circuit 2 0 kee ee 3 190 Operation Into a 50 Q Load ssc sev thee taawiiaede cies 3 190 Operation Into an Open Circuit 2 0 eee eee 3 190 Baseline Conrecuon 2 ecirme vai sesai evans aha teees aes 3 191 Example Taking TDR Measurements 0c0ece een eaes 3 192 Changing Graticule Units for TDR 2 2265 3 193 Example Differential and Common Mode TDR 3 196 TDT Measurements 345 00 ssewiseig ben wene 5 ese ase ceed ved 3 199 More About TDR Measurements 000cee eee eeee 3 200 WIMG ONG Date ocine 5k eis cca lias aiete vee EE EAEAN 3 201 Displaying Time and Date with Stored Traces 4 3 202 Trace Definition and Management 2 e0ceeceeeaes 3 203 Defining New Traces 00 cece cece nee ae ee eeees 3 204 Defining Traces Using the DefTralcon 0 0 ee 3 204 Using Trace Functions in Trace Expressions 3 206 Defining Traces Using the Sampling Head Channel BO ceri rE tee ties tae ore ae EE as EE di aa 3 207 Trace Numbers j cc05occcswiee esi tesa des ee aceue ste eswnes 3 207 Selecting Traces i3 0655 boc dee vee eee bos REN eee a
6. 3 The smallest value that has a non zero point count is the minimum value 4 Determine the median value halfway between the maximum and mini mum values 5 Examine the point counts between the median value and the maximum value to find the largest point count If this point count is greater than or equal to twice the second largest point count the value associated with the point count is the topline If the largest point count is not twice the second largest point count then the maximum value is used as the topline 6 Examine the point counts between the median value and the minimum value to find the largest point count If this point count is greater than or equal to twice the second largest point count the value associated with the point count is the baseline If the largest point count is not twice the second largest point count then the minimum value is used as the baseline The Alternate method of determining topline and baseline is as follows 1 Smooth the raw waveform data 2 Differentiate the smoothed waveform data 3 Smooth the differentiated data 4 Search the smoothed differentiated data for the largest negative and positive peaks The peaks must be equal to at least 30 of the peak to peak amplitude to qualify as valid Appendices Appendix D Algorithms 5 Determine the 30 value of the largest valid topline and largest valid baseline peak 6 Search the smoothed differentiated data for crossin
7. 3 182 Reference Stored Traces Recalling Stored Once a trace is stored you can use it when creating a trace expression To Traces create a trace that displays a stored trace touch the Def Tra icon then in _ the pop up menu touch the Stored Traces selector the selector for the stored trace you want to display and the Enter Desc selector The Recall Trace pop up menu provides a simpler way to do the same thing Press the Store Recall major menu button and touch the Recall Trace selector to display the pop up menu In the pop up menu touch the selector for the stored trace you want to display See Figure 3 86 Figure 3 86 The Recall Trace Pop up Menu CSA 803A User Manual 3 183 Stored Traces Deleting Stored You can delete stored traces by using the Delete Traces pop up menu in Traces the Store Recali major menu This pop up menu may also be used to delete displayed traces See Figure 3 87 In the Delete Traces pop up menu touch the selectors for the displayed and stored traces you want to delete The traces are not deleted until you touch the Delete Selected Traces selector You may select several traces to be deleted before touching the Delete Selected Traces selector As you select traces to delete their selectors highlight to tell you they will be de leted If you touch a trace selector by accident touch it again to remove the highlighting If you want to delete all the displayed and stored traces touch the All Trac
8. CSA 803A User Manual Cursor Accuracy Considerations Table of Contents Ce ee Example 7 Taking Comparison Measurements Using a Reference Trace 5 Setting X Axis Units to Meters Feet or Inches Using the Reference Value ae eM ER RARER Example 8 Comparing Traces to Stored Traces Example 9 Creating a Histogram Display Example 10 Taking TDR Measurements Changing Graticule Units for TDR Measuring Distance with TDR Acquisition 20 cece eee ee een eens How Traces are Acquired Determining the Sample Interval Controlling Acquisition Clearing Traces ccccnensneess Audio Feedback cccccueeecnaeee AutosSet esis ons 5 earns See cw ekiclan tek Undoing an Autoset 2 2005 Autoset Options Standard Mask Autoset Averaging and Enveloping teereseer eases e ee eee eae Pe rnant ee eR R ARNE RRR He sae ev ce eaesc eee eee ee teen pte etereev sae eee cee eee Ce ee ee 2 eee eae eee eee eh THER HH HE nent need ete te tee ese coe Sot OR EE Co eee eR E MR EN sees we awe ezrweeezreseneasenes ee eee ewe eer up oae he SHH HRN HEE Defining an Averaged or Enveloped Trace Terminating Averaging or Enveloping 0 0c 0eeeeee Record Count cccueweccneces Limiting Acquisition
9. CSA 803A User Manual 1 9 Introduction Getting Started At a Glance This part of the manual presents general operating instructions and a road map of the menu system All menus are shown in this section Once you find a menu of interest you will be directed to the page in the Reference section that discusses that feature The Operating Basics section provides several examples on using the instrument Complete reference information is contained in the Reference section Front Panel and Sampling Heads The major menu butions tet you select which of the major menus appears at the bottom of the display See page 1 16 The display SHOWS the mmmm mmemennmatm traces and the menus which you touch to activate See page 1 13 The Touch Panel On Off button lets you turn off the touch panel so that you can point to the display without inadvertently making menu selections Antistatic Connector The two knobs control many functions of the instrument You set the knobs to control specific functions when you make menu selections or touch icons Using the knobs is described on page 1 15 The ACQUISITION button stops and starts trace acquisition see page 3 3 The AUTOSET button quickly sets the instrument parameters for a trace display see page 3 9 The HARDCOPY button prints a copy of the display see page 3 89 The SEQUENCE SETTINGS button lets you cycie through pre set instrument settings se
10. Example 2 Managing Multiple Traces The Graticules selector can create a dual graticule display see Figure 2 20 You can place traces on either graticule C Step 29 Press the WAVEFORM button to display the Waveform major menu C Step 30 Touch the Graticules selector in the major menu and touch Create Second Graticule in the pop up menu see Figure 2 19 The selected trace appears on the graticule with the horizontal lt gt and vertical icons this is called the active graticule If you select a trace on the other graticule it will make that graticule the active graticule r Step 31 Touch the Lower Graticule selector of the major menu it was Graticules Touch Move Trace to Other Graticule and observe the selected trace move to the other graticule Cl Step 32 Touch the Upper Graticule selector of the major menu it was Lower Graticule Touch Reduce to One Graticule Figure 2 19 The Graticules Pop Up Menu 2 27 Multiple Traces ing Manag x K Example 2 ifs x ve ui iR LD A Dual Graticule Display Figure 2 20 Operating Basics 2 28 Example 2 Managing Multiple Traces Removing Traces C Step 33 Below the knob labels touch the Remove Clir Trace n selec tor and then Remove Trace n in the pop up menu This will remove one of your traces leaving one on the display You could remove the remaining trace with Remove Clr Trace n agai
11. In addition to the annotation lines the portion of the trace that is used by the CSA 803A to determine the measurement value is highlighted when in Normal display mode or marked by dashed vertical lines in other display modes Figure 3 69 shows a typical pop up menu for an individual measurement along with the annotation lines and the highlighted portion of the trace Many of the selectors in the measurement pop up menu set the knobs to adjust the measurement parameters As you turn the knob the annotation lines move to reflect the new value of the measurement parameter For example in the software Frequency pop up menu the Left Limit Right Limit Mesial and S N Ratio selectors set the knobs to those measure ment parameters The dotted line style of the annotation lines is repeated in the relevant pa rameter selector in the pop up menu for the individual measurement When you remove the measurement pop up menu by touching its selector in the major menu area the annotation lines remain on the display The knob settings remain also so you can set the knobs in the pop up menu remove the pop up menu from the display and adjust the measurement parameter with the annotation lines on the trace NOTE You can remove the annotation lines completely by pressing the MEASURE major menu button 3 149 Measurements 413 Emy Left Limit Measurement Parameter Selector Left Limit Annotation Line Figure 3 69 A
12. Keypad Menu for that parameter The Pan Zoom selector lets you expand any part of a trace using horizontal magnification See page 3 109 When the knobs are assigned to vertical size and offset this selector may change to provide more vertical control See page 3 219 CSA 803A User Manual At a Glance Major Menu Buttons WAVEFORM TRIGGER MEASURE DISPLAY MODES STORE RECALL UTILITY Ot iru St Eee rene NECK EEEIEE OESTE EEEE EETA The Waveform major menu controls trace definition acquisition and the sampling heads See page 1 18 An alternate form of the Waveform major menu the Trace Status menu can be displayed using the More selector in the Waveform major menu See page 1 18 The Trigger major menu controls triggering See page 1 20 The Measure major menu controls the automatic measurement system See page 1 21 The Display Modes major menu controis display persistence histograms and mask testing See page 1 22 The Store Recali major menu controls storage and recall of trace data and instrument settings See page 1 23 1 16 Getting Started WAVEFORM TRIGGER MEASURE DISPLAY MODES STORE RECALL UTILITY CSA 803A User Manual Ata Glance The Utility major menu controls general instrument parameters such as display colors GPIB and RS 232 C settings and hardcopy parameters See page
13. Table 3 3 Delay Compensate Comparison Side Effect Increases system throughput May allow time coincidence slightly Compensates for drift in des kew adjustment between sampling heads of different sampling heads to drift over time and temper ature Slows system throughput slightly Reference Calibration Assistance CSA 803A User Manual Enhanced Accuracy The easiest way to calibrate the sampling heads is to use the Calibrate All selector to perform all the calibration adjustments for a single sampling head channel at once The CSA 803A prompts you to make the signal connec tions that are needed to calibrate automatically See Figure 3 23 Figure 3 23 The Calibrate All Pop up Menu You should first decide which sampling head channel you want to use as the reference channel for delay adjust The delay adjustment of the other heads will be calibrated to match the time position of this head Select the refer ence channel using the selectors in the Selected Channel section of the Calibrate All pop up menu Then touch the Measure Reference Channel selector and follow the displayed directions to connect the calibrator output to the selected channel Touch the Proceed selector to measure that channel NOTE With the Calibrate All pop up menu you must first establish the reference channel before you can calibrate any channels 3 51 Enhanced Accuracy 3 52 Once the reference channel is cal
14. s n DWO m 0 forn lt s H Smooth n 4 Swen me aAaAaw stl forn s The shifted mode trace only uses points that occur before the correspond ing point Thus the only points that are assumed occur before the trace not after Appendix D Algorithms Software Measurements Measurements are taken using the measurement parameters You can directly set many the measurement parameters or you can specify that some are to be determined automatically by the CSA 803A It is common to have the CSA 803A dynamically measure topline and baseline You specify automatic topline and baseline positioning by turning tracking on in the individual measurement pop up menus The mesial level when topline and baseline are automatically positioned by tracking is calculated mesial m 100 x topline baseline baseline where m is the percentage of topline to baseline height to use for mesial level Proximal distal and reference levels are calculated similarly from perceniage levels These percentage levels are set using the knobs When you use tracking the topline and baseline are determined either from the IEEE histogram method or from an alternate method The IEEE method of determining topline and baseline is as follows 1 Create a histogram of the trace data points For each possible vertical value count the number of data points having that value 2 The largest vaiue that has a non zero point count is the maximum value
15. 2 68 First you will use the cursors to determine the amplitude of the calibrator signal This introduces the use of cursors on a single trace You will then use cursors to measure the delay between two different traces The recommended way of using cursors is to first display the trace s and then invoke the cursors to take the measurement NOTE Always display the traces before invoking the cursors You invoke the cursors by touching the Cursors icon located above the graticule This icon acts like most icons in that it assigns the knobs in this case to control the cursor positions However the Cursors icon is unique in that it behaves much like a major menu button It replaces the major menu with the special Cursors major menu and highlights the Cursors icon instead of lighting any major menu button See Figure 2 42 The Cursors major menu has selectors for Cursor Type Set Zero and Exit The remainder of the major menu area displays the cursor positions and distance between cursors You can select four types of cursors Vertical Bars which you move with the knobs to the desired horizontal position The major menu shows the positions of the cursors and the distance between them in X units Also if the X units are seconds the inverse of the distance between the cursors is shown When the cursors are positioned at the beginning and end of a period this represents frequency m Horizontal Bars which you move with the knob
16. Cursors Cursor Operation Before you use cursors display the trace s that you want to measure The trace should be selected highlighted For split dot cursors either trace may be the selected one To invoke the Cursor major menu touch the Cursors icon located above the graticule with the selected trace This icon operates like one of the menu buttons at the right of the screen it has its own major menu When the Cursor menu is displayed none of the lights of the major menu buttons are lighted NOTE Establish all trace displays before turning on the cursors When you touch the Cursors icon the CSA 803A displays the cursors and their readouts Whenever you touch the Cursors icon the knobs are as signed to adjust cursor positions The Cursors major menu has three selectors Cursor Type Set Zero and Exit The rest of the major menu area shows the data readouts associated with the displayed cursors See Figure 3 14 NOTE The Cursors icon functions much like a major menu button te ee a NT rare ra Figure 3 14 The Cursors Major Menu and Cursor Type Pop up Menu 3 30 Reference CSA 803A User Manual Cursors Selecting Cursor Types At the top of the Cursor Type pop up menu you can select from four cursor types If you select Vertical Bars Horizontal Bars or Paired Dots the CSA 803A removes the pop up menu and shows the selected cursors The knobs control the cursor positions lf you sel
17. There are two types of SMA compatibie connectors on the CSA 803A a Standard SMA connectors with plastic insulating material between the center lead and the outer shield An example is the trigger INPUT con nector m High precision APC 3 5 connectors which have air insulation between the center lead and outer shield Examples inciude the input connectors on some of the sampling heads The APC 3 5 connectors are of closer mechanical tolerance than the stan dard SMA connector Attaching a worn or damaged SMA cable to an APC 3 5 connector may damage the APC 3 5 connector Higher bandwidth sampling heads may use other connectors that are not SMA compatible Consult your sampling head manual for more information Electrostatic Discharge The input diodes used in the sampling heads are susceptible to damage from overdrive signal or DC voltages and from electrostatic discharge Never apply a voltage outside the range printed on the front of the sampling head Operate the instrument only in a static controlied environment camo Applying a voltage outside the range printed on the sampling head can result in damage Static electricity is also a hazard Appendix C Safety Packaging for Shipment If you ship the CSA 803A pack it in the original shipping carton and packing material lf the original packing material is unavailable package the instru ment as follows O Step 1 Obtain a corrugated cardboard shipping carton wi
18. User Manual Tektronix CSA 8034 Communications Signal Analyzer Please bate for r eaer information at the rear a of this monna hg ni First Printing March 1993 7 instrument Serial Numbers Each instrument manufactured by Tektronix has a serial number on a panel insert or tag or stamped onthe chassis The first letter in the serial number designates the country of manufacture The last five digits of the serial number are assigned sequentially and are unique to each instrument Those mahuiaeturediin the United States have six unique digits The country of manufacture is identified as follows BO10000 Tektronix Inc Beaverton Oregon USA E200000 Tektronix United Kingdom Ltd London J300000 Sony Tektronix Japan nae H700000 Tektronix Holland NV Heerenveen The Netherlands Instruments manufactured for Tektronix by external vendors outside the United Siete bee assigned a two digit alpha code to identify the country of manufacture e g JP for Japan HR Tor Honig RONG We for Israel etc Tektronix Inc PO Box 500 Beaverton OR 97077 Printed in U S A Copyright Tektronix Inc 1993 All rights reserved Tektronix product ar covered by U S and foreign patents issued and pending The following are registered agomarki TONN TEK TEKPROBE and SCOPE MOBILE Ro WARRANTY ena Tektronix warrants that this product will be free from defects in materials and workmanship for a period of one 1
19. acters from Upper Case Lower Case Numbers which includes most punctuation Graphics mathematical symbols and more Greek the Greek alphabet and Other characters from non English alphabets Back Space lets you correct errors Exit removes the pop up menu 1 Step 25 Use the keyboard selectors to type in your own label for example CAL O Step 26 Touch the selector for Trace 2 Type in a label as you did for the first trace Finish by touching the Exit selector Once a label is established it moves with the trace You can control the position of the label relative to the trace The Position selector in the Label ing pop up menu to assigns the knobs to set the position of the label Trace labels will always stay on the graticule If the position or the movement of the trace would take a label off the display the edge of the graticule limits the movement of the label 0O Step 27 Touch the Labeling selector in the major menu area and touch the Position selector in the pop up menu C Step 28 Use the knobs to position the labels horizontally and vertically To select the label to move simply touch it as you wouid touch a trace to select it Note that each label is the color of its associated trace When you touch a label you select that trace 2 25 Example 2 Managing Multiple Traces Figure 2 18 The Labeling Pop Up Menu 2 26 Operating Basics Displaying Dual Graticules CSA 803A User Manual
20. ize then touch Initialize again C Step 2 Connect the CALIBRATOR output to any sampling head input using an SMA cable C Step 3 Press the sampling head SELECT CHANNEL button for the channel you are using L Step 4 Select the internal clock trigger source press the TRIGGER button touch the Source selector in the major menu and touch the internal Clock selector in the pop up menu C Step 5 Press the AUTOSET button 3 19 Calibrator 3 20 Reference Color Selection CSA 803A User Manual Color Display Specific colors are assigned to the items on the display The background graticule and selectors and cursors and measurement annotations are displayed in distinct colors for easy identification In addition there are up to four colors for traces and an additional color for window traces The four trace colors are assigned automatically to traces as the traces are defined When a window trace is defined it is displayed in the window trace color When you select a trace its color brightens You can modify the display colors to suit your preferences using the Color pop up menu in the Utility major menu See Figure 3 10 You can change the colors displayed and the overall intensity of the display You can also reassign the color of the selected trace to any of the four trace colors or window trace color The upper section of the Color pop up menu has a selector for each display color Next to each selector is a
21. lets you select between two types of message termina tions All message terminations assert the EOI End Or Identify signal in the interface You can choose to have the CSA 803A recognize a Line Feed LF character as a message terminator in addition to EOI by setting the Terminator selector to EOI LF The CSA 803A will then append a Line Feed character to the end of all messages Set the Termi nator selector to EOI to have only the EOI line recognized as a message terminator GPIB Debug lets you turn the debugging feature On or Off When you turn debug on the CSA 803A displays each command from the GPIB controller as it is executed The messages appear at the top of the display Debug off is the normal mode of operation Set debug on if you need to watch the result of each CSA 803A command of a controlling program running in the GPIB controller When debug mode is on it slows the GPIB interface throughput significantly 3 87 GPIB Parameters 3 82 Reference Graticules The grid on the display where traces appear is called a graticule The grati cule axis labels show you the horizontal and vertical scale factors of the selected trace most often expressed in time per division and voltage per division See Figure 3 41 Top Edge Value Vertical Scale l T 4 Bottom Edge Value Left Edge Value Horizontal Scale Right Edge Value Factor Figure 3 41 Graticule with Trace if a graticule shows two or mor
22. 17pm 3 2 58 0gBizZns loevdiv 50 0p1pi ns Figure 2 30 Averaged and Normal Traces 2 46 Operating Basics CSA 803A User Manual Example 4 Using Signal Processing Cl Step 13 Touch Acquire Desc in the major menu and Average N in the pop up menu to turn off averaging Notice that the trace expression in the Vertical Desc selector has removed the average function specifica tion This is an example of averaging Enveloping is done similarly using Enve lope N Set EnvN and Envelope Complete selectors Both averaging and enveloping can be done simultaneously To do both you must enter the trace expression from the DefTra or Vertical Desc pop up menus No shortcut is available from the Acquire Desc pop up menu 2 47 Example 4 Using Signal Processing Variable Persistence 2 48 Another method of observing trace noise is using variable persistence available through the Display Modes major menu This leaves earlier trace data on the display for a specified period of time as new data values are added building a recent history of displayed trace points C Step 14 Press the DISPLAY MODES button in the MENUS column to display the Display Modes major menu Select Persist Histograms in the major menu area see Figure 2 31 Cj Step 15 Select Variable in the pop up menu and select Exit to remove the pop up menu The Infinite selector in the Persist Histograms pop up menu selects infinite persistence a dis
23. 2 86 Operating Basics CSA 803A User Manual Example 8 Comparing Traces to Stored Traces C Step 11 Create a difference trace by touching the DefTra icon then touch 1 or whatever channel number you are using under Trace Functions Stored Traces STO1 and Enter Desc C Step 12 Touch the vertical icon and adjust the top knob to set the vertical size of the trace to 50 mV div the vertica size of the stored trace The difference trace should be close to a flat trace because the signal you are comparing is identical to the source of the saved trace except for noise This setup is useful in cases where you are tuning a circuit to a known standard of performance First you save the desired signal trace from a circuit of known performance then you use the difference trace to observe other circuit samples These circuits can then be dynamicaily tuned to the same performance To accurately quantify the signal variation from a straight line you can use the RMS measurement C Step 13 Press the MEASURE button and touch Measurements RMS and Exit To tune a circuit you could make adjustments to get the smallest RMS measurement instead of simply trying for the flattest trace 2 83 Example 8 Comparing Traces to Stored Traces 2 84 Operating Basics Example 8 Comparing Traces to Stored Traces This exampie demonstrates how to store a trace that is a snapshot of a particular moment and how to u
24. 24tiwetiitox tsi dawyevou ye lees 3 206 Table B 1 CSA 803A Vertical System Specifications B 1 Table B 2 CSA 803A Time Base Specifications B 2 Table B 3 CSA 803A Input and Output Specifications B 3 Table B 4 CSA 803A Trigger Specifications 0 B 4 Table B 5 CSA 803A Display Specifications 4 B 5 Table B 6 CSA 803A AC Line Power Specifications B 5 Table B 7 CSA 803A Environmental Specifications B 6 Table B 8 CSA 803 Vertical System Specifications B 7 Table B 9 CSA 803 Time Base Specifications B 8 Table B 10 CSA 803 Input and Output Specifications B 8 Table B 11 CSA 803 Trigger Specifications 4 4 B 9 Table B 12 CSA 803 Display Specifications 005 B 10 Table B 13 CSA 803 AC Line Power Specifications B 10 Table B 14 CSA 803 Environmental Specifications B 11 Table D 1 Filter Characteristics of FFT Windowing Functions D 5 Table D 2 Values of icoeff for FFT Windowing Functions D 16 Table D 3 Values of wcoeff and m for FFT Windowing Functions D 22 xix Tables XX Contents CSA 803A Description CSA 803A User Manual Introduction This section describes the safety precautions power and signal connec tions and procedures you should follow when you install the CSA 803A it then provides
25. 25 points div 25 points div 50 pixels div 25 pixels div B 1 Appendix B Specifications Table B 2 CSA 803A Time Base Specifications Characteristic internal reference clock Sample rate Record length Sweep rate resolution Record duration Maximum sweep rate 512 point record 1024 point record 2048 point record 4096 point record 5120 point record Time interval measurement accuracy Specification Crystal controlled oscillator 200 kHz maximum User selectable 512 1024 2048 4096 or 5120 points 1 2 5 steps or 1 ps div increments 10 ps to 50 ms 1 ps div 1 ps div 2 ps div 5 ps div 5 ps div 8 ps 0 01 of selected delay 0 001 of position guaranteed 4 ps 0 004 of selected delay 0 0004 of position typical Appendices Appendix B Specifications Table B 3 CSA 803A Input and Output Specifications Characteristic Specification Touch panel Infrared beam touchable array 22 rows of 11 columns Knobs 2 general purpose knobs set by user to desired function Calibrator output step Voltage 500 mV open circuit or 250 mV into 50 Q Frequency Approximately 100 kHz 50 kHz if divide by two mode selected Risetime Approximately 250 ps into 50 O Internal clock output Synchronized with TDR and calibrator output Voltage Positive pulse from 0 to 2 0 V Source impedance 50 Q Repetition rate Approximately 100 kHz 50 kHz if divide b
26. Figure 3 65 Figure 3 66 Figure 3 67 RMS Selected Figure 3 68 Figure 3 69 Figure 3 70 Menu Figure 3 71 Figure 3 72 Figure 3 73 Figure 3 74 5120 bottom Figure 3 75 Figure 3 76 Figure 3 77 Figure 3 78 Figure 3 79 Figure 3 80 Figure 3 81 Figure 3 82 Figure 3 83 Figure 3 84 Figure 3 85 Figure 3 86 Figure 3 87 Figure 3 88 Figure 3 89 Figure 3 90 Figure 3 91 Figure 3 92 Figure 3 93 Figure 3 94 Figure 3 95 Figure 3 96 Figure 3 97 Figure 3 98 Same Time Figure 3 99 Figure 3 100 The Deffra Pop up Menu Figure 3 101 The Trace Status Menu xvi a Creating a User Mask How Points are Connected in a User Mask Mask Count Readout Using Stop N Wims Measure Major Menu Measurements Pop up Menu with Frequency and es SRR oe he Ce szsyynsnn gt sossnasnsscunaceare Ce ennustan asvnaaksnasuant aonnarsensasrevaknzanyvoosnar aano Ce Compare amp References Pop up Menu A Typical Individual Measurement Pop up Menu Statistics in an Individual Measurement Pop up ee sa a ee Measurements Pop up Menu with Software Defaults Power Connector Fuse and Switches Front Panel ON STANDBY Switch Traces with Record Lengths of 512 top and ee ean ene n eu ee ove ee SS Sk ado ae ee eee ee pna The Horizontal Desc Pop up Menu Location of RS 232 C Connector The GPIB RS232C Pop up Menu Location of Sampling Head Compartments Sampling Head Control Panel SD 24 sh
27. NOTE Initialize All affects only the selected trace The right limit of the measurement is now set to 80 This change did not occur until you touched the Initialize All selector Had you been displaying other traces their parameters would have been unaffected by either the change to the defaults or by the Initialize All CSA 803A User Manual 2 61 Example 5 Taking Automated Measurements Measurement Modes Up to now the measurements you have been using have been software measurements However there are actually three measurement modes software mode hardware mode and statistics mode In software mode measurements are taken from the digitized trace data record the same data that forms the trace on the display In hardware mode measurements are taken from the analog signal output from the sampling head before it is digitized and assembled into a trace record The CSA 803A uses special timer circuits to take hardware measurements The advantage of hardware measurements is that they are performed faster than software measure ments In statistics mode measurements are taken from color graded waveform data and are based on histograms computed at the crossing levels You can use statistical measurements to measure random data such as eye diagrams You cannot take measurements in different modes on the same trace If you create two identical traces you can take hardware measurements on one and software measurements on the oth
28. S N ratio may be set to any value from 1 to 99 The reciprocal of the number is the fraction of the topline to baseline distance that the noise rejec tion band extends above and below the mesial line For a 1 V peak to peak sig nal S N ratio of 20 creates a noise re jection band 0 05 V above and 0 05 V below the mesial level The Prop Delay and phase measure ments shows the timing difference be tween two traces One of the traces is always the selected trace Second Trace lets you select to which trace the se lected trace is compared For Hardware Mode this can be a Saved Trace Description The direction the trace must pass through a reference level The 100 level on which proximal mesial distal and reference levels are based When tracking mode is Both or Topline the CSA 803A repeatedly deter mines the topline for itself and you can not adjust it When tracking mode is Off or Baseline you can set topline or you can have the CSA 803A set it once by touching the Setup selector and then adjust the values with the knobs With tracking set to Both the topline and baseline are repeatedly determined by the CSA 803A Tracking Off allows you to set topline and baseline When tracking is set to Baseline or Topline just the baseline or just the topline is tracked but not the other Tracking is only available if level mode is not absolute The number of times the signal must pass through a specified voltage level
29. Storing Mask Definitions Masks are saved with stored settings so you can save sets of masks by defining them then storing the instrument setting For the same reason any defined masks displayed on the screen will be overwritten whenever you recall a stored setting or initialize the CSA 803A NOTE For more details on Stored Settings see page 3 175 CSA 803A User Manual 3 127 Mask Testing 3 128 Modifying a User Mask To modify an existing user mask touch Mask Testing in the Display Modes major menu Select the mask you want to edit by touching the appropriate MaskN Definition selector and then touch Edit Mask Definition You can now add or delete points as described previously Creating a New Mask From a Standard Mask You can use one of the many standard masks as a basis for creating a new user mask To do this first select the desired standard mask from the Stan dard Masks pop up menu as described previously Then touch Mask Testing in the Display Modes major menu Each standard mask is com posed of two three or four mask components numbered Mask1 Mask2 Masks and Mask4 which you edit separately The Mask1 component is always at the top of the screen Mask2 is the second from the top and so on To edit the top mask component touch the Mask1 selector Then touch Edit Mask Defn The Mask Testing pop up menu disappears and the standard mask is displayed with the top mask component Mask1 high lighted with a blu
30. The message is accompanied by six groups of four characters You should note the accompanying information for your service person F 4 Appendices Glossary Acquisition The process of repeatediy sampling the signals coming through input channels and accumulating the samples into traces Active Graticule The graticule in a duai graticule display that shows the selected trace Annotation Lines that show the current measurement parameter settings in a visual way Autoset A means of letting the CSA 803A set itself to provide a stable and mean ingful display of a given trace Averaging Displaying a trace that is the combined result of several acquisitions thereby reducing apparent noise Axis Label There are three notations on each axis The first and last notation on each axis show the numeric value of the graticule edge not the edge of the displayed points which are slightly outside the graticule The center notation is the scale factor expressed in units per division Baseline Correction The process of maintaining the displayed vertical placement of a trace correcting for changes in the signal levels that would ordinarily move the trace up or down Channel A place to connect a signal or attach a network or transmission line to sampling heads Also the smallest component of a trace expression Channel Number The number assigned to a specific signa input connector The top channel of the left most sampling head com
31. before the measurement zone begins CSA 803A User Manual 3 155 Measurements Measurement The CSA 803A collects measurement statistics automatically when in either Statistics software or hardware mode Statistics are not collected in statistics mode You can set the N parameter to determine the number of individual measure menis on which the statistics are based Each measurement readout selector in the Measure major menu can be touched to bring up the pop up menu for the individual measurement This menu shows the number of measurement samples taken so far the mean and the standard deviation see Figure 3 70 The Set N selector sets the knobs to contro the N parameter Reported Statistics Figure 3 70 Statistics in an Individual Measurement Pop up Menu 3 156 Reference Changing Default Parameters CSA 803A User Manual Measurements Whenever you define a new trace the measurement parameters for that trace are initialized by copying them from a set of default parameters There is one set of default parameters for the CSA 803A You can set the default parameters to the values you want This does not change the measurement parameters of any existing traces but will set the initialized state of all new traces that you define You might want to change the default parameters if you are about to create a number of traces and take measurements from them knowing that they will all need the same measurement
32. ee Sen aer aren ewer adn eons soeseeeeoe eo ee eH EH so ett eb ee ee oe eee Ce nnenwnunneonodntao ee E EE r Er E r Defining an FFT Display Using the DefTra Pop up Menu Defining an FFT Display Using the FFTmag and FFTpha ICONS sor ca Seawidt eG ORDA Amplitude Resolution Frequency Range and Resolution Changing Horizontal and Vertical Size Ce ee ee 2 te tke eo ete ewe toe see aes ee ee 2 ecstveet eoetreasegonerenanee 3 29 3 30 3 31 3 31 3 32 3 32 3 33 3 33 3 33 3 35 3 36 3 37 3 38 3 41 3 43 3 44 3 44 3 44 3 44 3 44 3 45 3 46 3 47 3 49 3 50 3 51 3 53 3 54 3 56 3 57 3 57 3 58 3 58 3 60 3 61 3 61 3 65 3 66 3 66 3 67 3 68 3 68 3 69 Contents Table of Contents FET Scaling 2522226 eeeaeek cha eawreG ae Sextet enk esa waaneaes 3 70 Aliasing iostopacdcawhtce scars ANE EENE Ea 3 71 Using Cursors to Make Measurements 2 0000 3 72 FFT Windowing Functions e sesssssorsenssuuunusras 3 74 The Rectangular Window 0 0 c eee e eee anno 3 74 The Triangular WINKOW 25 esis hore s ben bene Seo Shan 3 75 The Blackman Window 0 000 cece cen e eee eens 3 76 The Blackman Harris Window 00 cece eee ee eee 3 76 The Hanning Window spose nb tao ae i ea ane wen Seah aen eo ad 3 77 The Hamming WINdOW ti cbvcadwares a eet eeen a Noakes 3 78 GPIB Parameters uuuassananrusesusransnunsrsssrusenso 3 79 GPIB C
33. gered and therefore is not showing on the display placing dot cursors on it will show vertical bars This is because without trace data there is no known vertical position for the dot a When atrace is scaled in rho and the cursor type is dots or Horizontal Bars ohms Q and ohmsx2 Ox2 values will also be displayed for the cursor Reference Cursor Examples CSA 803A User Manual Cursors Measuring Trace Amplitude The following procedure shows how to use cursors to measure trace amplitude Cj Step 1 Acquire and display a trace you want to measure Make sure all of the trace is within the graticule area but make the trace as tall as possible for best vertical resolution use the vertical icon if necessary 0O Step 2 Select the trace you want to measure go Step 3 Touch Cursors Cursor Type and Horizontal Bars C Step 4 Use the knobs to move the cursor positions to the top and bottom of the trace Use the Cursor 1 or Cursor 2 selectors in the Knob menu to increase the resolution of the knobs This lets you position the cursors more precisely The Av readout at the display bottom indicates the trace amplitude Measuring Time Between Points On Different Traces The following procedure shows how to use cursors to measure time be tween points on different traces CC Step 1 Create a display of the two traces you want to measure Make sure that the point you want to measure on each trace is visible on the display For
34. if the reference trace is not the selected trace the Phase measurement must be taken using a dual graticule display with the selected trace on one graticule and the reference trace on the other No other traces may be displayed on either graticule If either trace is an eye diagram the Phase measurement will use the first crossing on the trace regardiess of slope The Left Limit measurement parameter may be adjusted to control which crossings are used Prop Delay lf the reference trace is not the selected trace the Prop Delay measurement must be taken using a dual graticule display with the selected trace on one graticule and the reference trace on the other No other traces can be dis played on either graticule SNR Signal to Noise Ratio Amplitude SNR NoiseR where NoiseR Noise measured in RMS Dispersion mode For all hardware measurements the CSA 803A determines the voltage levels that are used for the measurement These are the mesial distal proximal and reference voltage levels If Level mode is set to absolute then these levels are set to absolute voltages using the knobs if Level mode is set to Relative then the CSA 803A performs the following steps to determine the baseline and topline voltages 1 ff Tracking is off the CSA 803A uses the baseline and topline values that were last set using the knobs or those left from the most recent use of tracking 2 If Tracking is on the CSA 803A acquires
35. in the infinite persistence and color grading display modes but not in nor mal or variable persistence modes The histogram display appears in red along the right side of the graticule A red box on the graticule outlines the limits of the histogram data trace data that fall outside these limits are ignored The amount of noise you see in the displayed signal will depend on the sampling head you have installed The illustration in Figure 2 51 shows the calibrator signal as acquired using an SD 24 sampling head If you are using a lower noise sampling head such as the SD 22 you wiil see less noise on the display The major menu area shows readouts for the histogram parameters and results a Top Btm Lft and Rgt are the limits of the histogram data displayed as a red box Mean is the mean vertical value of the trace data within the histogram limits RMSA is the root mean square deviation or standard deviation of trace data points from the Mean value m PkPk is the peak to peak measurement of the trace within the histogram limits w Hits is the number of trace data points that fall within the histogram limits Wfms is the number of traces waveforms acquired for the histogram utig is the percentage of points that are within one standard deviation 0 of the mean u pt20 and ws3e are the percentages of points that fall within two standard deviations and three standard deviations re spectively of the mean
36. ly In Binary mode the title block is terminated by a NULL character Pixel Data Compression significantly reduces the size of the pixel data block Without compression each data byte contains a single three bit pixel With compression two pixels are stored in the six low order bits of the data byte and the two high order bits are a repetition encoding with the following meaning Table 3 4 Repetition Encodings Bit7 Bit6 Meaning 0 1 Pattern repeats once 1 0 Pattern repeats twice 1 1 Pattern repeats three times 0 0 Following byte s contain repetition count Reference Hardcopy If the second byte of the pixel block has a value in the range 4 225 it is the pattern repetition count If the value is 1 3 decimal it is the high order bits of a 10 bit repetition count and the third byte of the pixel block contains the eight lower order bits Output Port The Output Port selector allows you to choose GPIB RS232C or Centron ics the PRINTER connector The selection must match the rear panel connection CSA 803A User Manual 3 95 Hardcopy Making a Hardcopy Once you have installed a printer and configured the CSA 803A properly you can make a hardcopy of the screen by pressing the HARDCOPY button on the front panel The HARDCOPY Button ACQUISITION SEQUENCE autoser J HARDCOPY N SETTING AE Figure 3 46 Front Panel Hardcopy Button When you press the HARDCOPY button the display freezes for
37. meets MIL T 28800E Type II Class 5 section 4 5 5 3 1 Non operating sampling heads not installed meets MIL T 28800E Type Ill Class 5 section 4 5 5 4 1 Operating meets MIL T 28800E Type Ill Class 5 section 4 5 5 4 3 Packaged product sampling heads not installed meets NSTA Proj 1A Packaged product sampling heads not installed meets NSTA Proj 1A No disruption or degradation of performance up to 10 kV No damage to instrument up to 20 kV Appendices CSA 803A User Manual Appendix B Specifications The specifications in Tables B 8 through B 14 apply to the CSA 803 Com munications Signal Analyzer only See Tables B 1 through B 7 for specifica tions for the CSA 803A Communications Signal Analyzer Table B 8 CSA 803 Vertical System Specifications Characteristic Specification Input sources Mainframe Bandwidth Risetime Amplifier gain accuracy Vertical resolution Trace data Hardware measurements Input sensitivity Offset accuracy Offset range Offset resolution Measurement level accuracy Vertical acquisition resolution Single graticule Dual graticule Vertical display resolution single graticule Dual graticule 2 sampling heads 4 channels Dependent on sampling head Dependent on sampling head 1 of full scale range 8 bits 14 bits 2 mV div to 255 mV div in 1 mV div steps 2 mV 2 V 0 25 mV 2 mV 25 points div 25 points div 50 pixels div 25 pixel
38. of the trace on the display whenever you change horizontal size In the example above before you changed the horizontal size you could change the horizontal reference point to the center of the display Then the part of the trace that was in the center of the display remains in the center of the display after the the horizontal size changes The current setting for horizon tal reference point is indicated by a letter next to the horizontal icon L indicates the horizontal reference point is set to Left C indicates Center and R indicates Right The horizontal reference point applies only to horizontal size In Pan Zoom mode the Horz Pos Gr setting serves a similar purpose Use the Horizontal Desc pop up menu of the Waveform major menu to control the horizonta reference point see Figure 3 53 The pop up menu has three selectors in the section labeled Horizontal Reference Point Left Center and Right The selector for the current setting is highlighted Touch the selector that corresponds to the setting you want In some cases changing the horizontal size control time per division may force the horizontal position to change For example with the reference point set to Center small main position settings may cause the first point of the record to reach the minimum delay for the trigger point Further in creases in the main size will cause the horizontal position to be moved to maintain the minimum delay for the first sample of th
39. tive slope Continue the search to the right to find the first upper signal noise ratio level crossing to the right of the first mesial crossing The horizontal coordinate of this crossing is Cross 2 Search the measurement zone for the leftmost mesial crossing of nega tive slope Continue the search to the right to find the first lower signal noise ration level crossing to the right of the second mesial crossing The horizontal coordinate of this crossing is Cross 3 If Cross lt Cross set Cross Cross Cross Cross and Slope positive If Cross gt Cross set Cross Cross Cross Cross and Slope negative 4 Calculate the width Width Cross Cross Linear interpolation between vertical points and between time intervals is necessary to determine the crossing time when the mesial value does not correspond to acquired data The algorithms for statistical measurements are identical to those for soft ware measurements except as noted below A statistical measurement represents ail the data in the color graded database representing many acquisitions of the selected trace The IEEE histogram method is always used to determine topline and base line when tracking is on See page D 12 for a description of this method The proximal mesial distal and reference values are then determined as percentages of the topline and baseline In statistical measurement mode the CSA 803A creates a voltage
40. which choices are logical at any time a Programmable contro of the CSA 803A that allows it to be run from an attached computer or instrument controller via the RS 232 C or GPIB interfaces Continuous self calibration system that ensures accurate stable trace data and measurement results Getting Started Description of Sampling Safety CSA 803A User Manual Introduction A traditional analog oscilloscope displays a trace dynamically as a beam is swept across the display horizontally The CSA 803A Communications Signal Analyzer separates a trace into discrete digital samples The CSA 803A captures a sampile before any amplification or attenuation is used to manipulate the signal This technique provides very high bandwidth for repetitive signals and makes bandwidth a function solely of the sampling head Thus as higher bandwidth sampling heads are introduced you can increase the capability of the CSA 803A just by adding a new sampling head The CSA 803A Communications Signa Analyzer uses sequential sampling to sampile one data point of the trace each time a trigger event occurs up to 200K samples per second Each successive trigger event samples the next point to the right of occurring later than the previous points sampled Once the entire trace has been sampled and all data points are accumulated the display shows the entire trace result For very slow trigger rates a partial trace is shown even before all data p
41. year from the date of shipment If any such product proves defective during this warranty period Tektronix at its option either will repair the defective product without gharge for parts and labor or will provide a replacement in exchange for the defective product In order to obtain service under this warrarity Customer must notify Tektronix of the defect before the expiration of the warranty period and make suitable arrangements for the performance of service Customer shall be responsible for packaging and shipping the defective product io the service center designated by Tektronix with shipping charges prepaid Tektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the Tektronix service center is located Customer shall be responsible for paying all shipping charges duties taxes and any other charges for products returned to any other locations This warranty shall not apply f io any defect failure or damage caused by improper use or improper or inadequate maintenance and care Tektronix shail Rott be obligated to furnish service under this warranty a to repair damage resulting from attempts by personnel other than Tektronix representatives to install repair or service the product b to repair damage resulting from improper use or connection to incompatible equipment or c to service a product that has been modified or integrated with other products when the effect
42. 1 25 The Enhanced Accuracy menu controls the calibration system See page 1 27 The Utility2 major menu provides access to the diagnostic system See page 1 29 The Cursors major menu controls the cursors markers that you position on your trace to make measurements Use the Cursors icon to display the Cursors major menu See page 3 29 1 17 At a Glance Waveform Major Menu poe Vertical Geserigtien TmT TO EERENS S Ee r OE aah This pop up menu lets you modify the trace i _ expression of the selected trace See page 3 209 Meinframe Channels i WAVEFORM TRIGGER MEASURE DISPLAY MODES STORE RECALL UTILITY q nonmmmmunn ThE More selector displays the alternate Trace Status major menu This displays the status of ali traces on the display See page 3 208 Kindow Mz Sh 24 Type This pop up menu controls the positior i Te le ce of window traces See page 3 225 Sampling head controls See page 3 169 1 18 Getting Started At a Giance feguiring Timebease Hein Samale Interval Samy le Interval point controls See page 3 111 i i i nee aa i Hf Made meh Trace i i i i f t H f f f XY trace controls See page 3 229 NTAS IT acs ea RE oN Ab ULSN Ea a Averaging and Acquisition control enveloping See page 3 3 See page 3 13 WAVE
43. 3 159 Power On Sequence asssssssnsresnvonsararosaessau 3 161 Warm Up Period 0cscvAwii cteduwawes ee tens tethered eee 3 161 R c rd Length wissen ac isstoos sees ieee keganas ces sets 3 163 RS 232 C Parameters 0c cece eee cnneueeesusucrenusnas 3 165 RS 232 C Connection s ensessaronssasarssreensnns 3 165 Setting RS 232 C Parameters 0cce cece nenenucaes 3 166 Sampling Heads viacacescde teas itvesteeiesiwkwtsdeeeuss nase 3 169 installing Sampling Heads 0 00 cs scene necerercecae 3 170 viii Contents Table of Contents Sampling Head Front Panel 0 00 ce eee ence ene eee 3 170 Controlling TDR and Smoothing Functions Corer 3 172 Time Domain Reflectometry TDR and Time Domain Transmission TDT 05 3 172 SMON anc stu newer du estan ant wants beer Caton Ge BAe 3 174 Channel A Delay 3 10 peck Minaene tenant lew ete eiiawe as 3 174 St red Settings ssi 24 eoret iani tiniee ioi E hai n EA seedy 3 175 Storing Settings s s sasusasnssrernnranrerennnnrrnnan 3 176 Recalling Stored Settings 00 ccc eee ewes 3 177 Deleting Stored Settings ccceeeneeccccnenaenese 3 178 Sequencing Through Stored Settings 2005 3 179 Stored ECCS s0 i iia teach Eten etree ees E ei p E 3 181 Storing WAGES omien erwan saad cece tiene hata tena 3 182 Recalling Stored Traces 5 ccc cece ee eee e ee ene eneees 3 183 Deleting Stored Traces
44. 6 Taking Delay Measurements a Example 7 Taking Comparison Measurements Using a Reference Trace u Example 8 Comparing Traces to Stored Traces m Example 9 Creating a Histogram Display Example 10 Taking TDR Measurements Each example demonstrates features and capabilities of the instrument The Reference section later in this manual also provides detailed information about instrument capabilities CSA 803A User Manual 2 1 Overview Ne A TT TE AAAA SEMANA A TRAINS ANN m PPR EHH Mi HHH HAIG a e a aa a Ai 2 2 Operating Basics Major Menu Buttons MENUS WAVEFORM MEASURE DISPLAY MODES L TRIGGER _ L L STORE RECALL Gal m C CSA 803A User Manual Example 1 Displaying a Trace This example shows how quickly you can display a meaningful trace on the display You wili also become familiar with the basic front panel controls For this example you will need a CSA 803A with at least one sampling head installed one SMA connecting cable and a static protection wrist strap You will begin by initializing the CSA 803A to its default settings Each exam ple in this manual begins with this step Read the Operator Overview section for information on installing your CSA 803A To the right of the display is a column of six buttons grouped under the title MENUS Each button has an indicator light that shows which button was pressed last Associated with each button is a major menu at the bottom of the dis
45. 7 _ _ Ref Voltage Mj RhoPos of M RA x pol of M where volts voltage at any point in M1 M2 rf rhofactor 2 for this trace Mj M1 or M2 Appendices Appendix D Aigorithms For trace M1 STO1 where STO1 was created from M1 volts tho RA x Tf cas rhopos RhoP Mi RhoPos of STO1 Hose or ae gt ila Ref Voltage M ORO OM RA per a where RhoPes of STO RnoPos of STO1 at the time STO1 was created rf rhofactor 2 for this trace Mj Mi or M2 For trace C4 x Ty Cn x Tg rhopos C xX poll x RhoPos of T rf C X poln x RhoPos of Ta as ea rhopos rhozero where G a numeric constant for example 1 0 or 0 5 T a channel or stored trace polj 1 or 1 polarity if Tj is a channel or rhofactor of a stored trace which equals the rhofactor of the live trace when the stored trace was created rf rhofactor C1 x polit Cn x poln however if this is 0 then _ ABS C x poll ABS C x poln AA E o E A AE Trace functions Smooth Filter and Avg have no effect on the formulas used for rho For trace Co Cy x Ty Cn X Tp the rho values produced are the same as if Co was 0 CSA 803A User Manual D 9 Appendix D Algorithms Signum Signum n 1 0 for W n gt 0 Signum n 0 for W n 0 Signum n 1 for W n lt 0 where n index into record of data points W n input sampled data point Squ
46. 803A can do both of these as automated measurements so you can compare the method of using auto mated measurements to using cursors For this example you will need a CSA 803A with at least one dual channel sampling head installed two SMA cables of equal length and a static protec tion wrist strap C Step 1 Initialize the CSA 803A press the UTILITY button in the MENUS column touch Initialize in the major menu and touch Initialize in the verification pop up menu Cl Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A C Step 3 Connect the CALIBRATOR output to a sampling head input C Step 4 Connect the INTERNAL CLOCK output to any available sam pling head input l md l l awd l C Figure 2 41 Connections for Example 6 C Step 5 Press the TRIGGER button Touch Source in the major menu area and select Internal Clock then touch Exit _ Step 6 Press the UTILITY button and touch Instrument Options Select Vectored Trace in the Instrument Options pop up menu CSA 803A User Manual 2 67 Example 6 Taking Delay Measurements Using Cursors C Step 7 Press the SELECT CHANNEL button on the sampling head input channel you have connected to the calibrator signal C Step 8 Turn the top knob to the left to set the horizontal scale to 10 ns div You should see the calibrator signal on the display The Cursors Major Menu
47. CALIBRATOR output connected to You will need to set the trigger source to Internal in order to display the calibrator signal C Step 6 Press the TRIGGER button to display the Trigger major menu L Step 7 Touch the Source selector in the major menu area and select Internal Clock in the Source pop up menu Select Exit to remove the pop up menu 2 19 Example 2 Managing Multiple Traces C Step 8 Press the AUTOSET button above the sampling heads You should see several cycles of the calibrator signal on the display as shown in Figure 2 13 73 Sm ee mpopatinsipia pekne EPren a apne hyata heit him com i f i i i i Hi ey i i bs x H i K E 1 Heal a Va Wome gee slaris T E E j i i i i i i i i i i i i i i i 4 i 7 i i i i i j H i i j i H AN H i H i i P i i i i i i 2 EE i I d i it 3 i i i k i H i f fe j i i fs H j f H i i i f i p i i i I j E I E i j F i i Pe i i i i i i i 3 f D i i i H H L H i i i jo 3 aj i i i i i i i i i i i i i H bs Es ka H f i E i H i i j i i H i ipercrre sd pocrorteat pertoer ipderomeensk Lined 841 3ns Sas diu SA Hrs Figure 2 13 The Acquired Calibrator Signal 2 20 Operating Basics Vectored Traces CSA 803A User Manual Example 2 Managing Multiple Traces The trace appears as individual dots on the display so you cannot see the rising and falling
48. Calibrate biowby compensation only if you notice that the displayed trace is not flat near the point of a large voltage change NOTE _ Some sampling heads do not require blowby compensation The blowby selector is not selectable dim for this type of head a Gain loop gain adjusts the dot transient response of a sampling head channel A channel that is out of adjustment will change the shape of the displayed trace as you change the horizontal size particularly at very high sweep speeds Trace noise can be increased when gain is greater than unity 1 This calibration is temperature sensitive If any of these conditions occur check the gain calibration Note that some sampling heads are not equipped to perform this calibration a Offset adjusts the DC voltage accuracy by setting the reference level to zero This calibration is temperature sensitive and can also be affected by gain calibration If the temperature of your environment changes if the sampling rate changes significantly or if you calibrate gain also calibrate offset i a TDR Amplitude adjusts the DC voltage levels of the TDR pulse TDR Amplitude is thermally stable and should rarely need to be calibrated If you notice the amplitude of the TDR pulse is not to specification you should calibrate the TDR amplitude The Reference Amplitude in the Graticules pop up menu is used in rho mode and should be set to match the voltage calibrated here nominally 250 mV Note that
49. Carriage Return CR LF or LF CR Touch the selector repeatedly until the appropriate setting is displayed in the selector Verbose lets you set verbose ON or OFF When verbose is on the CSA 803A posts to the computer a message indicating the success or failure of each command sent to the CSA 803A When verbose is off the computer can specifically query the CSA 803A about the success or failure of each command if so programmed s RS232C Debug lets you set debug ON or OFF When debug is on the CSA 803A displays each command from the computer as it is exe cuted The messages appear at the top of the display Debug off is the normal mode of operation Set debug on if you need to watch the result of each CSA 803A command of a program that is running in the com puter When debug mode is on it slows performance significantly CSA 803A User Manual 3 167 RS 232 C Parameters 3 168 Reference CSA 803A User Manual Sampling Heads A sampling head is a small plug in device that samples electrical signais and converts them to a much lower speed analog output signal At least one sampling head must be installed in the CSA 803A to acquire signals Several types of sampling heads are available The type and number of sampling heads you wili use depends on the tasks you are performing with the CSA 803A The CSA 803A mainframe provides four compartments for sampling heads as shown in Figure 3 78 Only the two right compartments
50. Color Maps To Max 2 1 to Max Pale Yellow Trace Color 1 Max 4 1 to Max 2 Rose Trace Color 2 Max 8 1 to Max 4 Purple Trace Color 4 Max 16 1 to Max 8 Light Blue Window Trace 1 to Max 16 Green Trace Color 3 D 27 Appendix D Algorithms D 28 For Max 6 and Max lt 15 sf Scale Factor Hit Density Max Default Color Maps To Max sf 1 to Max Pale Yellow Trace Color 1 Max sf 1 to Max sf Rose Trace Color 2 Max s 1 to Max sf Purple Trace Color 4 Max sf 1 to Max sf Light Blue Window Trace 1 to Max sf4 Green Trace Color 3 For Max lt 6 Hit Density Default Color Maps To Max Pale Yeliow Trace Color 1 Max 1 Rose Trace Color 2 Max 2 Purple Trace Color 4 Max 3 Light Blue Window Trace Max 4 Green Trace Color 3 For all points where Hit Density lt 0 no color is assigned Note that if Max is less than 5 not all colors will be represented on the display Appendices Selected Message Descriptions CSA 803A User Manual Appendix E Messages The CSA 803A displays a message at the top of the display whenever one of the following events occurs m Errors The CSA 803A cannot perform a requested operation m Warnings The instrument performs the requested operation but warns you that the results may be corrupted or meaningless m Ready Messages The CSA 803A is waiting for your response to complete the task Operation Complete Messages An oper
51. Color N selectors at the right side of the Color pop up menu The selectors at the right side of the pop up menu show the number of the color HLS hue lightness and saturation assigned to that trace for exam ple Trace Color 3 The box next to the selector displays the color of the trace To change the color of trace 3 touch Trace Color 3 Notice that Lightness and Saturation are highlighted and the knobs are assigned to Lightness and Saturation Turn the knobs to change the color attributes If you touch Color the menu will be removed and you can see the color graded display better The knobs are assigned to Lightness and Saturation as long as you are in the Utility major menu You can now change the color and see how the new color works with the other colors in the color graded display Changing the Selected Tra Color has no effect on the Color Grad ing colors To return to the Display Modes major menu press the DISPLAY MODES button 3 46 Reference CSA 803A User Manual Display Persistence Limiting Acquisition in color grading mode every pixel on the screen is assigned a bin which counts the number of samples that fall on that pixel Each bin can hold a maximum count of 65 535 f a sample falis into a bin which is full an over flow is generated You can limit the number of acquisitions performed based on the number of times overflows occur The Set N MaxContrast selector controls the number of overflows allowed before
52. Complex Traces B45mv divi Aberration Snevdiv 168 6ns Figure 2 23 Complex Trace Aberration Caused by Off Graticule Component In the last few steps you have moved the complex trace by selecting and moving one of the component traces Since you have the component traces on the display this is easy to do Usually when you display a complex trace you will not be displaying all the traces that represent the individual channel signals You can select this complex trace and move it with the knobs However when you do this you are actually moving only one component input chan nel of the complex trace Whenever the knobs are set to vertical size and offset the Knob menu selector at the lower right corner of the display becomes a Chan Sel selec tor see Figure 2 24 Touch this selector to choose which channel you wish to move Repeatedly touching the selector lets you choose from ail of the input channels that make up the complex trace Chan Sel Selector Figure 2 24 The Chan Sel Selector in the Knob Menu 2 36 Operating Basics CSA 803A User Manual Example 3 Defining Complex Traces 0O Step 17 Touch the difference trace to make it the selected trace Cl Step 18 Observe the Chan Sel selector in the Knob menu and then turn the top knob to the right to set the vertical size to 100 mV div You may need to turn the bottom knob to position the trace completely on the gratucuie L Step 19 Touch Chan Se
53. D 15 Appendix D Algorithms Frequency Domain Measurements There are two modes of operation harmonic and peak search If Search Mode is set to harmonic the instrument will determine the fundamental frequency fo by searching for the highest peak of the FFT magnitude in the measurement zone The harmonic components are computed asn x fo where n is the user defined harmonic number In peak search mode no harmonic relations are assumed between the spectral components A spectral peak is defined as a peak of the FFT mag nitude waveform greater than a user adjustable reference level The user can specify the index of the spectral peak to be measured In order to improve the frequency measurement resolution beyond the sampling resolution the frequency of a peak in either harmonic or peak search mode is determined by using an FFT interpolation algorithm Table D 2 Values of icoeff for FFT Windowing Functions FFT Window icoeff 0 Icoeff 1 icoeff 2 Blackman 2 5486667398 1 5170635356 1 0632064084 Blackman Harris 3 2326135798 2 1999343343 1 0653584909 Hamming 1 8732586725 0 7978694346 1 1507784758 Hanning 2 0 1 0 1 0 Rectangular 4 0 0 1 0 Triangular 1 7708896670 0 7177145486 1 1063502367 NOTE All even points of the frequency magnitude waveform are results of FFT calculation and all odd points are linearly interpolated results Thus the algorithm ignores all odd points The real frequency resolution is twice the fre
54. Displayed traces are numbered 1 through 8 A new trace is always given the lowest available number Tracking The process of automatically adjusting the measurement parameters or window position to reflect changes in the trace Trigger An electrical event that initiates acquisition of a trace as specified by the time base Uptime The number of hours the instrument has been powered on Vertical Description see Trace Expression Waveform The visibie representation of an input signal or combination of signals Identical to trace CSA 803A User Manual G 5 Glossary G 6 Window A trace that represents a horizontally expanded portion of another trace XY Trace A trace where both horizontal and vertical position of the data points reflect signal data YT Trace A trace where the vertical position of the trace data points reflects signal daia and the horizontal position of the trace data points reflects time Glossary A Accessories A 1 A 2 Acquire Desc pop up menu 3 3 3 14 3 16 Acquisition 3 1 3 6 conditional 3 3 stopping and starting 3 3 ACQUISITION button 3 3 Algorithms measurement D 1 D 12 D 28 trace function D 1 D 17 Aliasing 3 77 All trace status menu 3 208 3 209 ANSI Standard Masks 3 127 3 136 APC 3 5 See Connectors Audio feedback 3 7 Autoset 3 9 3 12 Options 2 70 using 2 9 AUTOSET button 3 9 Averaging 2 45 3 13 3 76 Axis labels 3 83 Axis units 2 76 2 92 2 93
55. FFT Magnitude waveform to find the nth spectral peak A spectral peak is defined as a waveform peak above a user adjusted reference level 2 Apply the FFT interpolation algorithm described above to find the spec tral frequency Spectral Magnitude The 11403A computes the magnitude of a har monic frequency by interpolating the FFT magnitude waveform and com pensating for the FFT windowing function effect 1 Given the frequency of the spectral component the routine identifies the two consecutive bins between when the harmonic component lies By using the interpolation factor determined for the fundamental frequency and the FFT window equations the amplitude of the harmonic peak is determined 2 For the amplitude of the fundamental given the two highest spectral components S jand 7 See Spectral Frequency the ampli tude of the fundamental is if S O gt S Dmax S if S 1 gt S max S IJanddA lt 1 4 max Al Sine AAA x A Ge XA x weorrect where weoeff 1 n 5 ee x A weorrect 7 wcoeff 0 Avi where 7 is the FFT window order For the triangular window the computation is different AL Se m AX aaam X WCOITOEE Sin a x HF x 3 where correct is the window correction weoeff are FFT window coefficients m is the window order D 21 Appendix D Algorithms Table D 3 Values of wcoeff and m for FFT Windowing Functions FFT Window weooeff 0 w
56. Figure 3 23 Figure 3 24 Figure 3 25 Figure 3 26 Figure 3 27 Figure 3 28 Figure 3 29 Range Figure 3 30 Figure 3 31 Figure 3 32 Figure 3 33 Window Figure 3 34 Figure 3 35 Figure 3 36 Window Figure 3 37 Figure 3 38 Figure 3 39 Figure 3 40 Figure 3 41 Figure 3 42 Figure 3 43 Figure 3 44 Figure 3 45 Figure 3 46 Figure 3 47 Figure 3 48 Figure 3 49 Figure 3 50 Display Figure 3 51 Figure 3 52 Figure 3 53 Figure 3 54 Figure 3 55 Figure 3 56 Figure 3 57 Figure 3 58 Figure 3 59 Figure 3 60 Figure 3 61 List of Figures The Color Grad Scale Pop up Menu The Enhanced Accuracy Major Menu The Calibrate Ali Pop up Menu 0 00005 A Typical Calibration Pop up Menu 4 Loop Gain Calibration in Vectored Trace Mode An Eye Diagram Display iwc Xe nannies dod taacatenaceen The Deffra Pop Up Menu s cwdae cic a ein scwcd Location of the FFTmag Icon onthe Display Equations for Frequency Interval and Frequency i 2 The Instrument Options Pop Up Menu Paired Dots Cursors on an FFT Magnitude Display Using Split Dots Cursors to Measure FFT Phase FFT Magnitude Displayed Using Rectangular ee ee es FFT Magnitude Dispiayed Using Triangular Window FFT Magnitude Displayed Using Blackman Window FFT Magnitude Displayed Using Blackman Harris Se FFT Magnitude Displayed Using Han
57. HiRes mode will be very siow Only Draft screen mode will produce usable output with the HP LaserJet Either the PRINTER Cen tronics connector RS 232 C connector or the GPIB connector may be used HPGL supports the HPGL color plotter command set When HiRes is selected under Screen Format an HPGL hardcopy will show graticules axis labels all waveforms and the major menus at the bottom of the screen You can suppress the plotting of the major menus by selecting Draft under Screen Format Color graded displays are not plotted with HPGL Supported plotters include the Tek HC100 HP 7475 and HP 7550 These printers can be connected to the PRINTER Centronics connector The HP 7474 and HP 7550 may be connected to the GPIB or RS 232 C connector 3 92 Reference CSA 803A User Manual Hardcopy Color Map The selections in the Color Map section of the menu become available whenever a color printer or plotter is selected A color selector is available for selected elements of the display To change a color simply select the element in the menu then use the contro knobs or keypad pop up menu to adjust the setting To restore the color map to its factory default settings touch the Default Color Map selector The color selections are expressed in terms appropriate to the selected printer When Tek 4692 is selected the colors are expressed as hexadeci mal RGB values For the Tek 4696 selection thirteen color name selections are av
58. If the trace record point is out of the range of the graticule the label will remain at the top or bottom of the graticule You can select a trace by touching its displayed label Reference Mask Testing The CSA 803A enables you to perform mask testing see Figure 3 57 using the Standard Masks and Mask Testing pop up menus The Standard Masks pop up menu lets you select a mask from a collection of 38 prede fined telecommunication masks These permanent masks include 18 CCITT standard masks 8 ANSI SONET standard masks 10 ANSI 71 102 standard masks and 2 miscellaneous standard masks The Standard Masks pop up menu is accessed from the Display Modes major menu Figure 3 57 Mask Testing on an Eye Diagram CSA 803A User Manual 3 119 Mask Testing Masks are selected and created using the Mask Testing pop up menu The Mask Testing menu lets you perform mask testing using the standard masks or create a custom mask for testing The Mask Testing pop up menu is accessed from the Display Modes major menu You can create up to 10 custom masks of up to 50 points each The Mask Testing menu also lets you specify that acquisition stop after a set number of trace acquisitions or after a set number of mask hits have been acquired To remove the Mask Testing menu touch Exit 3 120 Reference Using Predefined Telecommunication Masks CSA 803A User Manual Mask Testing The predefined telecommunication masks are available as Opt
59. Normal Maximum trigger input Direct Prescaler Trigger leve Trigger level resolution Trigger accuracy Trigger sensitivity Direct DC coupled Prescaler AC coupled Main and window position Initial window delay Strobe skew adjustment External Direct Internal Clock or External Prescaler Free runs after 20 ms timeout Acquisition only after trigger event 41 5 Vto 1 5V 2 5 V to 2 5 V 1Vto 1V 1 mV 10 of full scale 40 mV peak peak from DC to 200 MHz increasing to 150 mV at 800 MHz increasing to 250 mV at 2 5 GHz 600 mV typical peak peak from 2 GHz to 8 GHz Less than 2 V from 8 GHz to 10 GHz Minimum 40 ns pre trigger required 40 ns to 50 ms in 1 ps steps 1 5 ns B 9 Appendix B Specifications Table B 12 CSA 803 Display Specifications Characteristic Specification CRT 81 2 inch diagonal color magnetic deflection Vertical raster orientation Nominal screen size 6 087 inches vertical by 4 496 inches horizontal Character display Character height 0 10 in upper case Character cell 16 pixel vertical by 10 pixel horizontal Table B 13 CSA 803 AC Line Power Specifications Characteristic Specification Voltage ranges 90 to 132 Vas or 180 to 250 Vans Voltage ranges apply to trace distortion which reduces peak line voltage 5 Frequency 48 Hz to 440 Hz Power 320 W Current 4 6 Arms at 50 Hz 90 V line with 5 clipping Fuse 6 A 250 V normal blow Appendic
60. Parameters in your sampling head manual To adjust Channel A Delay press the WAVEFORM menu button on your mainframe instrument and select Sampling Head Fne s from the Waveform major menu Touch the Channel A Delay selector to set the knobs to con trol that parameter NOTE Be aware that not all sampling heads provide the Channel A Delay selector Reference Stored Settings When you initialize the CSA 803A you recall a stored front panel setting that was established at the factory You can save your own front panel settings for quick recall If you establish a test setup you might want to store the setting and go to another task After the setting has been changed because of the intervening work you could recall the test setting that you saved Masks are saved with stored settings so you can use stored settings to store sets of masks for different tests The instrument has a set amount of memory available for saving stored settings and stored traces The number of front panel settings you can save depends on how much memory is being used to store traces Assuming that no traces are stored you can store approximately 50 front panei set tings You can recall a stored front panel setting anytime You can also use the SEQUENCE SETTINGS button to recall stored settings in a specific order This is useful if your work requires several instrument setups for standardized tests Stored settings are saved when you power off the inst
61. RRR ARAN HRA RMR ee ROR Enhanced Accuracy Major Menu 000 eee cece eee Utility2 Major Menu Ce ee RERSDINREKESARKUANNBAAEANAOARKADNUN xili X X 1 1 1 1 1 3 1 3 13 1 3 1 3 1 4 1 4 1 4 1 4 1 4 1 4 1 5 1 5 1 5 1 6 17 1 9 1 11 1 11 1 12 1 13 1 14 1 15 1 16 1 18 1 20 1 21 1 22 1 23 1 25 1 27 1 29 iii Table of Contents Operating Basics OVOIVIOW aise Se seSare tarina nia ta Waa adds wind a Re wiih aN 2 1 Example 1 Displaying a Trace 0c cece ener ee rene cannes 2 3 Major Menu Buttons 00 cece cee eee eee eee ee eneeees 2 3 The iGuch Panel 4idcciieed caves san een a os de cies 2 5 Menu Selectors 62 Scene nis eee eee obs tu eee a ed 2 5 Connecting Cables ssasssuursarsensnenensrnuarouanu 2 6 Pop Up Men s necare snars erante eee o a 2 8 BUIGOSEE 6 coi cele tee E A EE E EE a 2 9 Autoset Options lt iise venice Kees ded cae eaaw es ees Maas 2 10 THE KNOBS 2a cttyovenrk sauder cessed ee eo name rae a 2 12 ICONS sstaeteteal ei aaae ei ete tart Swarecventes ce east and 2 13 Keypad Pop Up Menu and Knob Resolution 2 15 Major Menu Knob Assignments 02ceceeeeeseeeee 2 17 Example 2 Managing Multiple Traces 20c0eeeeeeeee 2 19 Vectored Traces 225 5 6 scons derek satatigsivausviwene dee 2 21 Adding Another Trace 000 cc ese n ence een eects eeenen 2 22 Selecting Traces by Touch 0 02 e sc ee ene ne ences 2 2
62. Typical Individual Measurement Pop up Menu in Figure 3 69 the Left Limit measurement parameter is set to 36 The left limit vertical line is positioned 36 of the way across the graticule and the CSA 803A measures the frequency from the first complete cycle to the right of the left limit The highlighted portion of the trace shows the area being measured The following table shows the measurement parameters Some apply only to hardware measurements some only to software measurements some only to statistical measurements and some apply to all three No pop up menu for an individual measurement uses all these parameters only the ones that apply to that particular measurement are shown in the pop up menu Changing a measurement parameter in one measurement changes it in all measurements of the selected trace that use that parameter 3 150 Reference Measurements Table 3 12 Measurement Parameters SW HW Stat Name Definition y y a Baseline The 0 level on which proximal mesial reference level and distal levels are based When tracking mode is Both or Baseline the CSA 803A repeatedly de termines the baseline and you cannot adjust it When tracking mode is Off or Topline you can set baseline or you can have the CSA 803A set it once by touching the Setup selector 1 Za Data Interval Determines whether the measurement will be taken from one cycle of the trace or the entire measurement zone al Dispersion Sel
63. a 2 048 point trace record and builds a histogram The CSA 803A determines the baseline and topline voltages from the histogram The histogram algorithm is identical to that used for software measurements D 25 Appendix D Algorithms 3 Using the baseline and topline voltages CSA 803A calculates the mesial proximal distal and reference levels from the percentage levels set using the knobs 4 The CSA 803A acquires a new trace record of the current record length The measurement hardware determines the dot number s on the trace s where the signal crosses the level s required for the measure ment The dot number is affected by the user settings for the transition number and filtering and if appropriate slope The determination of which dot represents a level crossing is not performed on the digitized trace data but on the analog signal using comparators in the measurement circuitry Cross Cross Dly T x M where Dly delay time from trigger to left edge of selected trace T time between successive dots of selected trace M selected trace dot number from comparators Fall Fall T x M M where M distal dot number from comparators M proximal dot number from comparators T time between successive dots of trace Frequency 1 N R E A M where M first mesial dot number from comparators M second mesial dot number from comparators T time between successive dots of trace Period Pe
64. a short time The shades of intensity on the display may be altered The printer starts printing immediately The length of time that the display is frozen depends on the hardcopy mode complexity of the display and memory available for hardcopies During this pause the CSA 803A formats and buffers the print commands After the pause the CSA 803A returns to normal operation and continues to print the hardcopy When the display becomes active again you may oper ate the CSA 803A without affecting the hardcopy being printed You can also initiate a new hardcopy at this point The CSA 803A will auto matically queue multiple screen displays for hardcopy output The number of hardcopies that can be queued is subject to the amount of available memory _ When the hardcopy is printed a message is displayed The hardcopy is not compiete until this message appears You should not turn off the CSA 803A perform seif test diagnostics or use the Extended Diagnostics menu until the hardcopy is complete or the hardcopy will be terminated before it is finished NOTE Do not turn off the CSA 803A or perform diagnostics until the hard copy is complete 3 96 Reference Terminating A Hardcopy In Progress Hardcopy Defaults CSA 803A User Manual Hardcopy You can terminate a hardcopy by selecting Hardcopy Abort in the Hard copy pop up menu A message will appear stating that the hardcopy has been cancelled You can also terminate t
65. all ones Pair Coaxial Pair 2 048 Mb s Same as data 75 Q AIS ail ones Pulse 8 448 Mb s Same as data 75 Q AIS all ones Pulse 34 368 Mb s Same as data 750 AIS all ones Zero Pulse 139 26 Mb s Same as data 750 CMI all zeroes One Pulse 139 26 Mb s Same as data 750 CMI all ones STM1 155 52 Mb s Ciock or data 75 CMI PRBS or live Data CEPT 565 Mb s Clock or data 500 PRBS or live data Single Pulse 64 kb s Same as data 1109 AIS all ones Double Pulse 64 kb s Same as data 110 Q AIS all ones Data Pulse 64 kb s Same as data 110 Q AIS all ones Timing Pulse 64 kb s Same as data 1109 AIS all ones Pulse 1 544 Mb s Same as data 100 B8ZS 100000001 00000001 000 0000 Symmetrical 6 312 Mb s Same as data 1100 B6ZS Pair 100000100000100000 Coaxial Pair 6 312 Mb s Same as data 750 B8ZS 100000001 00000001000 0000 Pulse 32 064 Mb s Same as data 75 B3ZS 100100100 Pulse 44 736 Mb s Same as data 75 QO B3ZS 100100100 Pulse 97 728 Mb s Same as data 75 Q AIS All ones 3 133 Mask Testing ANSI SONET CCITT SDH Optical Standards Masks Signal Requirements O E converter should comply with ANSI CCITT specifications Data Type NRZ PRBS SDH SONET Frame or live data Trigger Signal Clock recovered clock or data signal Table 3 7 ANSI SONET CCITT SDH Optical Standards Masks Mask Name Data Rate Oct 51 84 Mb s OC3 STM1 155 52 Mb s ocg 466 56 Mb s OC12 STM4 622 08 Mb s OC18 933 12 Mb s OC24 1 2442 Gb s OC
66. area You will store this trace and then define a new trace that shows the differ ence between a signal and the stored trace Storing a trace means storing a copy of each data point that forms the trace on the display A limited amount of memory is available for storing traces and for storing front panel settings As you store traces and front panel settings the instrument keeps a running total of the available memory In the pop menu below available memory is shown under Free NonVolatiie RAM Figure 2 49 The Store Recall Major Menu and Store Trace Pop Up Menu The STORE RECALL button lets you store and recall traces and front panei settings In addition you can clear traces discard accumulated data and force re acquisition and delete traces See Figure 2 49 C Step 8 Press the STORE RECALL button then touch Store Trace and select Trace 1 in the Store Trace pop up menu The CSA 803A has stored a trace in memory named STO 1 Once the trace is stored there is no reason to leave its source on the display C Step 9 Touch Remove Cir Trace 1 and then touch Remove Trace 1 in the pop up menu CJ Step 10 This step is optional If you wish to see the stored trace with which the comparison will be made touch the Recall Trace selector and select TO1 in the pop up menu 2 82 Operating Basics Example 7 Taking Comparison Measurements Using a Reference Trace Once the CSA 803A has been set up with a comparison
67. between the cursors in volts This is the amplitude of the calibrator signal CSA 803A User Manual 2 69 Example 6 Taking Delay Measurements Using Cursors Figure 2 43 Horizontal Bar Cursors Placed Over a Trace The same value can be determined using the automated measurement system The sequence to do this is press the MEASURE button touch Measurements in the major menu area and then the Peak Peak selector in the pop up menu The measurement value is visible in the Peak Peak selector in the major menu area Exit will allow you to observe the trace as the measurement readout is updated NOTE The Peak Peak automated measurement value will include any signal noise 2 70 Operating Basics Using Split Dot Cursors CSA 803A User Manual Example 6 Taking Delay Measurements Using Cursors Dot cursors are small dots that float on the trace You position them hori zontaily using the knobs but their vertical height is determined by the trace on which they are are placed Split dot cursors operate the same way but they are placed on two different traces of your choice In this example you will have one trace on each of two graticules but this is not required to use split dot cursors You will follow the convention of displaying the traces before invoking the cursors C Step 12 Establish a dual graticule display press the WAVEFORM button and touch the Graticules and Create Second Graticule selec tors C Ste
68. bus See page 3 79 1 12 Getting Started At a Glance Display and Touch Panel The display shows the output of the instrument such as traces and meas urement information The display is combined with the touch panel to pro vide a touch menu system Touch the selectors that are displayed in the various menus to execute those items Each menu selector has a shaded top portion that names the selector and a lower portion that shows the current status of the parameter that the selector controls Z66m cro paa A TS oe g tn i fp nenene i Selected trace highlighted See ae 3 keg he hSe rate e and unselected trace Axis ON Selah ae ge eco labels and readouts apply to i i the selected trace Traces can ie d See page 3 208 i Ean a 4 3 4 im miee ks oe terial j rij wed BPI Faramseters A pop up menu provides a temporary dialog to let you set specific parameters This is the GPIB RS232C pop up menu which is accessed by touching the GPIB RS232C selector in the Utility major menu Several different major menus are available You The Knob Menu always shows the parameters dispiay and use the major menus by pressing the the knobs are currently assigned to control top major menu buttons This is the Utility major two selectors You can also use the knob menu menu Touch the GPIB RS232C selector to to remove traces from the display You can touch display that pop up menu See page 1 16 f
69. can be used for acquisition The two compartments on the left are power only They are for use with non acquisition heads such as the SD 51 Trigger Head or the SD 42 and SD 46 Optical to Electrical Converters Some sampling heads have two separate channels others have only one Acquisition Sampling Head Compartments Power Only Sampling Head Compartments Figure 3 78 Location of Sampling Head Compartments 3 169 Sampling Heads Installing Sampling Power off the instrument before installing or removing sampling heads To Heads install a sampling head place the head in the compartment and slowly push it in with firm pressure Once the head is seated turn the screw shaft on the sampling head to tighten the head into place Never install or remove a sampling head with the CSA 803A power on Sampling Head Front The front panel of a typical sampling head is shown in Figure 3 79 The Panel sampling head illustrated the SD 24 TDR Sampling Head has two channels Screw Shaft 1 28 SELECT gf CHANNEL Bution Channel Indicator Light Yellow Top Channel Signal Connector TDR ON Light Red Bottom Channel SD 24 TOR SAMPLING HEAD Figure 3 79 Sampling Head Control Panel SD 24 shown 3 170 Reference CSA 803A User Manual Sampling Heads Each channel has a signal connector for signal input and for TDR step output Each channel also has a SELECT CHANNEL button and an associ ated yellow channel indicator light
70. causal and uses an average that is centered on each point A shifted filter causal and forms the aver age for each point based only on preceding points The filter mode is set in the Instrument Options pop up menu intg The integral of the argument Ln The natural logarithm of the argument Log The base 10 logarithm of the argument Signum The sign of the argument Signum returns 1 if an argu ment is greater than zero and 1 if less than zero 3 206 Reference Trace Definition and Management Table 3 13 Trace Functions Cont Function Trace Functions Sart The square root of the argument Smooth A moving average of a trace This function has two argu ments separated by a comma The first argument is the trace to be smoothed the second argument is the number of samples in the moving average If the second argument is 9 then 4 samples before each point and 4 samples after each point are averaged with the point value If the second argument is an even number one is added to it to make it odd Smooth can be applied to stored traces or a single channel live trace NOTE Stored traces are described on page 3 181 Defining Traces Using the Sampling Head Channel Button A short cut method of defining traces is available When you want to define a trace that represents a single sampling head channel you can press the SELECT CHANNEL button on the sampling head There are two limita
71. copied into the stored trace location with the lowest available number unless you select otherwise free Mon oalatiie RAM H448H bytes rarer nnanenaninananatanste nets Figure 3 85 The Store Trace Pop up Menu Use the following steps to store a trace O Step 1 Create a stable trace on the display L Step 2 Press the Store Recall major menu button and touch the Store Trace selector in the major menu See Figure 3 85 C Step 3 Observe the Set Next Sto selector on the pop up menu The trace you store will be assigned this number If you want to set this number to one other than the next available touch the Set Next Sto selector and adjust the knobs to select a number You can choose any number between 1 if no trace is currently stored and 9999 You cannot store a trace where another trace is already stored G Step 4 All displayed traces are listed in the pop up menu Touch the selector that represents the trace you want to store The Store Trace pop up menu keeps track of the amount of non volatile RAM available to store both traces and settings This information is listed under Free NonVolatile RAM This number will decrease after you store traces or settings and increase after you delete traces or settings You can also use the Store All selector to store all the displayed traces as separate stored traces In this case the Next Storage notation tells you the first storage number that will be used
72. designed to show how the instrument acquires common mode and differential TDR traces and how they relate to each other Differential TDR is quickly set up by using the Diff TDR Preset selector on the Sampling Head Fne s pop up menu This preset automates the setup for differential TDR by a Turning on both channels of the SD 24 a Turning on both step generators a inverting the polarity on one step generator a Autosetting both traces Turning on Baseline Correction a Changing the vertical scaling from volts to rho TDT Measurements You can make forward and reverse Time Domain Transmission TDT meas urements using the SD 24 To perform a TDT measurement connect one sampling head channel to the input of the device under test and the other sampling head channel to the output of the device under test You can then alternately enable the step generators on both channels and sampie the transmitted signal on the other channel to perform forward and reverse TDT measurements CSA 803A User Manual 3 199 TDR More About TDR When making differential or common mode TDR measurements it is impor Measurements tant that the two steps arrive at the same time at the reference plane usually the connection point to the device under test To check and adjust this condition disconnect the transmission cables from device under test at the point where the cables connect to the device If the cables aren t matched perfectly matching either
73. display is not yet warmed up you may not be able to see the mes sage Diagnostics in Progress Comm Test in Progress If the power on diagnostics are completed successfully the self test diag nastics are executed immediately and you will see the message Self Test in Progress on the display if the power on diagnostics fail one or more of the following indications will notify you a The instrument emits a high low beep The instrument freezes and a message appears on the display For example Dsy Kernel Failure RAM Data Bit a The instrument freezes and some of the front panel lights are turned on 3 36 Reference Self Test Diagnostics CSA 803A User Manual Diagnostics The CSA 803A automatically executes the self test diagnostics after the power on diagnostics are completed successfully The self test diagnostics can also be initiated by touching the Self Test selector located in the Utility2 major menu press the UTILITY button until the Utility2 menu appears and then touching Self Test in the verification pop up menu See Figure 3 16 Figure 3 16 The Self Test Pop up Menu in the Utility2 Major Menu The self test diagnostics take about 15 seconds to execute During this time you will see the message Self Test in Progress on the display You will also see the front panel lights blink on and off and you will see several test patterns on the display if the self test diagnostics are completed succe
74. edges For this example you will want to change the trace display so that the individuai dots are connected C Step 9 Press the UTILITY button to display the Utility1 major menu a Step 10 Select Instrument Options in the major menu area The Vectored Trace selector in the Instrument Options pop up menu controls whether the individual points of a trace will be connected on the display Right now you see Off displayed in the status area of this selector Step 11 Touch the Vectored Trace selector The selector now shows On as status C Step 12 Select Exit to remove the pop up menu You should see a trace display as shown in Figure 2 14 apene jan rile japie ee dru nat an ed Sates T re E eee i nii hs E z i RE M H K HE z i H j ji s A H i ary i H i ig H i i i pi pi i i Ae an 7 i i i i p ae gers i i i if H i H i i j ie ETE i is f i i Dn sot H H Fa i Siwy H i i i i j Jaig 3 i E a j i i i i i i i i i i 3 a i i f j y H H i i i E f i i i 3 J H i i i TE TS be os eemo l of vd lene de f 2 3 ci i i i i i i i A i i 3 3 i i j k E H T l a i de Py ea A j i i j i k i l i a ne ee ae i ae gat ewe el oe ee ee ee aa i r i i i J 1 i Sausediw SH oas Figure 2 14 A Vectored Trace Display 2 21 Example 2 Managing Multiple Traces Adding Another Trace Adding another trace to an existing di
75. is the same as touching the 7 icon to the left of the graticule Mode selects between Normal mode and Auto mode Auto mode supplies unsynchronized trigger events in the absence of trigger events on the trigger signal 3 214 Reference Triggering m Slope selects between a rising slope trigger event and a falling slope trigger event a Enhanced Triggering controls the state of the metastable trigger reject in the Direct trigger path Enhanced Triggering On causes the timebase to detect trigger events that are metastable and to reject the acquired data The point is re acquired on the next trigger event En hanced Triggering Off allows metastable trigger events to be displayed Touching the Enhanced Triggering icon toggles the setting between On and Off a High Frequency controls the state of the trigger hysteresis in the Trigger Input trigger paths High Frequency On removes trigger hyster esis and improves sensitivity but should be used only when the trigger signal edge has a slew rate of 1 V ns or greater This corresponds to a 320 mVp p sinusoid at 1 GHz High Frequency Off retains trigger hyster esis and improves noise rejection at low frequency Generally it should always be used below 1 V ns slew rate or a 320 MV p sinusoid at 1 GHz It can be used at all frequencies if there is sufficient trigger signal amplitude to reliably trigger the oscilloscope Touching the High Fre quency icon toggles the s
76. last For example you have the Trigger major menu selected The current knob assignments are Vert Size M1 and Vert Offset M1 you may be using a different channel number NOTE Major menu buttons perform knob assignments C Step 19 Press the WAVEFORM major menu button in the MENUS column The knob assignment changes to Main Size and Main Pos because that was the last assignment made using the Waveform major menu Example 1 Displaying a Trace 2 18 Operating Basics CSA 803A User Manual Example 2 Managing Multiple Traces This example demonstrates multiple traces and graticules on the display It aiso shows how to select and manage multipie traces For this example you will need a CSA 803A with at least one sampling head installed two SMA cables and a static protection wrist strap C Step 1 Press the UTILITY major menu button in the MENUS column touch the Initialize selector in the major menu and touch Initialize in the pop up menu C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A CJ Step 3 Connect the CALIBRATOR output to any sampling head input C Step 4 Connect the INTERNAL CLOCK output to any available sam pling head input sd ond l Cj Figure 2 12 Connections for Example 2 Display the trace coming from the calibrator C Step 5 Press the SELECT CHANNEL button of the channel you have the
77. major menu area are no longer empty but show the measured values you have specified see Figure 2 36 These values are updated continually 2 56 Operating Basics CSA 803A User Manual Example 5 Taking Automated Measurements 3 hd i i f F eaa irbes i ate T ee Aandi isoa Manta Pattee wits Maal Et ie yanat Fee NINA PM eisai a A pebea e a E Piai PANATAS ieaie i t 4 Main i Figure 2 36 Measurements of a Trace 2 57 Example 5 Taking Automated Measurements Measurement For each measurement more information is available and more control is Parameters and provided Touching the measurement selector in the major menu area does the following Annotations m Displays annotation lines on the graticule These annotation lines graphi cally show the portions of the trace that the measurement readout value is based on m Highlights the portion of the trace that the measurement is based on Displays a pop up menu that documents the annotation lines shows accumulated measurement statistics and allows you to assign the knobs to various measurement parameters C Step 11 Touch the RMS selector in the major menu area Often you will want to observe the annotation lines without the pop up menu hiding a portion of the trace For this reason annotation lines remain on the display even after a measurement pop up menu has been removed C Step 12 Touch the
78. measurement no further adjustment is necessary to make a series of deviation measure ments To compare the longer cable to the reference you have established C Step 15 Remove the short cable from the calibrator and sampling head and replace it with the longer cable connected in the same way The ACross measurement readout shows the difference in length of the cables by showing how much longer it takes a signal to travel through the second cable In a testing environment this method of measuring can be used to test a collection of cables to a specific tolerance without altering the setup on the CSA 803A CSA 803A User Manual 2 79 Example 7 Taking Comparison Measurements Using a Reference Trace 2 80 Operating Basics How Traces are Acquired CSA 803A User Manual Acquisition Acquisition is the process of digitizing data points from a signal and assem bling them into a trace record that is shown on the oscilloscope display Once you create a trace acquisition of the signal is continuous and you see a live trace on the display When the CSA 803A acquires trace records it bases the sampling process on a trigger event an electrical event that occurs on the trigger signal The trigger signal is independent of the signal being acquired See Figure 3 1 When the trigger event is detected the CSA 803A waits a specified period of time before sampling and digitizing the first trace point This time period is the horizontal p
79. measurement zone for the left most mesial crossing of the specified slope The horizontal position is Cross 2 Onthe second trace search the measurement zone for the left most mesial crossing of the specified slope The horizontal position is Cross 3 Calculate the delay Delay Cross Cross Linear interpolation between vertical points and between time intervais is necessary to determine the crossing time when the mesial value does not correspond to acquired data Rise 1 Find the first point in the measurement zone that is less than the proxi mal vaiue searching from left to right 2 From this point find the first proximal crossing and note the time t 3 From the proximal crossing examine points to the right looking for the distal crossing t Update if subsequent proximal crossings are found 4 Calculate the rise time Rise ta ty Linear interpolation between vertical points and between time intervals is necessary to determine the crossing times when the proximal and distal values do not correspond to acquired data CSA 803A User Manual D 19 Appendix D Aigorithms RMS _ SWG 1 WO RMS 2 m 2 where m index ofieft most measurement zone sample n index of right most measurement zone sample W j sampled data point The summation extends over the interval of time corresponding to one period when Data Interval is set to one period or the entire measurement zone when D
80. of such modification or integration increases the time or difficulty of servicing the product THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THIS PRODUCT IN LIEU OF ANY OTHER WARRANTIES EXPRESSED OR IMPRIED TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FORA PARTICULAR PURPOSE TEKTRONIX RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES europan vian samt we ira sat CSA 863A User Manual About This Manual This is the user reference manual for the CSA 803A Communications Signal Analyzer This manual has three sections The Getting Started section provides an introduction to the CSA 803A the Operating Basics section provides several examples on using the instrument and the Reference section provides complete reference information The first section of this manual Getting Started presents quick get ac quainted information and a map of the menu system Each menu is accompanied by pointers into the Operating Basics and Reference sections Other manuals that complete the documentation set for the CSA 803A Com munications Signal Analyzer The CSA 803A and 11801B
81. of the display 3 93 Hardcopy Data Format When Bitmap Dump is selected the screen data is transferred as an ASCII title block followed by a pixel data block The format of the pixel data is determined by the Data Format setting Touch this selector to cycle through the six available formats a TIFF sends a TIFF image This format conforms to Rev 6 0 of the TIFF specification Screen and Dithered screen formats generate Palette Color Class P prints Hires Draft and Reduced formats create Bilevel Class B prints TIFF Compacted sends a compressed TIFF image using PackBits compression Note that some application software will not accept Rev 6 0 compressed TIFF Class P images Screen formats are the same as for TIFF Binary mode bytes of pixel data are sent as a stream of binary values without delimiters a Binary Compacted mode pixel data are compressed before being sent See the discussion of compression below u BinHex mode converts every four bits into a hexadecimal character Each line is terminated by a new line character BinHex Compacted mode pixel data are compressed and then con verted into BinHex characters Title Block consists of three character strings terminated by new line characters The first line contains the firmware version numbers time and date and the CSA 803A ID number The second and third lines give the number of pixels per display line and the number of display lines respective
82. on the display lf the trace defining the X axis information is a displayed trace this process will leave two traces on the display the XY trace and the X axis information trace Once the XY trace is established you can remove the trace displaying the X axis information To restore an XY trace to normal YT mode select the XY trace and touch the Normal YT selector in the Horizontal Desc pop up menu Constellation diagrams are a common application of XY traces See Constel lation Diagrams on page 3 25 for more details 3 231 XY Traces 3 232 Reference Appendix A Accessories Standard The CSA 803A instrument package includes the following standard accesso Accessories Oe m CSA 803A User Manual this manual m CSA 803A and 11801B Programmer Manual Tektronix part number 070 8784 01 CSA 803A Service Manual Tektronix part number 070 8780 00 Power Cord North American 120 V Tektronix part number 161 0066 00 w Two 8 inch SMA interconnecting cables Tektronix part number 174 1120 00 a One foot SMA interconnecting cable Tektronix part number 174 1364 00 a Antistatic wrist strap Tektronix part number 006 3415 04 To obtain replacements refer to a Tektronix products catalog or contact your local Tektronix field representative Optional Accessories The following optional accessories have been selected from our catalog specifically for the CSA 803A For detailed information an
83. or by press ing the WAVEFORM major menu button in the MENUS column Operating Basics Labeling Traces CSA 803A User Manual Example 2 Managing Multiple Traces You can label traces to help you keep track of them You can specify a label of up to 10 characters for each trace and you can have these labels dis played with the traces on the graticule You can use letters of the alphabet upper or lower case Greek symbols graphic symbols or numbers in your label The trace label moves with the trace as the signal changes You can change the position of the label relative to the trace Use the Labeling pop up menu in the Utility major menu to control labels see Figure 2 18 CJ Step 20 Press the UTILITY button to display the Utility major menu C Step 21 Touch the Labeling selector in the Utility1 major menu The Display selector in the Labeling pop up menu turns on or off the dis play of all trace labels Display is currently turned off C Step 22 Touch the Display selector to turn display of trace labels on Cl Step 23 If it is not already highlighted touch the Dispiayed Traces selector There is a selector for each displayed trace Each selector shows a trace number the trace expression and the time base for that trace C Step 24 Touch the selector for Trace 1 The lower portion of this pop up menu displays selectors that let you type the label The selectors along the very bottom let you select the set of char
84. parameters Setting the default parame ters before creating the traces saves time over the process of changing the measurement parameters of each trace individually You access the default parameters through the Measurements pop up menu in the Measure major menu When this pop up menu is first displayed it shows a list of measurements and the Measurement Functions selector is highlighted If you touch the Default Parameters selector the menu changes to show the default parameters Defaults for either software hardware or statistics mode are shown de pending on whether Software Default Hardware Default or Statistics Default is highlighted at the top of the menu see Figure 3 71 You can change to another set of defaults by touching the appropriate selector Changing the default does not affect the current measurement mode Once the appropriate set of defaults is displayed touch the selector that names the default you want to set A knob will be assigned to set the value of that default parameter Once you have the defaults set the way you want them you can change all the measurement parameters of the selected trace to the default settings by touching the Initialize All selector This selector changes all the measure ment parameters of the selected trace only other traces are not affected 3 157 Measurements Measurements Figure 3 71 Measurements Pop up Menu with Software Defaults 3 158 Reference Power
85. record can be limited by choosing an FFT windowing function that tapers near the trace record ends The CSA 803A provides a rectangular FFT window which does not taper the time domain data and five tapering FFT windows of different shapes Each time domain FFT windowing function corresponds to a filter in the frequency domain Each frequency domain filter has a high central lobe or passband The width of this lobe determines how well adjacent frequency components can be resolved The height of the side lobes surrounding the central lobe determines how much leakage can occur Leakage is the spreading of energy from one frequency component across the displayed frequency spectrum low amplitude frequency components can be entirely masked by leakage To select an FFT windowing function repeatedly touch the FFT Window selector in the Instrument Options pop up menu in the Utility major menu This selector cycles through the available windowing functions The selected FFT windowing function shown in the selector s status area applies to all FFT trace displays The shapes of the FFT windowing functions and their effects on a signal composed of two sine waves are shown in the following discussion The Rectangular Window The rectangular window does not taper the time domain data In the fre quency domain the filter shape is sin x x This is the best window to use when you want to examine the frequency spectrum of a non repetitive signal The
86. rectangular window should also be used when you want to measure frequency components near DC Set the FFT Window selecior in the Instrument Options pop up menu to Rectangle to select this windowing function See Figure 3 33 3 74 Reference Fast Fourier Transforms Time Window Figure 3 33 FFT Magnitude Displayed Using Rectangular Window The Triangular Window The triangular or Bartlett window is the convolution of two rectangles haif the width of the window so the frequency spectrum of the triangular window is the product of the rectangular window s spectrum with itself Set the FFT Window selector in the Instrument Options pop up menu to Triangle to select this windowing function See Figure 3 34 iN yy AN Ny N M N Me WN un WV WA Mov fi Time Window 37G GkHzrdiy Frequency Filter Figure 3 34 FFT Magnitude Displayed Using Triangular Window CSA 803A User Manual 3 75 Fast Fourier Transforms The Blackman Window The Blackman window reduces leakage better than the Hamming window because of the lower side lobes in the frequency domain but the resolution of nearby frequencies is diminished Set the FFT Window selector in the Instrument Options pop up menu to Blackman to select this windowing function See Figure 3 35 Adk Ag Fl Pad NA Kas Biv AOANARAAA TANT aa a ee A YOY IRANIANA AnA DAARKANAA AEA S i web ETL AR Ds SAE RU RASI AAA SE AAR SAS AG TINE EA poco
87. remains at 512 points The 4096 point record length has the same sample interval the time be tween successive trace samples as 5120 point records The 4096 point trace appears shorter on the display than 5120 point traces Many Fast 3 163 Record Length Fourier transform algorithms require record lengths that are a power of two The 4096 point record length is provided as a convenience and the visual truncation ts a natural result You control the record length by using the Horizontal Desc pop up menu in the Waveform major menu The Main Record Length and Window Record Length selectors assign the knobs to set the record lengths The Horizontal Desc pop up menu shows the sample intervals for the current settings See Figure 3 75 ee Horizantal Deseristion Acquiring Timebase Main i amoje Interval z j Record Length Interval Section i XY Display Made NeStored Trace Figure 3 75 The Horizontal Desc Pop up Menu 3 164 Reference RS 232 C Parameters The CSA 803A can be controlled by a remote computer through one of two interfaces These interfaces are industry standards IEEE Std 488 GPIB and RS 232 C This manual does not discuss the details of connecting a remote computer to the CSA 803A or the syntax and capabilities of remote commands That information is found in the CSA 803A and 11801B Programmer Manual RS 232 C Connection Connect the cable from your computer to the RS 232 C connector
88. rho 3 87 3 88 seconds meiers and feet 3 87 3 88 B Baseline 3 757 D 12 D 28 Baseline correction 3 17 3 7971 3 200 Beep See Audio feedback Blowby Compensate pop up menu 3 53 3 57 Brightness See Display intensity Buttons 1 77 1 30 ACQUISITION 3 3 AUTOSET 2 9 3 9 HARDCOPY 1 7 3 96 3 97 MENUS 2 3 sampling head SELECT CHAN NEL 3 770 3 171 SEQUENCE SETTING 3 179 3 180 C Calibration See Enhanced accuracy Calibrator 7 6 Calibrator output 3 19 Calipers See Cursors CCITT Standard Masks 3 121 3 136 Chan Sel 2 36 2 42 Clear Histograms 3 105 Clear Cursors selector 3 37 Clear Trace pop up menu 3 5 3 6 Clearing traces 3 5 3 6 Clock See Time and date Color 3 27 3 22 3 23 Color Grading mode 3 44 Color pop up menu 3 27 3 22 3 23 Common mode TDR measurements 3 189 3 196 3 199 Compare amp References pop up menu 3 147 3 148 Connectors 7 77 71 30 APC 3 5 1 5 C 3 DIRECT 3 213 GPIB 3 79 3 82 3 89 GPIB 7 7 INTERNAL CLOCK 3 79 POWER 3 159 power 1 7 PRESCALE 3 273 PRINTER 3 89 printer 7 7 RS 232 C 3 89 3 90 3 765 RS 232 C 1 7 SMA 1 5 C 3 Constellation Diagrams 3 25 3 28 Cursor Type pop up menu 3 29 3 37 Index Cursors 3 29 3 34 accuracy 2 73 types 2 68 using 2 68 Cursors icon 3 30 D DefTra icon 3 204 3 207 DefTra pop up menu 3 204 3 207 DefWfm pop up menu 3 66 Delay Adjust pop up menu 3 54 3 58 3 60 Del
89. select an appropriate FFT windowing function The CSA 803A provides six common FFT windowing functions which are accessible from the Instrument Options pop up menu Touch the FFT Window selector to sequence through the six functions CSA 803A User Manual 3 71 Fast Fourier Transforms Using Cursors to Make Measurements 3 72 You can use the cursors to make measurements of an FFT trace display Select the FFT trace and touch the Cursors icon to display the Cursors major menu See Cursors on page 3 29 for more information on using cursors When making measurements on an FFT trace recall that the odd numbered points in the trace record are derived by interpolation The even numbered record points are the frequency lines peaks in the FFT magnitude always occur on the even numbered points You can see the peaks more clearly by using Pan Zoom to horizontally magnify the FFT trace NOTE The automated frequency domain measurements are described in Measurements on page 3 137 When you first display cursors on an FFT trace paired dots cursors are automatically selected with one dot cursor placed at DC and the other at Fmax You can use the paired dots cursors to make relative measurements of the peaks of an FFT trace See Figure 3 31 sia cd de Ya aid Bi 3 a H ALS a oe EA tani ee EE ee a a Winans ree ay PE Man e a ia a i 7 t H NEA Rete Figure 3 31 Paired Dots Cursors on
90. some sampling heads are not equipped to perform this calibration 3 53 Enhanced Accuracy a Delay Adjust lets you deskew different sampling heads to any one sampling head The reference head you choose is measured and the delay of the other sampling heads is adjusted to match that reference head Calibrate delay adjust only when you need to measure delays between two sampling heads to close tolerance When the Delay Com pensate selector is set to Off compensation of the sampling head delays is not done automatically and the deskew calibration is not maintained automatically by the system This calibration parameter is unique in that the delay adjust does not apply to individual channels but to the sampling head as a whole The delay adjust value is not stored in the sampling head but in the instrument mainframe and there is no factory default value Typical Calibration Method The five available sampling head calibrations are made in a similar way The following description is of the options used when making a typical calibra tion Further discussion of the manual method of making each individual calibration follows the description of the typical method To make a sampling head calibration touch the selector in the Enhanced Accuracy major menu that names the parameter you want to calibrate These include Blowby Compensate Gain Offset Delay Adjust and TDR Amplitude Each of these displays a pop up menu All of these pop up men
91. te ERAN AA AMAMAMANIA E E E e 5 Eaa e ra Sete Ve Me E i j Figure 3 35 FFT Magnitude Displayed Using Blackman Window The Blackman Harris Window The Blackman Harris window has the widest pass band lowest frequency resolution and lowest side lobes best elimination of leakage of the six window functions This window is especially good for viewing a broad spectrum Set the FFT Window selector in the Instrument Options pop up menu to B Harris to select this windowing function See Figure 3 36 3 76 Reference Fast Fourier Transforms Time Window hee K i VAM p iy Nv ay Any npn AAA y 3 Frequency Filter Figure 3 36 FFT Magnitude Displayed Using Blackman Harris Window The Hanning Window The Hanning or Hann or cosine window is derived from a cosine This window provides reasonably good amplitude accuracy and leakage rejection Set the FFT Window selector in the Instrument Options pop up menu to Hanning to select this windowing function See Figure 3 37 4d Vn bay 4 VURAL MAL Time Window MW NAY MAN i MAMA MM op Le Figure 3 37 FFT Magnitude Displayed Using Hanning Window CSA 803A User Manual 3 77 Fast Fourier Transforms 3 78 The Hamming Window The Hamming window is similar to the Hanning window but is optimized to lower the first side lobe which is why the separation between the two spikes
92. the incident or the refiected edges will not match the steps at the end of the cable since the reflections had to travel back through unmatched cables as well As shown in Figure 3 98 to match the steps at the open end make the delay between the incident steps T1 equal but opposite in sign to the delay between the reflected steps T2 C Step 1 Press the WAVEFORM button and touch the Sampling Head Fne s selector O Step 2 Touch TDR A Delay and then adjust the knob For some measurements and comparisons you may want to visually line up the leading edges of both TDR steps even though you ve delayed the step assertion time for one channel To do this create a window of each trace and place each window trace in the lower graticule Then select one of the window traces and using the icon and the lower knob position the leading edge of the trace This does not affect the arrival of the TDR steps at the reference plane CH 1 CH 2 Refiected Pulses incident Pulses Set Ti T2 E T1 T2 Figure 3 98 Ensuring Pulses Arrive at the Reference Plane at the Same Time 3 200 Reference CSA 803A User Manual Time and Date The CSA 803A has an internal clock with battery back up that keeps track of the time and date You can set the clock using the Instrument Options pop up menu in the Utility1 major menu When you touch the Hours Minutes Seconds Month Day or Year selector one of the knobs i
93. the most accurate results use the shortest time per division that shows the points to be measured Window traces can be used to get a much shorter time per division and still have both cursor points on the display C Step 2 Leave either of these traces as the selected trace and note the number of the other trace Cl Step 3 Touch Cursors Cursor Type and Split Dots CJ Step 4 Touch the trace selector of the other trace that you want to place a cursor on If you ve forgotten its number the trace een appears in each selector Step 5 The cursors are now placed one on each trace Use the knobs to move the cursors to the two locations from which you want to meas ure time difference Then read the time difference At at the bottom of the display 3 33 Cursors 3 34 Reference Diagnostics The CSA 803A features a diagnostic system that performs comprehensive tests of the instrument This ensures you that your instrument is operating correctly A set of tests is automatically performed whenever the CSA 803A is powered on You can execute additional diagnostic tests at any time _ There are three categories of tests Power On Diagnostics are basic functional tests These ensure that the various microprocessors are running and communicating with each other The power on diagnostics take about 5 seconds to execute and are run only at power on NOTE The CSA 803A executes the power on and self test diagnostics whene
94. the trace M1 M2 if M1 has a vertical size of 50 mV div and M2 has a vertical size of 100 mV div the trace will have undefined vertical units You can select which channel of the trace you want to adjust with the knobs Whenever the icon is highlighted the lower right corner of the display shows the Chan Sel selector This selector always shows which channel the knobs are set to adjust You can touch this selector until it shows the chan nel you want to adjust with the knobs Adjusting High Precision Traces High precision traces use floating point arithmetic in their calculation When the selected trace is a high precision trace you will see High Prec in the bottom line of the Vertical Desc selector in the Waveform major menu You can adjust the vertical size and offset of high precision traces without adjusting a channel 3 220 Reference CSA 803A User Manual Vertical Controis NOTE See Trace Scaling on page 3 212 for a description of high precision traces When you adjust the vertical controls of a high precision trace the Chan Sel selector at the lower right of the display can be used to specify the individual channe to adjust and to specify the Calcd Tra or calculated trace When you specify that you want to adjust the calculated trace the knobs adjust the size and offset of the trace without changing the vertical size and offset of other traces displaying that channel Trace Separation When you adjust the v
95. trigger icon 7 at the left of the graticule shows not above it meaning the ad CSA 803A is not triggered This icon always shows you the trigger status The CSA 803A has an internal clock which is synchronized with the calibra tor output You will use this clock to trigger the trace To set triggering you need to use the Trigger major menu C Step 6 Press the TRIGGER major menu button in the MENUS column This displays the Trigger major menu The Source selector indicates that the current trigger source is the External Direct You need to change the source to Internal Clock CSA 803A User Manual 2 7 Example 1 Displaying a Trace Pop Up Menus Touching the Source selector demonstrates a common operation of selec tors they display pop up menus These menus are a temporary dialog with you they cover a portion of the graticule Most pop up menus disappear automatically when you make a selection Most pop up menus also provide an Exit or Cancel selector so you can remove them If you inadvertently display a pop up menu and wish to remove it you can also remove it by touching the selector that displayed the pop up menu This selector is highlighted during the time that the pop up menu is dis played Or you can touch a part of the graticule that has no traces on it C Step 7 Touch the Source selector in the major menu The Trigger Source pop up menu appears and the Source selector itself is highlighted see Figure 2 5
96. trols for optimum display m Vertical gain and offset and for calculated traces vertical size and position e Horizontal size and position Trigger level if appropriate to that trigger source CSA 803A User Manual 3 9 Autoset Undoing an Autoset If you don t like the results of an autoset you can restore the status of the CSA 803A by touching the Undo Last Autoset selector in the Instrument Options pop up menu of the Utility major menu See Figure 3 7 Autoset Options The instrument Options pop up menu lets you set several autoset parame ters so that you can tailor the autoset operation to your needs instrument Options Autaset Untians Figure 3 7 The Instrument Options Pop up Menu The Autoset Options section has five selectors to let you turn off or toggle certain autoset operations When you set the Vertical Autoset Horizontal Autoset or Trigger Autoset to Off those settings are not affected when you press the AUTOSET button For example if you set Horizontal Autoset to Off then the Horizontal Size or time per division setting is not changed when you next press AUTOSET The Enable All selector sets the other three selectors to their normal On state The exception to this is Standard Mask Autoset See Standard Mask Autoset on page 3 11 3 10 Reference CSA 803A User Manual Autoset The Autoset Mode selector lets you choose between Edge mode which shows a single rising or falling e
97. turn the screw shaft on the sampling head to tighten the head into place Sampling heads are described on page 3 169 _ Step 6 Connect the power cord from the POWER connector to your power system C Step 7 Set the PRINCIPAL POWER SWITCH to ON The PRINCIPAL POWER SWITCH controls ail AC power to the instrument The ON STANDBY switch controis power to most of the instrument s circuits but continues to supply power to certain circuits even when set to STANDBY 0O Step 8 To operate the instrument set the front panel ON STANDBY switch to ON Once the CSA 803A is installed use the ON STANDBY switch as the power switch 3 160 Reference Power On Sequence Warm Up Period CSA 803A User Manual Power On Each time you power on the CSA 803A the instrument performs a se quence of internal checks and then restores the settings that were in effect when the instrument was last powered off The sequence is I The power on diagnostics are performed and take about five seconds to execute If these diagnostics fail the instrument will freeze and you will not be able to operate it NOTE Complete descriptions of the diagnostics are on page 3 35 The self test diagnostics are performed and take about 15 seconds to execute If these diagnostics fail the extended diagnostic system is entered and the extended diagnostic menu is displayed The system restores all the settings and traces that it can If the configu r
98. value or a delta voltage from the refer ence baseline or reference topline The right limit of the measurement zone used in propagation delay and phase measurements on the reference trace The direction the waveform must pass through a reference level for the Prop Delay measurement The amplitude of a noise rejection band centered on the reference mesiai level Transitions through the reference mesial level are qualified by S N ratio by the requirement that the signal enter the noise rejection band and leave the noise rejection band at the opposite limit with the same slope and with no intermediate values outside the noise rejection band S N ratio may be set to any value from 7 to 99 The reciprocal of the number is the fraction of the peak to peak signal value that the noise rejec tion band extends above and below the reference mesial line For a 1 V peak to peak signal S N ratio of 20 creates a noise rejection band 0 05 V above and 0 05 V below the reference mesial level 3 153 Measurements 3 154 Table 3 12 Measurement Parameters Cont SW HW Stat Name al yo a Reference Topline Reference Tracking Reference Transition Number Right Limit Search Mode Definition The 100 level on which the reference mesial level is based When reference tracking is set to Both or Topline the CSA 803A repeatedly determines the reference topline for itself and you cannot adjust it When reference tr
99. 1 upper channel to be sampled by channel 2 lower channel a Step 9 Touch Sampling Head Fne s and touch Mainframe 2 under Selected Channel Touch TDR TDT to turn on the step generator for that channel The lower channel on each sampling head has an internal delay adjustment This iets you set the time at which the step generator for the lower channel asserts the TDR step Touch the TDR Head A Delay selector Then touch Exit to remove the pop up menu Reference CSA 803A User Manual TDR In step 9 you turned on TDR for the lower channel and you also assigned the knobs to adjust delay for the TDR step generator With some adjust ments the mainframe displays the two traces in Figure 3 97 Figure 3 96 Single Channel TDR 3 197 TDR 3 198 i 1 PRD Ee a 2 fo EOE IEE 3 g i H ETID G ieceri Pie Figure 3 97 Channels 1 and 2 TOR Notice that there are two rising edges on each trace On the upper trace the left most edge is the step transmitted by the step generator of the upper channe M1 The second rising edge is the step transmitted by the step generator of lower channel M2 On the lower trace the left most edge is the step transmitted by the step generator of the lower channel M2 The second rising edge is the step transmitted by the step generator or the upper channel M1 Note that both steps are positive This is equivalent to common mode trans
100. 3 Selecting Traces Using the Trace Status Menu 4 2 24 Labeling TAGS oso eve cases sates eeiniiee dae ies care eds 2 25 Displaying Dual Graticules 0 000 cece cence 2 27 Removing TraceS sessassossssnrusesznnssannsuesennn 2 29 Example 3 Defining Complex Traces cceeuerensnaes 2 31 Trace Expressions 2 sc 25chastada ssa is aa epn ENAT Uei 2 33 Vertical Adjustment of Complex Traces asssranineer 2 35 High Precision Traces cee cece nance eee oeeveeee 2 38 Windows os oes se al oe ene EEEE Ea eee 2 39 Horizontal Reference Point 05c00eeeceecssennneeos 2 41 Example 4 Using Signal Processing 0c0ecessceueess 2 43 Averaging and Enveloping s s esuusssaenrvsoussssess 2 45 Variable Persistence snusnsssnouenesansunorpwaanaso 2 48 SIMOOUUNG acd ie d orsina E hea eee ea E EEEE 2 50 R ord Lengitst essre siaaa ra in desea ea stave 2 51 Example 5 Taking Automated Measurements 2 0205006 2 53 Specifying Measurements 0 000 cence eee eee ewens 2 55 Measurement Parameters and Annotations 2 2 58 Default Measurement Parameters c00ceeeeeenneees 2 60 Measurement Modes 0 00cee cee eeeseaececeuenaes 2 62 Example 6 Taking Delay Measurements Using Cursors 2 67 The Cursors Major Menu ccc cence were wenenneee 2 68 Using Split Dot Cursors sisj 6cseweue ree weduw gon ed sawas ss 2 71 iv Contents Reference
101. 36 1 8662 Gb s OC48 STM16 2 4883 Gb s 3 134 Reference Mask Testing ANSI T1 102 Electrical Standard Masks Signal Requirements 75 Q signals require 75 50 converter with signal attenuation entered Table 3 8 ANSI T1 102 Electrical Standard Masks Mask Name Data Rate Trigger Data Signal Signal DSi 1 544 Mb s Same as data 100 Q B8ZS 100000001 00000001 000 0000 DS1 old 1 544 Mb s Same as data 1000 B amp ZS 100000001 00000001000 0000 DS1C 3 152 Mb s Same as data 100 Q B8ZS 100000001 00000001 000 0000 DS2 6 312 Mb s Same as data 1100 B6ZS 1000001000001 00000 DS3 44 736 Mb s Same as data 75 Q B3ZS 100100100 DS4NA 139 26 Mb s Same as data 75 Q CMI PRBS or live data DS4XNA 139 26 Mb s Same as data 75 Q CMI PRBS or live data STS1 51 84 Mb s Clock or data 75 Q PRBS or live data STS3 155 52 Mb s Clock or data 75 Q PRBS or live data STSX3 155 52 Mb s Clock or data 75 PRBS or live data Table 3 9 Miscellaneous Standards Masks Mask Name Data Rate Trigger Data Signal Signal FDDI Halt 125 Mb s Clock or data 11111000001111100000 1111100000 User Eye Programmable Clock ordata NRZ PRBS or live data CSA 803A User Manual 3 135 Mask Testing 3 136 Reference CSA 803A User Manual Measurements Measurements are numeric readouts of properties of a trace Measurements are updated continuously so that as the signal changes the numeric read outs change also You can select
102. 5 XY TACOS 22362 ices cues pee tee eka Deeds Renae 3 229 Appendices Appendix A Accessories 1 0 ccc cree erence een eens A 1 Standard Accessories ccc reece een cere eran nnneneee A 1 Optional Accessories 6 cc eee cece eee e eee nen A 1 Power Cord Options u usasesnnosssnsserosssnsreese A 2 Appendix B Specifications sassnrsssanonenrsresunuasa B 1 Appendix C Safety josey esse seeiwexd ia View enia Wee saa ESENE C 1 Symbols and TermS esis iswusad shawnee ede aires eee ees C i Specific Precautions ssssssnerorrrsnnnsssrsrrense C 2 Electrical Connections 00cc cence ncanneneoneeeecuees C 3 Packaging for Shipment 0 0cceee cence essere C 4 Appendix D Algorithms 5s iced coice Pied cece t es ores eves Be bees D 1 Trace Functions siris View sud eriaren aed rnea Aaa iee See D 1 Software Measurements essssssnsnoarassvsrsnnasso D 12 Statistical Measurements 20c cece cee ee eeeee D 23 Hardware Measurements essssssnnsnsesosossssoansus D 25 CGF GradiNg sedes eTa ru inanon i eT Ee aE EE a D 27 Appendix E Messages asesoesurorusisossssanssssssens E 1 Selected Message Descriptions susssesssnrnnanssao E 1 X Contents Glossary Index CSA 803A User Manual Table of Contents Glossary ee a cee Bees ae eane a A wie Cake alhee beod G 1 xi Table of Contents xii Contents CSA 803A User Manual Figure 1 1 Figure 1 2 Fi
103. ADelay assigns the knobs to set the delay between the TDR steps generated by the two channels of the sampling head TDR Preset turns on the TDR step generator selects Internal Clock trigger creates a waveform on the selected channel turns on rho scaling turns on baseline correction and autosets in edge mode the TDR step Diff TDR Preset performs the same actions as TDR Preset except it creates two channels of TDR with opposite polarities Preset Clear partially undoes TDR and Diff TDR settings by turning off TDR generators waveforms are not deleted and if no channels have TDR on trigger source is set to external trigger mode is set to Auto baseline correction is turned off and vertical scaling is set to Volts instead of rho 3 172 Reference Sampling Heads ie i i i teas i i H i i Status j i i i H i atL tus i j Figure 3 80 The Sampling Head Fnc s Pop up Menu External Channel Attenuation enables you to enter a number representing the external attenuation of a channel Once the number has been entered 1 is the default the instrument then uses the total attenuation factor in scaling measurement results Note that the attenuation factor is also applied to Vertical Size Total attenuation is the product of the external attenuation times the hard ware attenuation of the probe or sampling head The hardware attenuation factor is displayed in the Identify pop up menu of the Utility1 major menu
104. Acquisition You can limit acquisition based on either the number of waveforms or the number of samples or hits acquired in the histogram These functions are controlled by the Set N and Stop N selectors in the Persist Histograms pop up menu See Figure 3 49 3 102 Reference CSA 803A User Manual Histograms To limit acquisition based on the number of waveforms acquired display the Persist Histograms menu and touch Set N Waveforms This assigns the knobs to limit the number of waveforms acquired The range for the number of waveforms acquired is 1 to 282 1 approximately four billion To begin conditional acquisition touch Stop N Waveforms Acquisition will stop when N waveforms have been acquired The number of waveforms left to acquire is shown in the lower left corner of the display To limit acquisition based on the number of histogram hits first touch Set N Samples This assigns the knobs to limit the number of samples acquired Using the knobs set the number of samples you wish to acquire The range for the number of samples acquired is 1 to 2 1 approximately four bil lion To begin acquisition touch Stop N Samples Touching this selector starts acquisition which then continues until N samples have been acquired The number of samples left to acquire is shown in the lower left corner of the display Thus there are two steps to stop acquisition based on the number of sam ples acquired CJ Step 1 S
105. C connector you may also need to set the RS 232 C flagging to Hard Setting RS 232 C parame ters is explained on page 3 166 3 90 Reference Hardcopy Set the printing properties of the CSA 803A using the Hardcopy pop up menu in the Utility major menu See Figure 3 45 This menu includes selectors for seven types of printers and for specific options available with some printers Hardcopy Parameters anced Figure 3 45 The Hardcopy Pop up Menu Printer Selections The selectors in the Printer section of the Hardcopy pop up menu deter mine the printing configuration of the CSA 803A The settings of the other hardcopy parameters will vary according to the printer that is selected When you change one of these parameters you are setting its default value for the selected printer type These settings are not changed when you initialize the CSA 803A NOTE Printer selection and the associated parameters are not affected by initialization CSA 803A User Manual 3 91 Hardcopy u 8 Pin supports several eight pin dot matrix printers including the Tektronix 4644 Epson FX80 and Epson EX800 The IBM ProPrinter and Epson RX80 may also be used but only the HiRes screen format provides useful output for these printers All the supported printers typically use the PRINTER Centronics connector Set the configuration switches on your printer as recommended in its manual except set No Auto Line Feed No Perf Skip and Inb
106. CSA 803A presents a trace that is an average of several accumuiated trace records Each sample in a record is numeri cally averaged with the same sample in all the other records The result ing trace is displayed Enveloping shows the cumulative effect of noise over a period of time It is similar to averaging in that several trace records are accumulated and a combined result is displayed An enveloped trace shows the maximum excursions of the individual trace records This often results in a thicker trace that shows the limits of variation of the signal CSA 803A User Manual 3 13 Averaging and Enveloping Defining an Averaged There are two ways of establishing an averaged or enveloped trace or Enveloped Trace 3 14 1 If you are establishing a new trace you can use the AVG or ENV trace functions as you define your trace These can be selected from the Def Tra menu For more information on this method see Trace Definition and Management on page 3 203 2 The easiest method is to establish the trace first without averaging or enveloping Then after you have the trace adjusted you can invoke averaging or enveloping The following procedure describes averaging and enveloping using the second method described above C Step 1 Create the trace you want using any method NOTE If you aren t sure how to define a trace see Trace Definition and Management on page 3 203 C Step 2 If the trace isn t selected to
107. D 14 sampling head NOTE You should calibrate gain before calibrating offset Adjust the calibration value to set the trace exactly on the centerline of the graticule Repeat the process using a vertical size of 2 mV div You can set the knob resolution to fine adjust the calibration value more accurately You can also use waveform averaging or the mean measuremeni to calibrate offset null There are two offset values to calibrate manually normal sampling mode and smoothing mode Calibrate both separately by setting the sampling head in the desired mode before making the calibration Smoothing is selected from the Sampling Head Fne s pop up menu of the Waveform major menu Calibrating TDR Amplitude Manually To calibrate TDR amplitude manually first attach a 50 Q terminator to the sampling head channel you want to calibrate Establish a TDR trace show ing this channel with a vertical size of 50 mV div and a horizontal size of 1 ns div Touch the vertical icon and the Vert Offset knob label selector to show the Numeric Keypad pop up menu On the pop up menu touch 0 and Enter This sets the vertical offset to zero positioning 0 V at the center height of the graticule Center the rising edge of the pulse horizontally on the graticule Adjust the calibration value to set the height of the first part of the trace exactly at the bottom TDR Polarity or top TDR Polarity of the graticule There are two TDR Amplitude value
108. DAC Not Data Accepted is lighted whenever a data byte is on the bus but has not yet been captured by any listener device GPIB Area Figure 3 39 GPIB Rear Panel Connector and Lights CSA 803A User Manual 3 79 GPIB Parameters i Communication between the devices on a GPIB bus can occur only if ail bus Setting GPIB Parameters devices are configured in a compatible manner For example each device on the bus must have a unique identifying address Use the GPIB RS232C pop up menu in the Utility major menu to set these GPIB parameters directly before you attempt to communicate with other devices on the bus See Figure 3 40 noted Heocuracy Figure 3 40 The GPIB RS232C Pop up Menu The following list describes each selector in the GPIB Parameters section of this pop up menu Mode lets you set the mode to either Talk Listen Talk Only or Off Bus Off bus effectively disconnects the CSA 803A from the bus The CSA 803A must be in talk listen mode to communicate with a controller using the GPIB Talk only can be used to drive a printer or plotter over the GPIB NOTE GPIB parameters are not changed when you initialize the CSA 803A Address assigns the knobs to the GPIB address of the CSA 803A The GPIB address can be from 0 to 30 No other device on the bus can use the address that you assign to the CSA 803A 3 80 Reference CSA 803A User Manual GPIB Parameters Terminator
109. DDI 100 baseline topline or SONET 10x log10 topline baseline The vertical dispersion of a trace Available in Statistics mode only The noise measurement can be taken at the topline or baseline The amplitude divided by the noise Noise is always calculated as RMS for this measurement regardless of how the Dispersion parameter is set The amplitude is equal to the baseline subtracted from the topline Noise is measured at the topline or baseline depending on how the noise location parameter is set This measure ment is only available in Statistical Measurement mode Reference CSA 803A User Manual Measurements Table 3 10 Measurements Cont Selector Measures Timing Measurements Rise The transition time of a rising pulse edge Fall The transition time of a falling pulse edge Frequency The reciprocal of the period Period The time taken for one compiete signal cycie PropDelay The time between mesial crossings of two different traces or two points on the same trace Cross The time from the trigger point to a specified level i crossing Width The time the signal takes to go from a voltage level crossing to the next crossing of the opposite slope Duty Cycle The percentage of a period that a waveform spends above the mesial Phase The phase angle from the selected waveform to the reference waveform Jitter The horizontal dispersion of the trace Available in Sta tistics mod
110. ENO ST Figure 2 54 TDR Step and Reflection 2 91 Example 10 Taking TDR Measurements Changing Graticule Units for TDR 2 92 Under normal operation the graticule units of measurement are volts for the vertical axis and seconds for the horizontal axis These are not the units of measurement commonly used in TDR When you selected TDR Preset the CSA 803A automatically changed the units of the vertical axis to units of rho p You can change the measure ment units for both graticule axes by using the Graticules selector in the Waveform major menu C Step 8 Touch Graticules in the major menu and Feet Meters or Inches in the pop up menu If you know that the propagation velocity of your cable differs from the default touch the Propagation Velocity selector and adjust this parameter If you don t know the velocity or are using Tektronix SMA cables accept the 0 7 default This unitless number represents the fraction of the speed of light that signals pass through your network or transmission line The horizontal axis is now calibrated in your chosen units of measurement NOTE Cursor readouts and measurements when appropriate are ex pressed in the same units as the graticule axes Observe the Y Units section of the Graticules pop up menu The vertical axis units are set to rho so Rho is selected in addition the Reference Amplitude selector shows a reference amplitude of 250 mV This is the amplitude of the step t
111. ETTINGS button on the front panel You can use that button to i change from one instrument setting to the next See page 3 179 PERANAN hh O EE E E EEEE E This pop up menu fets you store an instrument setting See page 3 176 CSA 803A User Manual 1 23 At a Glance Delete stored traces using this pop up menu See page 3 184 gt el ts O O EE EAEE E PEO OEE S CEEE E O E Clear displayed traces using this pop up menu See page 3 5 Steres Traces Moin Main TRIGGER MEASURE DISPLAY MODES STORE RECALL UEHATY These pop up menus let you recall or delete settings See page 3 177 f Tao oer nt we fe fe eee a a z TO Ta J i ere ir re eee ee aed Tein ee eg Spa eye gee ere are gt ajo oee a i Setting FPS setting FFS j TE Sa a ye t d i i i i i i i i i i j i H i i i i bee ajani o EN NEENA N NO N N N a i i Aa 1 24 Getting Started At a Glance Utility Major Menu This pop up menu shows instrument and sampling head identification and firmware version numbers See page 3 187 Exeoutive Display Use this pop up menu to set GPIB and RS 232 C parameters Time E See page 3 80 for GPIB and page 3 166 for RS 232 C EEEE Sampiing MY ix Meo ix Eb e4 i Ma GX M gt GX i Options i Telecomm Standard Mask
112. External attenuation can be specified either as a scaling factor 2 5 10 etc or in decibels dB Decibels dB is related to the attenuation factor by the formula dB 20 x log attenuation factor The range for dB is 120 to 120 Negative dB values or fractional attenuation factors indicate gain rather than attenuation External channel attenuation is a feature of the mainframe not of the sam pling head Thus this feature applies to all sampling heads CSA 803A User Manual 3 173 Sampling Heads 3 174 Smoothing Smoothing is processing applied by the sampling head prior to the digitiza tion of a trace to reduce noise When smoothing is on the sampling head samples each trace sample or dot eight times before going on to the next dot The average of the eight samples is digitized as the dot value in the trace record NOTE ff you turn on smoothing for one channel of a dual channel sam pling head both channels are smoothed You turn smoothing on or off with the Smoothing selector in the Sampling Head Fne s pop up menu Not all sampling heads provide smoothing so Smoothing may not be selectable in some cases Channel A Delay Channel A Delay adjusts the time delay of the channel 2 acquisition the lower channel with respect to the channel 1 acquisition the upper channel on sampling heads equipped with this feature lf you change Channel A Delay you should also adjust offset Refer to Adjusting
113. F decreases When the effective sample rate increases due to a faster horizontal size setting Fina and SF both increase giving the FFT trace a broader frequen cy range with less frequency resolution When you touch the vertical icon the knobs are assigned to control Vertical Mag Tra and Vertical Pos Tra the vertical magnitude and position of the trace As with other calculated traces the vertical controls of the FFT trace affect only the appearance of the trace 3 69 Fast Fourier Transforms FFT Scaling The FFT magnitude display may be scaled in either a linear or decibel format To set the vertical scaling of the FFT magnitude display select the FFT Scaling selector in the Instrument Options pop up menu in the Utility major menu See Figure 3 30 This selector toggles between Linear and dBm When FFT Scaling is set to dBm the display is in decibels relative to a 0 316 V peak sine wave 0 dBm into 50 Q If you want to display the FFT magnitude of a trace in dB relative to a specif ic reference you can subtract your reference value from the FFT magnitude of the trace when you enter the FFT trace description For example enter FFTmag Mt 10 to display the FFT magnitude of the signal at channel one relative to a 10 GB reference The FFT Scaling Selector Figure 3 30 The instrument Options Pop Up Menu 3 70 Reference Fast Fourier Transforms Aliasing occurs when the input signal inclu
114. FORM TRIGGER MEASURE DISPLAY MODES STORES RECALL UTILITY Graticule and axis unit controis See page 3 83 CSA 803A User Manual 1 19 At a Glance Trigger Major Menu Select the trigger source using this pop up menu See page 3 213 Trigger Sources ko Touch this selector to Touch this selector to assign enable disable high the knobs to control trigger frequency holdoff level See page 3 273 See page 3 213 WAVEFORM TRIGGER MEASURE DISPLAY MODES STORE RECALL UTILITY Select Normal or Auto Touch this selector to Trigger with this selector enable enhanced See page 3 213 triggering See page 3 213 Touch this selector to change the trigger slope See page 3 273 Set trigger holdoff parameters using this pop up menu See page 3 273 1 20 Getting Started Ata Glance Measure Major Menu Meagurements Use this pop up menu fo specify which measurements you want to take As you select measurements the readouts appear immediately in the unused selectors of the major menu See page 3 141 aches Gmplitude Timing Areaineray Touch a measurement readout to display a pop up menu that lets you control the way the measurement is taken See page 3 149 egioma ire WAVEFORM TRIGGER MEASURE DISPLAY MODES STOBE STORE These six selectors are reserved for the readouts o
115. GER button Touch the Source selector in the Trigger major menu Touch External Direct Touch Exit to remove the pop up menu C Step 6 Select channel 1 by pressing the select channe button next to the input connector on the sampling head L Step 7 Press the AUTOSET button The signal may not be recogniz able at this point CJ Step 8 Because the signal is a random pulse train the horizontal size cannot be properly autoset Adjust the horizontal size to display a useful eye diagram See Figure 3 26 3 61 Eye Diagrams NOTE Eye Diagram Analysis can be reliably performed on signals up to 400 mV peak to peak in amplitude Signals larger than 400 mV in amplitude should be attenuated to achieve reliable results in Eye Diagram Analysis in antinucuel gt 3 lt i Si Figure 3 26 An Eye Diagram Display O Step 9 One way to enhance the display of the eye diagram is to use Variable Persistence To do this press the DISPLAY MODES button touch the Persist Histograms selector touch the Variable selector in the pop up menu and then touch Exit to remove the pop up menu For additional information on variable persistence see Setting the Persist ence Mode on page 3 44 3 62 Reference CSA 803A User Manual Eye Diagrams O Step 10 One of the most powerful display modes in the CSA 803A is color grading Color grading adds statistical information to the display by varying the color according to the number
116. Horizontal Controls Pan Zoom allows you to magnify any portion of the selected trace to exam ine it more closely You can magnify zoom the selected trace to the point where each digitized sample appears on the display and you can move the magnified trace left and right pan to examine any part of the trace The maximum magnification is determined by the trace record length which is described in the Record Length section page 3 163 The trace display area is 512 pixels wide so you can magnify a 5120 point trace up to 10 times A 512 point trace already displays only one digitized sample per pixel and cannot be magnified NOTE Pan Zoom does not change the way trace data is sampled and recorded It only changes the way the trace data is displayed Whenever the lt icon is highlighted the lower right corner of the display shows the Pan Zoom selector Normally Pan Zoom is off and the knobs are assigned to horizontal size and position When you touch the Pan Zoom selector to set it on the knobs are assigned to Horz Mag Zoom and Horz Pos Gr Pan You use the top knob Horz Mag to specify how much magnification you want on the selected trace You use the bottom knob Horz Pos Gr to position the segment of the trace that you want to view onto the display The knob label status area shows how many trace data points are not shown because they are off the left end of the screen When you set Horz Pos Gr to zero you display the left
117. LAY MODES STORE RECALL UTILIFY CSA 803A User Manual Use this selector to initiate a self test and verify that the instrument is operating properly See page 3 38 Use this selector to enter the extended diagnostics system See page 3 38 Use this selector to return to the Utility major menu See page 1 25 Ata Glance 1 29 At a Glance 1 30 Getting Started Overview This section presents ten examples that illustrate how to use the CSA 803A Communications Signal Analyzer Examples 1 through 4 describe how to define and display single and multiple traces and how to perform signal processing Examples 5 through 7 describe how to take automated measurements how to use measurement annotations to control the measured portion of the trace how to select from the three types of measurements software statis cal or hardware and how to use a reference trace for comparison measure ments Examples 8 through 10 discuss advanced features of your CSA 803A Com munications Signal Analyzer that are beyond the standard set of oscillo scope features These examples cover using a stored trace as a reference taking histograms of displayed trace data and taking Time Domain Reflecto metry TDR measurements Example 1 Displaying a Trace Example 2 Managing Multiple Traces a Example 3 Defining ComplexTraces a Example 4 Using Signal Processing a Example 5 Taking Automated Measurements a Example
118. Mesial or Eye Cross lf the CSA 803A does not recognize the signal as an eye diagram only Mesial is available a a Left Limit The beginning of the trace measure ment zone al va al Level Mode In absolute level mode you set proxi mai distal mesial and reference level in absolute voltage values In relative level mode you set these parameters in terms of percentages of the baseline to topline distance In delta level mode you set a deita voltage with from the baseline or topline al al al Mesial The middie voltage level expressed as a percentage of baseline to topline dis tance May be set as a relative percent value an absolute volts value or a delta voltage from the baseline or topline 1 Noise The location of the histogram for the Location Noise measurement May be Baseline or Topline al Peak Index For frequency domain measurements used with the Peak search mode See Search Mode below val in Pad Proximal The proximal closest from origin volt age level Rise and fali times are meas ured between the proximal and distal voltage levels which are typically 10 and 90 of the baseline to topline volt ages May be set as a relative percent an absolute volts value or a delta volt age from the baseline or topline a al i Reference The reference baseline value is the 0 Baseline level on which the reference mesial level is based When reference tracking mode is set to Both or Baseline t
119. OSET button to display a portion of the trace at this horizontal setting Step 7 Press UTILITY and touch Instrument Options Touch Horizon tal Autoset until the selector shows Off and touch Exit 0O Step 8 Press the AUTOSET button The display should appear as shown in Figure 2 28 S4dm cP gy a a ee Sa BBHLens ipsdiv S0 1 12ns Figure 2 28 A Horizontally and Vertically Expanded Portion of the Calibrator Signa 2 44 Operating Basics Averaging and Enveloping CSA 803A User Manual Example 4 Using Signal Processing An averaged trace is one where several trace records successive trace acquisitions are combined Each displayed point of the resulting trace is an average of all the same points in the individual records This can reduce the noise of the trace and increase vertical resolution Enveloping is similar in that several trace records are collected Instead of a single point average the envelope dispiays the maximum and minimum excursion of the samples This shows the accumulated variation of the signal The DefTra pop up menu has Avg and Env selectors Typically an aver aged trace expression Avg M1 would be entered with the selectors DefTra Avg 1 Enter Desc A short cut is available to apply averaging or enveloping to an existing trace expression The Waveform major menu s Acquire Desc pop up menu provides Average N and Envelope N selectors to set these functions on and off see F
120. On installation Before you first power on your CSA 803A you should make certain it is correctly installed The installation sequence involves the following controls connectors and switches on the rear panel see Figure 3 72 m POWER Connector w FUSE m LINE VOLTAGE SELECTOR switch w PRINCIPAL POWER SWITCH Power Area ia N Figure 3 72 Power Connector Fuse and Switches In addition you will need to know the location of the ON STANDBY switch on the front panel see Figure 3 73 The ON STANDBY Switch ACQUISITION aroser manpcopy SEQUENGE RuN s a ae I J Figure 3 73 Front Panel ON STANDBY Switch CSA 803A User Manual 3 159 Power On The following steps describe the installation procedure for the CSA 803A Step 1 Set the PRINCIPAL POWER SWITCH to OFF C Step 2 Set the front pane ON STANDBY switch to STANDBY Step 3 Set the LINE VOLTAGE SELECTOR to the proper range for your power system C Step 4 Check the FUSE to be sure it is of the proper type and rating as printed on the rear panel E Step 5 With a grounding wrist strap properly attached to your wrist and connected to the antistatic connector on the front panel of your instru ment install one or more sampling heads in the front panel compart ments Never install or remove a sampling head with the CSA 803A power on To install a sampling head place it into a compartment and push it tn with firm pressure Once it is seated
121. Processing This example shows how you can process your signals to get the most information from the available data You will simulate a noisy signal by examining part of the calibrator signal at very fine horizontal time per division and vertical volts per division set tings NOTE The amount of noise you see in this example will depend on the sampling head you have installed For this example you will need a CSA 803A with at least one sampling head installed one SMA cable and one static protection wrist strap CJ Step 1 Initialize the CSA 803A press the UTILITY button in the MENUS column touch Initialize in the major menu and touch Initialize in the verification pop up menu L Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A C Step 3 Connect the CALIBRATOR output to any sampling head input j wd wd C Figure 2 27 Connections for Example 4 C Step 4 Press the SELECT CHANNEL button nearest the sampling head input you have connected to the calibrator C Step 5 Press the TRIGGER button in the MENUS column touch Source in the major menu and Internal Clock in the pop up menu Touch Exit to remove the pop up menu CSA 803A User Manual 2 43 Example 4 Using Signal Processing 0 Step 6 Turn the top knob to the right until the horizontal scale is 1 ps div By turning off horizontal autoset you can use the AUT
122. Programmer Reference describes using a compuier to control the CSA 803A through GPIB or RS 232 C interfaces The CSA 803A Service Reference provides module level repair and replacement information about the CSA 803A This manual applies to the CSA803 and CSA803A Communication Signal Analyzers that are equipped with firmware Version 4 or later for the Executed Processor Display and Timebase Controller See System Identification in the Reference section of this manual for information about obtaining the firm ware version number Note that the following features described in this manual do not apply to the CSA803 Communications Signal Analyzer High Frequency On Off selection see Triggering in the Reference sec tion of this manual m Enhanced Triggering On Off selection see Triggering in the Reference section of this manual User adjustable Trigger Holdoff see Triggering in the Reference section of this manual Refer to Appendix B for specifications for the CSA803 Communications Signal Analyzer About This Manual ii About This Manual Getting Started CSA 803A User Manual LIST OT FIGUIOS i 26 iid txceeee eee eee dion taeda td ieee laseceiaes List of Tables introduction Table of Contents RANKER RRR ARE heh ese cme aee see ce cea ee eee em eee er yR CSA 803A Description 6 2 e cece eee eee eens Description of Sampling c cece nn eneneeeeeeeee Safet
123. RMS selector again in the major menu area The annotation lines remain and you can see ail of the display If you wish to remove these annotation lines push a different major menu button or select a different trace by touch For now closely examine the RMS pop up menu see Figure 2 37 C Step 13 Touch the RMS selector a third time to redisplay the menu At the bottom of the menu non selectable readouts show the Mean Stan dard Deviation and Current N the number of samples the statistics are based on A Set N selector lets you assign the knobs to control the N value This N value is shared by all measurements on the selected trace so if you change the N value of the RMS measurement it will change the frequency measurement N value as well NOTE Changing a parameter affects all measurements that use that parameter on the selected trace C Step 14 Touch the Set N selector and turn either knob observing the change in N You can change measurement parameters without the pop up menu in the way An example is the measurement limits when the pop up menu is present you can t see these vertical lines The measurement limits define the portion of the trace that the measurement system is limited to examining 2 58 Operating Basics Example 5 Taking Automated Measurements Mein DADIE Se Figure 2 37 The RMS Pop Up Menu and Annotation Lines C Step 15 Touch either the Left Limit or Right Limit
124. Reference Labeling You can label active traces stored traces and stored settings for easier identification A label is a string of up to ten letters numbers or spaces that appears next to a displayed trace or as part of a trace or stored setting selector in menus See Figure 3 55 shme SM ouio it i y Pasi m SL ne eel Sat NN ia ee to SEDAN Hatt EON abr Maanam aynen an E N A eth T erot asan n M araen Ai 4 te cecal EA AA mmaa SEIAT SH IES EEA SLR MOR IERPS SOP Bin gt fem panenan isea trin d 3 hilasi Snsvdiv Figure 3 55 Labels Displayed with Active Traces CSA 803A User Manual 3 115 Labeling Creating Labels You can create and edit labels by using the Labeling pop up menu shown on the next page Select Labeling in the Utilityi major menu to display the pop up menu The uppermost section of this menu contains selectors for Displayed Traces Stored Traces and Stored Settings Beneath these selectors the selectors for individual active traces stored traces or stored settings appear if there are more stored traces or stored settings than can be displayed at once use the Paget and Page selectors to scroll through the menu To create or change a label select the item you want to label from the Labeling pop up menu shown in Figure 3 56 For example select Stored Trace Then select the stored trace you want to label You can then type the label by touching the character selectors
125. Reference section of this manual The bottom knob similariy controls the window record lengths You should be aware of the following attributes of record lengths a Ail main time base traces share the same record length a All window traces share the same record length a Initialize sets both record lengths to 512 Variable persistence infinite persistence and color grading are available only for traces with a 512 point record length Selecting one of these modes automatically sets the record length to 512 The 4096 record length has the same resolution as a 5120 record length but appears as a shorter trace Some FFT and other signa processing algorithms running on external computers require record lengths that are exponential multiples of 2 The 4096 record length is provided for these applications The visual truncation is the result of a shorter record using the same resolution as the 5120 record length CSA 803A User Manual 2 51 Example 4 Using Signal Processing 2 52 Operating Basics Example 5 Taking Automated Measurements This example demonstrates how quickly you can display a dynamic meas urement from a displayed trace For this example you will need a CSA 803A with at least one sampling head installed one SMA cable and a static protection wrist strap The first step in taking a trace measurement is to achieve a good display of the trace C Step 1 Initialize the CSA 803A press the UTILITY butt
126. Select channel 2 by touching it You can determine which channel is selected by the yellow blinking light next to the input connector Step 13 Press the WAVEFORM button Step 14 Select Horizontal Desc from the major menu Step 15 Touch the Trace 2 selector in the XY Display Mode section of the pop up menu if a 45 line appears instead of a constellation diagram you have se lected the wrong trace as the X component This results in plotting one channel against itself which produces a diagonal line instead of a constellation diagram To select the correct channel go back to the Horizontal Desc pop up menu and select the other non highlighted channel in the XY display mode section of the pop up menu See Fig ure 3 13 3 27 Constellation Diagrams SAB ny AEn Figure 3 13 The Display After Selecting the XY Display Mode 0 Step 16 The channel 2 trace should now appear as a constellation diagram and the channel 1 trace should remain unchanged Now delete the channel 1 trace touch the other signal display and use the Remove Cir pop up menu and adjust the constellation diagram to fill the screen To enlarge the constellation diagram adjust the size and position con trols as necessary You should now have a constellation diagram in the center of the screen You can now use histograms mask testing variable persistence and color grading to evaluate the constellation diagram 3 28 Reference Cu
127. T prase K scrtan 7 where A k real part of X k Bk imaginary part of X k The magnitude and phase for negative frequencies are discarded and linear interpolation is used to expand the positive frequencies to fill the entire record length The magnitude of the frequency spectrum in decibels is given as FF T magan k 20log F p T maelk where the 0 dB point is defined as the sine wave of 0 316 V peak 0 224 Vans which gives 1 0 mW into 50 Q FFT Windowing Functions The selected FFT windowing function is applied to the time domain wave form before the FFT is computed The FFT windowing functions are as follows Rectangular R 1 xn 1 n G a Triangular R R 2 xn p 2 25 R 25 a 0 Hanning R 1 x 05U cos 2a4 n 0 R E Hamming R i x n 0 54 0 46 1 cos 2m P n 0 Appendices CSA 803A User Manual Appendix D Algorithms a Blackman R i x n ge 0 5 cos 2 0 08 cos n g n a Blackman Harris x n p a 9 35875 0 48829 cos 2n 0 14128 cos n p 0 01168 cos 6x where R the record length which must be a power of 2 The filter characteristics of the FFT windowing functions are summarized in Table D 1 These numbers are taken from a table in Frederic J Harris Handbook of Digital Signal Processing edited by Douglas F Elliot Academ ic Press San Diego 1987 pp 254 255 Table D 1 Filter Characteristics of FFT Window
128. TILITY button in the MENUS column touch Initialize in the major menu and touch Initialize in the verification pop up menu C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A O Step 3 Connect the CALIBRATOR output to any sampling head input l d l ed l Cj Figure 2 50 Connections for Example 9 C Step 4 Press the TRIGGER button and touch Source and Internal Clock then touch Exit C Step 5 Press the SELECT CHANNEL button on the sampling head input channel to which you have connected the calibrator E Step 6 Turn the top knob to the right until the horizontal scale is 1 ps div g Step 7 Press UTILITY and touch instrument Options Touch Horizon tal Autoset until the selector shows Off and touch Exit C Step 8 Press the AUTOSET button 2 85 Example 9 Creating a Histrogram Display In Example 4 you used color grading to view the relative density of trace points in a display of this signal A histogram will provide additional statisti cal information about the distribution of points in the trace L Step 9 Press the DISPLAY MODES button and select Persist Histo grams in the major menu area C Step 10 Select Vertical Histogram in the pop up menu and then select Exit When you selected Vertical Histogram the display persistence automatical ly changed from Normal to Infinite Histograms can be displayed on traces
129. United Kingdom 240 V 6A 50 Hz Tektronix part number 161 0066 10 Option A3 Australian 240V 6A 50 Hz Tektronix part number 161 0066 11 Option A4 North American 250 V 10A 60 Hz Tektronix part number 161 0066 12 Option A5 Switzerland 240 V 6A 50 Hz Tektronix part number 161 0154 00 Appendices CSA 803A User Manual Appendix B Specifications The CSA 803A electrical characteristics apply to the following conditions a The instrument has had a 20 minute warm up period a The instrument is operating in an environment that meets the limits described in Environmental Specifications in this section The specifications in Tables B 1 through B 7 apply to the CSA 803A Com munications Signal Analyzer only See Tables B 8 through B 14 for specifi cations for the CSA 803 Table B 1 CSA 803A Vertical System Specifications Characteristic Specification input sources Mainframe Bandwidth Risetime Amplifier gain accuracy Vertical resolution Trace data Hardware measurements Input sensitivity Offset accuracy Offset range Offset resolution Measurement leve accuracy Vertical acquisition resolution Singie graticule Dual graticule Vertical display resolution Single graticule Duai graticule 2 sampling heads 4 channels Dependent on sampling head Dependent on sampling head 1 of full scale range 8 bits 14 bits 2 mV div to 255 mV div in 1 mV div steps 2 mV 2 V 0 25 mV 2 mV
130. X and the bottom knob is assigned to Mask Cursor Y deiined Figure 3 60 The Mask Testing Pop up Menu To add a point to a mask use the cursors to locate the cross hair cursor over the location where you want to add a point Touch Add Point To delete a point from a mask locate the cursor over the point to be deleted Touch Delete Point When you are finished creating the mask touch Exit Mask Editing See Figure 3 61 3 124 Reference Mask Testing Figure 3 61 Editing a Mask Masks are created by connecting the points independent of the order they are entered Points are connected by sorting the points into left to right order and grouping them across a diagonal from the left most point to the right most point If two points share the same horizontai position along either the left or right edge of the mask then the diagonal runs from the top left most point to the bottom right most point Points below the diagonal form the bottom boundary of the mask points above it form the top boundary Thus it is difficult to make masks that have concave sides See Hints for Creating Masks below The illustrations on the following pages show how mask points are con nected when you edit a mask Deleting User Masks To delete a mask first display the Mask Testing menu Select the mask to delete by touching the MaskN selector and then touch Delete Mask Definition CSA 803A User Manual 3 125 Mask Testing Hint
131. a User Mask 0 00 cee cece c ewes 3 128 Creating a New Mask From a Standard Mask 3 128 Creating a User Eye Mask 00 0 cece eee c cece ence 3 128 Starting Mask Testing 20 c cece seer ee eer enenene 3 130 Clearing the Hit Count lt c scncacdatnetaernaaew ed a oowe 3 131 Limiting ACOUISMON 3 s ecae yee ibe eodnet a towdusek Gadd 3 131 Standard Mask Definitions and Requirements 3 133 CCITT G 703 Electrical Standards Masks 3 133 ANSI SONET CCITT SDH Optical Standards Masks 3 134 ANSI T1 102 Electrical Standard Masks 3 135 Measurements sessie ase ewe de dee kad oak dake ea eens ve 3 137 Setting Up Measurements 0 0c cece rene ee eens 3 140 Deleting Measurements 0 cccccee ec ece ee cseuccees 3 142 Topline Baseline Calculation cceeeveseereuueeae 3 142 Measurement Mode 0 0cccce ee eeaeeeseeeeneaces 3 143 Frequency Domain Measurements 0 50 3 143 Statistical Measurement Considerations 5 3 144 Comparing Measurements to References 3 147 Changing Measurement Parameters 00e000e 3 149 Measurement Statistics 2 cence eee ee cen nneeeeacn 3 156 Changing Default Parameters cceeeueeceeeeuce 3 157 POWOD Sodvise se eerie E aaueuee blames cient tu einen ey 3 159 Installati n pas chs cen thse hGeeaa ea Renew ew A Nah eke E Ea
132. a high level view of the CSA 803A Communications Signal Analyzer and its features The CSA 803A Communications Signai Analyzer provides unprecedented capabilities in capturing and accurately measuring high speed electrical events Some of the main features of the CSA 803A are w Fast rise time and wide bandwidth as determined by sampling head m Sweep speeds from 1 picosecond per division to 5 milliseconds per division adjustable in calibrated 1 picosecond per division steps 200 kHz sampling rate for high system throughput and real time dis pilay a Digital trace capture display and storage Provides a bright stabie display even with signals of low repetition rate m Traces are captured with 8 bit vertical resolution and can have from 512 to 5120 points each Simultaneous display of up to eight traces Each trace can represent a single input channel or a complex expression that mathematically combines multiple input channels or an expanded window of another trace m Time or voltage histograms displayed on screen and updated continu ously as trace data are collected w Mask testing for easy go no go testing and error rate measurements m Standard mask testing using a library of 38 predefined telecommunica tion masks Option 11 Color grading provides a third dimension sample density to displayed data and allows histogram and mask analysis after collecting data m Full function trigger up to 3 0 GHz wi
133. aced by the Trace Status major menu though the light beside the WAVEFORM button remains lighted This menu shows one seiector for each displayed trace You can select any trace by touching its selector The selector for the selected trace is always highlighted The Return to Single Trace selector restores the regular Waveform major menu See Figure 3 101 3 208 Reference Modifying Traces Trace Definition and Management Figure 3 101 The Trace Status Menu Selecting Traces Using the Sampling Head Channel Button You may want to select a trace that displays a specific sampling head chan nel lf that sampling head channel is not already part of the selected trace you can press the Select Channel button on the sampling head You can look at the channel light on the sampling head to determine if that channel is part of the selected trace If the light is on and blinking then the channel is part of the selected trace and pressing the channel button will remove the selected trace If the light is on and not blinking that indicates that the channel is displayed but is not part of the selected trace Pressing the channel button wiil select a trace that contains that channel You can change the trace expression of the selected trace When you touch the Vertical Desc selector in the Waveform major menu the Vertical Desc pop up menu is displayed This menu is identical to the pop up menu that is displayed when you touch the DefTra i
134. ach trace by touch and observe the Vertical Desc and Remove Cir Trace n selectors and the sampling head lights 2 23 Example 2 Managing Multiple Traces Selecting Traces Using the Trace Status Menu 2 24 Another method of selecting traces presents information about all displayed traces simultaneously The Waveform major menu has an alternate Trace Status menu as shown in Figure 2 17 The WAVEFORM button is lit when either alternative is displayed The More selector of the standard Wave form major menu displays this alternate O Step 17 Touch the More selector in the major menu to see the Trace Status menu Figure 2 17 The Trace Status Menu The Trace Status menu has a Return to Single Trace selector to return you to the normal Waveform major menu or just press the WAVEFORM major menu button The Trace Status menu presents one selector for each displayed trace These selectors show status information about the trace they represent The selector for the selected trace is highlighted You can make any trace the selected trace by touching its selector This highlights the new trace and the representative selector in the Trace Status Menu C Step 18 Touch the trace selector that is not highlighted Notice that it becomes highlighted and that its trace is brightened on the graticule C Step 19 Return to the normal Waveform major menu either by touch ing the Return to Single Trace selector in the major menu
135. ack ing is set to Baseline or Off you can set the topline or you can have the CSA 803A set it once by touching the Setup selector The track mode on the reference trace for propagation delay and phase mea suremenis The transition number on the reference trace used in propagation delay and phase measurements The end of the trace measurement zone For frequency domain measurements When search mode is set to Harmonic the instrument determines the funda mental frequency f0 by searching for the highest peak of the FFT magnitude in the measurement zone The harmon ic components are computed as n xf where n is the user defined harmonic number When search mode is set to Peak a spectral peak is defined as a peak of the FFT magnitude greater than the ref erence level Using the pop up menu you can specify the index of the peak to be measured and the reference level Reference Measurements Table 3 12 Measurement Parameters Cont SW HW Stat Name Definition uw S N Ratio val val 1 Second Trace i al i Slope al 1 a Topline a a a Tracking al Transition Number The amplitude of a noise rejection band centered on the mesial level Transitions through the mesial level are qualified by S N ratio by the requirement that the signal enter the noise rejection band and leave the band at the opposite limit with the same slope and with no inter mediate values outside the noise rejec tion band
136. acquired You can save time using Color Graded mode because the trace data doesn t need to be cleared CSA 803A User Manual 2 87 Example 9 Creating a Histrogram Display You can also control the number of samples the CSA 803A uses to develop the histogram Using the Persist Histograms pop up menu you can set a number of waveforms traces or a number of samples individual trace record points or hits to acquire for the histogram before stopping acquisition C Step 14 Touch the Persist Histograms selector to redisplay the pop up menu 0O Step 15 Touch Set N Samples to assign the knobs to control the number of samples for the histogram _ Step 16 Turn either knob to set the Sample N value C Step 17 Select Stop N Samples in the Persist Histograms pop up menu Trace acquisition stops when the number of Hits listed in the major menu area is equal to the number of samples you set 2 88 Operating Basics CSA 803A User Manual Example 9 Creating a Histogram Display This example demonstrates how you can create a histogram of a displayed trace As in Example 4 you will display the calibrator signal at very fine horizontal time per division and vertical volts per division settings to simulate a noisy signal For this example you will need a CSA 803A with at least one dual channel sampling head installed one SMA cable and a static protection wrist strap C Step 1 Initialize the CSA 803A press the U
137. acquisition is stopped The stop condition can be satisfied by N overflows in one bin and or one over flow in N bins that is the total number of overflows in all bins To stop acquisition after a set number of overflows touch Set N MaxContrast This assigns the knobs to limit the number of overflows allowed before the digitiz er is stopped The range for the number of overflows is 1 to 65 535 To begin acquisition touch Stop N MaxContrast Touching this selector starts acqui sition which then continues until the specified number of overflows have occurred When the number of overflows have occurred acquisition stops Thus there are two steps to stop acquisition based on the number of over flows C Step 1 Set the number of overflows used to limit acquisition by touch ing Set N MaxContrast and using the knobs 0O Step 2 Begin the acquisition by touching Stop N MaxContrast If you want to stop the acquisition while still acquiring data press RUN STOP 3 47 Display Persistence 3 48 Reference CSA 803A User Manual Enhanced Accuracy The Enhanced Accuracy menu allows you to control the continuous self cali bration features of the CSA 803A It also allows you to perform some user assisted calibration procedures on the sampling heads You do not need tools to make these calibrations you use the front panel of the CSA 803A You can choose to have the CSA 803A calibrate the sampling heads auto maticaily or for most samplin
138. agation characteristics 2 78 Operating Basics Measuring Distance with TDR Example 10 Taking TOR Measurements One of the common uses of TDR is measuring distance The CSA 803A makes it easy to measure the length of a cable or circuit board run by using the Cursors major menu Distance is determined by the measuring the time required for a pulse to travel down a transmission line for example a cable or circuit board run and for its reflection to return The measured distance is dependent on the propagation velocity of the transmission line Step 9 Touch the Cursors icon to display the Cursors major menu C Step 10 Touch Cursor Type touch Vertical Bars in the pop up menu and then touch Exit O Step 11 Use the knobs to position Cursor 1 at the first rising edge and position Cursor 2 at the second rising edge You are now measuring the distance between the rising edge of the step leaving the head and the rising edge of the reflection If you select Feet for the Y Units in the Graticules pop up menu you can read the length of the cable in feet at the Af 2 readout The Af readout shows you the total dis tance traveled by the step and its reflection Divide that value in half Af 2 and you have the length of the cabie CSA 803A User Manual 2 93 Example 10 Taking TDR Measurements 2 94 Operating Basics CSA 803A User Manual Example 10 Taking TDR Measurements trig d ae SCRE ERR SUTURE R
139. age the mainframe the sampling head or both Channel Unit powered down during mainframe operation Cycle power to continue Do not change sampling heads with the power on Doing so may damage the mainframe the sampling head or both Channel Unit powered up during mainframe operation Cycle power to utilize Do not change sampling heads with the power on Doing so may damage the mainframe the sampling head or both Channel Unit was not maintained at desired calibration delay value Indicates that the automated calibration system attempted to adjust the delay of the named sampling head channel If you are not using the delay adjust feature of the Enhanced Accuracy major menu you can turn off the Delay Compensate selector to stop the CSA 803A from making the delay adjust calibration Connect a 50 0 terminator to the selected channel and press Proceed when ready The CSA 803A is waiting for you to put a terminator on the signal connector of the sampling head channel you are calibrating and touch the Proceed selector If you touch the Proceed selector without attaching the terminator the calibration will fail or the results will be inaccurate Delay adjust calibration failed can t find transition The required signal is not connected to the channel being calibrated Be certain to follow the instruction message on the display before touching the Proceed selector Delay adjust measurement on reference
140. ailable HPGL supports pen numbers 0 to 8 Screen Format The Screen Format selector provides several qualities of hard copy output Different format selections are available for different printer types a HiRes produces an enhanced contrast display on printers with limited gray scale capability Selected items including windows are highlighted for easy identification a Draft produces hardcopies faster than HiRes mode but sacrifices some gray scaie capability a Reduced produces low resolution hardcopies a quarter of the size of Draft hardcopies Advantages are quicker printing and use of less memory a Screen produces an exact color replica of the screen without reformait ing to enhance features Available for color printers and plotters only a Dithered reduces saturation and increases contrast by dithering icons and selector backgrounds May be used with Tek 4692 Tek 4696 Tek 4697 and Bitmap Dump Direction The Direction selector controls whether information is sent to a printer as horizontal rows or as vertical columns For most printers this has the effect of rotating the image by 90 Some printers will produce an image more quickly in one direction than in the other When Direction is set to Horizon tal screen information is sent to the printer by horizontal rows starting at the top left corner of the display When it is set to Vertical the information is sent by vertical columns starting at the bottom left corner
141. al Desc selector to see that M1 is the trace description If necessary touch the same area again to select the right trace L Step 12 Touch the vertical icon The knobs are set to Vertical Size and Offset of the channel indicated in the knob labels which is also the channel of the selected trace L Step 13 Turn the top knob right to set the vertical scale to 100 mV div Turn the bottom knob to the left to move a part of the trace off the grati cule The selected trace will change to be twice as high The difference trace will aiso change becoming quite ragged see Figure 2 23 This aberration is caused by a component signal being off the graticule The selected trace is off the botiom edge of the display and this means that the complex trace that depends on it is affected as well C Step 14 Turn the bottom knob to the right until the selected trace is completely on the graticule You will see the noise disappear from the difference trace O Step 15 Continue to move the trace up to the top half of the display and observe that as it moves the difference trace moves up as well NOTE Unless all component traces have the same vertical size a Fast complex trace will have undefined vertical units High Precision traces don t have this limitation C Step 16 Turn the top knob to the left to return the selected trace to its original size of 200 mV div CSA 803A User Manual 2 35 Example 3 Defining
142. aling When you define a new trace it is defined as either a fast trace or a high precision trace Fast traces are computed with integer arithmetic and oper ate significantly faster than high precision traces High precision traces use floating point arithmetic to provide highest precision Normally the trace is defined to be fast unless some part of the trace ex pression forces high precision Floating point functions such as Diff and Log will force the trace to be defined as high precision You can force complex traces to be defined as high precision traces by using the Instrument Options pop up menu in the Utility major menu in this pop up menu the Trace Scaling selector can be set to Optional or Forced When set io optional new traces are defined as fast traces if they can be implemented as fast traces When set to forced new complex traces are defined as high precision traces Single channel traces without wave form math are always acquired in Fast mode See Figure 3 103 Once a trace is defined its trace scaling cannot be changed The setting of the Trace Scaling selector affects only the definition of new traces Trace Scaling Sefector Tate 2i E ch Ontime LHS 7hrs Figure 3 103 The Instrument Options Pop up Menu 3 212 Reference Triggering A trigger is an electrical event that initiates acquisition of a trace The event that triggers acquisition is when the trigger source the signal bei
143. ameter On and then touching the r Run selector While the diagnostic tests are running the r Run selector changes to a q Quit selector You can touch this selector anyplace else on the screen ora button to stop execution of diagnostic tests When the extended diagnostic tests are complete the r Run selector is displayed again and the test status appears in the INDEX and FAULT columns When you are done with the extended diagnostic tests touch the e Exit selector twice in succession CSA 803A User Manual 3 39 Diagnostics 3 40 Reference Display Intensity To change the brightness of the display use the Instrument Options pop up menu from the Utility1 major menu Touch the Display Intensity selector in this pop up menu This assigns the knobs to control the intensity of the dispiay You can then use either knob to adjust the intensity See Fig ure 3 19 Display intensity can also be changed in the Color pop up menu or in the Persist Histograms pop up menu in the Display Modes major menu Gutaset Opti ans The Display intensity Selector Figure 3 19 The instrument Options Pop up Menu CSA 803A User Manuail 3 41 Display Intensity 3 42 Reference E Display Persistence Persistence is a measure of how long a data point remains displayed Traces can be displayed in four different persistence modes Normal Vari abie Infinite and Color Grading The persistence m
144. ampling heads A display should appear similar to the illustration in Figure 2 8 PATE a a ted Bill EEL apt heh Raney ware ANENoea Liccuracy lair JEE OPPE e E wate rtd oe Figure 2 8 The Calibrator Signal After Pressing AUTOSET in Edge Mode CSA 803A User Manual 2 11 Example 1 Displaying a Trace The Knobs 2 12 There are two control knobs to the right of the display and below the major menu buttons They adjust different things at different times You can always look at the Knob menu to see what the knobs will adjust This is called the current knob assignment The Knob menu appears on the display to the right of the major menu see Figure 2 9 The top two selectors of the Knob menu are haif height and always show the current knob assignment At present they show that the top knob controls the Main Size time per division parameter and the bottom knob Main Pos main time base position The bottom half of each selector shows the current vaiue of that parameter Figure 2 9 The Knobs and the Knob Menu Selectors may perform specific tasks or assign the knobs or do both Each knob assignment remains in effect until you change it with another selector or a major menu button Each major menu button remembers its current knob assignment meaning that if you change from one major menu to another and then return to the previous major menu the knob assignments will be the assignments that
145. an FFT Magnitude Dispiay The DC value displayed with the FFT magnitude is twice the actual DC amplitude This value does not include any vertical offset of the sampling heads When making measurements near DC use the rectanguiar window function Reference CSA 803A User Manual Fast Fourier Transforms Split dots cursors can be used to make phase measurements With both the magnitude and the phase of trace in the frequency domain displayed you can place one cursor on the FFT magnitude display and the other on the FFT phase display By adjusting the cursors horizontally so that the Af readout is 0 000 Hz you can easily match the phase readout to the corre sponding peak in frequency magnitude See Figure 3 32 fae Oe Cee pap i VEEN a PY H n EE NE ha i pi khoe div Figure 3 32 Using Split Dots Cursors to Measure FFT Phase 3 73 Fast Fourier Transforms FFT Windowing The Fast Fourier Transform operates on the time domain trace record ac Functions quired by the CSA 803A The FFT algorithm assumes that the signal is composed of an infinite repetition of this trace record Since the time domain trace record rarely matches an actual periodicity in the signal the frequency spectrum displayed will reflect extra frequencies due to discontinuities at the time domain trace record edges These addi tional frequencies are known as leakage error The effect of discontinuities at the ends of the time domain trace
146. an set the parameters for any trace to the complete set of defaults at any time You can access the default parameters through the Measurements pop up menu using the Default Parameters selector C Step 18 Touch the Measurements selector in the major menu and then touch the Default Parameters selector in the pop up menu The pop up menu changes to show measurement defaults see Figure 2 38 Touching the Measurement Functions selector redisplays the original Measurements pop up menu The new pop up menu shows the various parameters that the measure ments use No one measurement uses all of these parameters but each parameter is used for one or more measurements You can touch the various parameter selectors to assign the knobs to one or two of the parameters After setting the parameters as desired all traces created in the future will default to these measurement parameters NOTE Changing a default parameter does not affect any existing trace or measurement Operating Basics Example 5 Taking Automated Measurements Figure 2 38 The Default Parameters Pop Up Menu Step 19 Touch the Left Limit or Right Limit selector and turn the bottom knob counter clockwise to set the default right limit to 80 in addition all the parameters of the selected trace can be set to default values by using the Initialize Ali selector C Step 20 Touch the Initialize All selector and then the RMS selector on the major menu
147. and a red TDR ON indicator light canon Applying a voltage outside the range printed on the sampling head can result in damage Static electricity is a hazard The input diodes in sampling heads are susceptible to damage from electro static discharge and from voltage levels that are outside the range printed on the face of the sampling head Always wear an antistatic wrist strap connected to the ANTISTATIC CONNECTION on the CSA 803A when you are making connections to a sampling head or handling the device under test The channel indicator light can have three states off on steady or blinking The operation of the SELECT CHANNEL button depends on the light m ff the yellow light is off the channel is not displayed Pressing the button creates a trace of that channel m ifthe yellow light is on steady the channel is displayed but is not part of the selected trace Pressing the button selects that trace causing the light to blink m If the yellow light is blinking the channel is part of the selected trace Pressing the button will remove alf traces displaying that channel The red TDR ON light indicates whether or not the sampling head is send ing out a TDR Time Domain Reflectomeitry step through the signal connec tor You cannot control the TDR function from the sampling head front panel a menu in the mainframe is used to turn this feature on and off 3 171 Sampling Heads Controlling TDR and The time domain reflec
148. annel your trace is using and Smoothing Touch the Exit selector in the pop up menu NOTE if you turn on smoothing for one sampling head channel both channels are smoothed Observe the smoother trace o Step 19 Touch Sampling Head Fnce s in the major menu In the pop up menu touch 1 or whichever channel your trace is using and Smoothing to turn smoothing off Touch the Exit selector in the pop up menu see Figure 2 32 Note that neither smoothing nor averaging can be applied to random data displays such as eye patterns Figure 2 32 The Sampling Head Fne s Pop Up Menu 2 50 Operating Basics Example 4 Using Signal Processing Record Length You can specify the resolution of traces by setting the number of sample points in a trace This is most important if you are using a remote interface to transfer trace data to a computer but the effects are visible on the display The Horizontal Desc selector always shows the point count of the selected trace Step 20 Touch Horizontal Desc in the major menu In the pop up menu touch either Main Record Length or Window Record Length both selectors assign the knobs identically C Step 21 Turn the top Main Record Len knob one click at a time to the left and right and observe the difference in the main trace NOTE if the channel loop gain is not correctly calibrated changing record lengths can also change the trace appearance See Enhanced Accuracy in the
149. are Root Sgrt n W n where n index into record of data points Wn input sampled data point This function is implemented by the 80287 math coprocessor and support ing routines Smooth Centered Mode Non Causal Algorithm Smooth n ps Wim h n X mo maf forn lt h Smooth n wv _ mm men h forh snas R 1 hkh Smooth n a 3 Win M 1 n x WM v foran gt M 1 h D 10 Appendices CSA 803A User Manual Appendix D Algorithms where n index into record of data points W n input sampied data point s smoothing interval in samples the second argument h half interval s 1 2 rounded up R record length in points The centered mode smoothed trace is derived by computing the average value of the corresponding point of the original trace and some number of points of the original trace on either side of the corresponding point The number of points on either side is derived from the smoothing interval which is the second argument of the Smooth function Near the ends of the trace nonexistent points beyond the ends of the trace are required for averaging The nonexistent points are assumed to be the value of the corresponding end points This method of extending the trace is arbitrary so the results within a smoothing interval of the ends of the trace must be interpreted accordingly Shifted Mode Causal Algorithm n Smooth n 4 gt won
150. arithmic To change the histogram scaling touch Histogram Scaling Linear scaling better illustrates the relative quantity of various data while logarithmic scaling provides better detail at the edges of the histogram Histogram scaling is a display feature it does not affect the histogram data Clearing the Histogram Data To clear the data in the histogram display touch the Clear selector in the Persist Histogram pop up menu or touch the Clear Trace selector in the Remove Cir pop up menu Histograms cannot be displayed for stored traces Histograms can be displayed for calculated traces if the calculated trace contains at least one active channel even if the calculated trace contains a stored trace 3 105 Histograms The Histogram Readout 3 106 in the major menu area of the display is a readout of histogram characteris tics Included in the display are the values for the position of each of the sides of the histogram box statistical values and measurements See Fig ure 3 50 Figure 3 50 Histogram Readout Appears Below the Trace Display Top Btm Lft and Rgt represent the position of each of the sides of the histogram box in appropriate axis units That is Top and Btm values are given in volts Lft and Rgt are given in seconds a Mean is the average value of all the acquired points within the histogram box Pk Pk is the difference between the most positive acquired point and the least positive acquired
151. ase Main j mgie interual sie Interval ai Reference Point Me Acauired Trace XY Trace Section ee a ae ae a a ea ee ee ee ar ae Figure 3 112 The Horizontal Desc Pop up Menu You initiate and control XY traces using the Horizontal Desc pop up menu in the Waveform major menu See Figure 3 112 Two sections of the menu are titled XY Display Mode one for displayed traces and one for stored traces Use the following sequence to create XY traces C Step 1 Define a trace that shows the information you want on the X axis the horizontal axis This trace may be a displayed trace or a stored trace C Step 2 Define and display a trace with the information you want on the Y axis the vertical axis Step 3 Select the trace that displays the Y axis information C Step 4 Press the WAVEFORM major menu button and touch the Horizontal Desc selector to display the pop up menu 3 23 Reference CSA 803A User Manual XY Traces a Step 5 Touch the selector in the Horizontal Desc pop up menu that represents the trace showing the X axis information If the X axis trace is a displayed trace it will appear in the section titled XY Display Mode X Acquired Trace lf the X axis trace is a stored trace it will appear in the section titled XY Display Mode X Stored Trace When you touch the X axis trace selector in the Horizontal Desc pop up menu the trace is immediately converted into an XY trace
152. ata Interval is set to the entire zone Spectral Frequency See Frequency Domain Measurements on page D 16 See also Table D 2 on page D 16 Harmonic Mode 1 Scan measurement zone on FFT magnitude waveform to find the high est peak 2 Determine the largest adjacent spectral component 3 Using FFT window characteristics find the fundamental components S yand S 1 4 The nth frequency harmonic of the waveform is determined by multiply ing the harmonic number by fundamental frequency and then searching the waveform for the nearest spectral peak The interpolation algorithm is applied again in order to prevent the increase of the error rate by the harmonic number where SE J l is the ratio of the two highest peaks s __ icoeff 0 x a icoeff Z ig the interpolation value icoeff 2 Xo 1 where icoeff i is an array of interpolation coefficients which depend on the type of FFT windowing function refer to the table on the next page fundamental frequency A x fresolution where fresolution is the frequency resolution D 20 Appendices CSA 803A User Manual Appendix D Algorithms NOTE All even points of the frequency magnitude waveform are results of FFT calculation and all odd points are linearly interpolated points Thus the algorithm ignores all odd points The real frequency resolution is twice the frequency per point of the waveform Peak Search Mode 1 Scan the
153. ation is compiete When a message appears on the display you can remove it by performing any operation touching the graticule area making a menu selection or pressing a button When a hardcopy is made any message on the display is removed immedi ately before making the copy The meaning of most messages is self evident The listing below shows some of the messages that might be unclear and gives more information about the cause of the message Autoset failed bad trigger level Autoset failed due to a unacceptable trigger signal Autoset will not change trigger coupling slope or external attenuation Make certain these are appropriate for your trigger source before using autoset Baseline correction failed to find 1 p point lf the trace is not triggered or if the portion of the trace immediately to the left of the display earlier in time is not a flat trace the voltage reference cannot be determined Blowby calibration failed can t find reference step The required signal is not connected to the channel being calibrated Be certain to follow the instruction message on the display before touching the Proceed selector Appendix E Messages Calculated waveforms cannot be measured in hardware mode Hardware measurements can only be taken from traces without arithmetic operators or trace functions Change in channel Unit configuration Do not change sampling heads with the power on Doing so may dam
154. ation of mainframe and sampling heads has not changed since the last power off then the instrument will completely restore to the state it was in when powered off it takes about 20 minutes for the CSA 803A to warm up after power on You should perform any enhanced accuracy calibrations only when the instru ment has warmed up and achieved thermal stability The enhanced accu racy calibrations are described on page 3 49 3 167 Power On 3 162 Reference CSA 803A User Manual Record Length The number of samples that form a trace is called the record length You can select record lengths of 512 1024 2048 4096 and 5120 samples see Figure 3 74 For FFT traces the 5120 sample size is not selectable If the display mode is infinite variabie or color graded the 1024 2048 4096 and 5120 sample sizes are not selectable be cons figs div he 45ns Figure 3 74 Traces with Record Lengths of 512 top and 5120 bottom You can set the main record length and the window record length using the knobs All traces on the main time base have the same record length Win dow traces similarly share identical record length Variable Infinite and Color Grading persistence displays will work only with the 512 point record length If the record length is longer when one of these display modes is selected the record length is automatically shortened to 512 points Returning to Normal persistence does not reset the record length it
155. ayed sweep See Windows Delete Setting pop up menu 3 778 Delete Trace pop up menu 3 784 3 210 3 211 Diagnostics 3 35 3 40 extended 3 35 3 38 3 40 power on 3 35 3 36 self test 3 35 3 37 Diff TDR Preset Sampling Head Fne s 3 172 Differential TDR measurements 3 789 3 196 3 198 3 199 Display 1 71 1 30 Display intensity 3 23 3 47 Display modes 2 48 Display persistence 3 43 3 48 Displaying labels 3 778 Distal 3 757 E Electrostatic discharge C 3 Enhanced accuracy 3 49 3 60 automatic calibration 3 57 3 52 3 54 3 55 CSA 803A User Manual l 1 MOELE Index
156. b menu labels Turning the knobs shows that the vertical characteris tics of the trace are altered C Step 14 Touch the icon and turn each knob left and right Observe the changes in the trace 2 13 FFT Window Magnitude Define Trace Example 1 Displaying a Trace Cursors Horizontal i r r g 33 passe Re ye I rh ITI ptf Pet Ll ge re 5 e Vertical m T j p f ie f i i H fe j inya ipdn ugn ati E Figure 2 10 icons Operating Basics 2 14 Example 1 Displaying a Trace a The knobs can be adjusted to finer or coarser resolution with the Keypad Keypad Pop Up Menu and Knob pop up menu This menu also allows numeric entry of a parameter assigned f to a knob The Keypad pop up menu is displayed by touching either knob Resolution label selector in the Knob menu see Figure 2 11 Step 15 Touch the Vert Offset M1 knob label selector If you con nected your signal to a different channel you may see a different chan nel number The two selectors across the top of the Keypad pop up menu allow you to change the knob parameter The Knob Res section has selectors for Coarse Medium and Fine resolu tion Vertical offset does not support medium resolution so that selector is dimmed The other two selectors show the knob click increment coarse will set the knob to add or subtract 5 mV for each knob click while fine sets the knob increment to 500 pV The Coarse selector i
157. bits Touch the selector repeatedly until the appropriate number is shown in the selec tor You should set the number of stop bits to match the computer you are using Parity lets you select among Even parity Odd parity or None Touch the selector repeatedly until the appropriate setting is displayed in the selector Parity is an error detection scheme You should set parity to match that of the computer you are using a Flagging lets you select among Hard flagging Soft flagging or None Touch the selector repeatedly until the appropriate setting is displayed in the selector Flagging is used by the CSA 803A or the computer to signal that its input buffer is full and that the other device should stop transmitting until further notice When soft flagging is selected the CSA 803A sends a Ctrl S decimal 13 to signal the other device to stop transmission and recognizes Ctrl S as a signal to stop transmitting Ctrl Q restarts transmission When hard flagging is selected the CSA 803A uses the RS 232 C DSR DTR signal to control data transmission You should set the type of flagging to match the computer you are using a Delay assigns the knobs to baud rate and delay Delay is the mini mum time that the CSA 803A will wait before responding to a command sent from the computer The delay setting can be 0 to 60 seconds w EOL String lets you select the end of line query terminator to one of the following LF Line Feed CR
158. ble connectors on the CSA 803A m Standard SMA connectors with plastic insulating material between the center lead and the outer shield An example is the INTERNAL CLOCK output connector on the front panel m High precision APC 3 5 connectors which have air insulation between the center lead and outer shield Examples include the input connectors on some of the sampling heads The APC 3 5 connectors are of closer mechanical tolerance than the stan dard SMA connector Attaching a worn or damaged SMA cabie to an APC 3 5 connector may damage the APC 3 5 connector Higher bandwidth sampling heads may use other connectors that are not SMA compatible Consult your sampling head manual for more information Electrostatic Discharge i canon Applying a voltage outside the range printed on the sampling head can result in damage Static electricity is also a hazard The input diodes used in the sampling heads are very susceptible to dam age from overdrive signal or DC voltages and from electrostatic discharge Never apply a voltage outside the range printed on the front of the sampling head Operate the CSA 803A only in a static controiled environment CSA 803A User Manual 7 5 Introduction Connect the wrist strap provided with the CSA 803A to the ANTISTATIC CONNECTION as shown in Figure 1 1 Front Panel Never install or remove a sampling head with the CSA 803A power on The front panel has two compartments for sampling h
159. box the color of that display elernent and beneath the selector is a readout of the hue lightness and saturation values of that color m Hue is the characteristic associated with a color name such as red It is expressed in degrees on a range of 0 to 360 a Lighiness is the intensity of the color or the amount of light it transmits Lightness is expressed from 0 black to 100 white Saturation is the vividness of the color or the extent that it differs from gray Saturation is expressed from 0 maximum white content to 100 fully saturated To change the color of a display element select the element in the Color pop up menu The knobs are automatically assigned to control Lightness and Saturation select Hue if you want to adjust the hue of the color Adjust the color using the control knobs 3 21 Color Display Figure 3 10 The Color Pop up Menu Restoring Colors Two selectors in the Color pop up menu let you restore colors to their default settings or to the colors previously defined Previous Colors restores all eight display elements to the colors they had when you displayed the Color pop up menu Default Color sets the selected display element to the factory default color When no dispiay elements are selected the All label is displayed below the Default Color selector and touching Default Color sets all eight dispiay elements to the factory default colors 3 22 Reference Rea
160. c protection wrist strap C Step 1 Initialize the CSA 803A press the UTILITY button in the MENUS column touch Initialize in the major menu and touch Initialize in the verification pop up menu C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A C Step 3 Attach the power divider to the CALIBRATOR output connector of the CSA 803A C Step 4 Connect cables from each branch of the power divider to sam pling head input connectors khe Power Divider Short Cable Long Cable Figure 2 21 Connections for Example 3 Step 5 Press the TRIGGER button in the MENUS column and touch Source in the major menu and Internal Clock in the pop up menu Touch Exit to remove the menu C Step 6 Press the SELECT CHANNEL button on each channel that you have connected the calibrator signal to CSA 803A User Manual 2 31 Example 3 Defining Complex Traces C Step 7 Turn the top knob to the left until the horizontal scale is 5 ns div Don t use the AUTOSET button You should see the calibrator trace on the display twice Because of the different lengths of the cables you are using the edges of these traces will be separated by 3 ns Turning on vectored traces will make the edges more visible C Step 8 Press the UTILITY button and select Instrument Options in the Utility major menu Select Vectored Trace in the pop up menu and touch Ex
161. cause you can select a particular standard mask and the instrument will immediately per form standard mask autoset and begin mask testing You can change the signal source press AUTOSET at the front panel and the instrument will perform standard mask autoset and begin mask testing on the new signal source See Mask Testing page 3 119 in this manual for more information When performing a standard mask autoset for pulse masks not eye pattern masks the instrument turns on waveform averaging and acquires the number of waveforms indicated or selected in the Acquire Description pop up menu before performing autoset In this way the autoset is more accurately performed to an average For this autoset you can set the num ber waveforms averaged to between 8 and 128 You can select greater or fewer waveforms for the average however the instrument limits the selection to this range for this autoset You can use this feature to control the speed and accuracy of autoset for pulse masks Many of the standards specify voltage levels for the signal For these stan dards be sure to enter any external attenuation that may be in the signal You can do this from the Sampling Head Fnes pop up menu in the Wave form major menu For bipolar signals you may want to compare the negative pulse to the standard mask To do this define the trace as M not 1 x M1 You can use the Vertical Description pop up menu Standard mask autoset will work for in
162. ce An outline box indicates your potential selection If only one trace passes through that outlined area when you withdraw your finger it will become the selected trace If several traces pass through the outlined area repeatedly touching the same area will select successive traces _ Step 14 Touch the traces to change selections Try touching an area with one trace and an area where both appear together The Waveform major menu shows status of the selected trace see Figure 2 16 The Vertical Desc selector shows the trace expression of the selected trace a Step 15 Press the WAVEFORM major menu button in the MENUS column and observe don t touch the Vertical Desc selector If the selected trace displays mainframe channel 1 then the Vertical Desc selector will show M1 Fast is a trace parameter that is described in Example 3 Channels can be combined in a single trace for example M1 Ms3 as you will see in Example 3 The Remove Cir Trace n selector of the Knob menu also shows the expres sion of the selected trace It also indicates that the Main time base is used Figure 2 16 The Waveform Major Menu with the Knob Menu The number n in the Remove Cir Trace n selector is the trace number assigned by the CSA 803A when the trace is created It should not be confused with the trace expression Trace numbers range from 1 through 8 This selector always shows the number of the selected trace L Step 16 Select e
163. ch the horizontal icon gt and turn the bottom Window Pos knob left and right The highlighted portion of the main trace moves and the window trace tracks it Step 25 Turn the top Window Size knob left and right one click at a time The size of the highlighted area changes and the window trace reflects that change You can add another window trace that is based on the original main trace but you cannot take a window of a window Since the window trace is the selected one there is no Window icon above the lower graticule _ Step 26 Touch the main trace to select it and then touch the Window icon on that graticule A second window trace is created and shares the lower graticule with the original window trace Two highlighted segments appear on the main trace This new window is on its own window time base C Step 27 Turn the bottom Window Pos knob The second window trace moves Step 28 Turn the top Window Size knob This knob changes the size of both windows The two window traces are placed on top of each other You can separate them vertically Normally the Chan Sel selector of the Knob menu see Figure 2 26 on successive touching shows ail the channels that are repre sented in the trace For window traces this selector also includes a Trace Sep setting which causes the knobs to move the selected window trace vertically This moves only the selected trace Chan Sel Selector Figure 2 26 The Chan S
164. channel failed Can t find transition The required signal is not connected to the channel being calibrated Be certain to follow the instruction message on the display before touching the Proceed selector E 2 Appendices CSA 803A User Manual Appendix E Messages Error detected in acquisition system channel The time base controller detected an acquisition system error You should contact your service person The message is accompanied by six groups of four characters You should note the accompanying information for your service person Front panel locked out A command from a computer on a remote interface GPIB or RS 232 C has disabled the touch panel Touches are ignored until the remote computer restores touch panei operation Hardcopy absent or off line Either no printer is connected to the CSA 803A or the printer that is con nected is not on line Until the condition is remedied hardcopies cannot be taken Minor time base calibration problem channel The time base calibration is no longer accurate to enhanced accuracy specifications Be sure you wait 20 minutes for the CSA 803A system to warm up before performing enhanced accuracy calibrations If this error message occurs repeatedly after warm up contact your service person Non volatile RAM completely reset probable battery failure Due to a battery failure all instrument data in non volatile RAM was lost at power on Lost data incl
165. con When you display the Vertical Desc pop up menu the trace expression of the selected trace appears at the top of the pop up menu You can use the Back Space selector to alter the trace or you can extend the trace expression When you touch the Enter Desc selector the new trace expression is applied to the selected trace CSA 803A User Manual 3 209 Trace Definition and Management Removing Traces You can remove traces from the display in three different ways using the Remove selector in the Remove Cir pop up menu using the Select Chan nel button on the sampling head or using the Delete Trace selector in the Store Recall menu Removing Traces Using the Remove Selector The Remove selector in the Remove Cir pop up menu always shows the number the trace expression and the time base of the selected trace The Remove Cir selector menu is displayed at all times and so the Remove selector is available regardless of which major menu is displayed As shown in Figure 3 102 when you touch the Remove Cir selector a smali pop up menu appears allowing you to remove or clear the selected trace Removing a trace turns off the selected channel and causes the trace to disappear Ciearing a trace affects averaged enveloped color graded variable persistence and infinite persistence waveforms Touching Clear causes the selected function to start over removing all current waveform data The selected waveform remains on screen its descripti
166. ctive ground all parts of the CSA 803A are shock hazards This includes knobs and controls that may appear to be insulators Use the Proper Fuse Using an improper fuse can create a fire hazard Always use fuses that exactly meet the specifications in the CSA 803A parts list Match fuse type voltage rating and current rating Do Not Operate in Explosive Atmospheres The CSA 803A provides no explosion protection from static discharges or arcing components Do not operate the CSA 803A in an atmosphere of explosive gases Do Not Remove Covers or Panels To avoid personal injury do not operate the CSA 803A without the panels or covers Operating the CSA 803A without the covers in place may cause overheating and damage Getting Started introduction Electrical Connections SMA Compatible and Other Precision Connectors You must attach cables to SMA compatible and other precision connectors carefully to prevent damage to the cable or the instrument connector Do not over tighten SMA compatible connectors When attaching a cable to or removing a cable from an SMA compatible connector do not turn the cable turn only the nut Align the two connectors carefully and engage the connector nut over the exposed threads on the other connector Use only finger pressure to make this initial connection Then use a torque wrench only to tighten the connection to the range of 7 10 Ib in 79 112 N cr There are two types of SMA compati
167. d leaving a single graticule 3 86 Reference Changing Axis Units CSA 803A User Manual Graticules Usually the graticule axis labels are units of time on the horizontal axis and units of voltage on the vertical axis For some tasks these axis labels are more meaningful if expressed in other units Horizontal units of distance are appropriate for TDR and TDT measurements The CSA 803A allows you to specify the horizontal axis units to be feet meters or inches You can also specify the propagation delay which is the fraction of the speed of light at which signals travel through your transmission line The vertical axis units most appropriate to TDR measurements are either units of rho p or of impedance Z The CSA 803A lets you specify units of rho for the vertical axis Rho values can be converted to impedance values by using the following equation where Zo is usually 50 Q 1 p Z Zo i NOTE Changing axis units on one graticule also changes the axis units of all graticules displayed However readout of impedance is available from the Cursors menu whenev er the vertical axis is scaled in rho units The status area of the Graticules selector in the Waveform major menu always shows the number of graticules and the axis units of measure Rho is not selectable for vertical axis units unless the selected trace is dis played in Volts units and TDR is turned on Vertical Axis Units To change the vertical axis units u
168. d the Graticules selector is renamed Upper Graticule or Lower Graticule depending on which graticule has the icons and the selected trace Reference Graticules ae ES i Sraticules yo Units x tsesaren anses mt Figure 3 43 The Graticules Pop up Menu CSA 803A User Manual 3 85 Graticules M anaging Graticules When only one graticule is being displayed you can create a dual graticule and Traces display using the Graticules pop up menu from the Waveform major menu Touch the Create Second Graticule selector in this pop up menu The selected trace and all traces from window time bases will be placed on the lower graticule The upper graticule will show all other traces When two graticules are being displayed you can move the selected trace from the graticule it is on to the other Touch the Move Trace to Other Graticule selector to move the trace After the trace is moved it remains the selected trace The horizontal icon lt gt and vertical icon move to the new graticule When two graticules are being displayed you can combine the traces from both graticules into a single graticule display Touch the Reduce to One Graticule selector to combine the traces onto one large graticule The trace that was selected before the operation remains the selected trace on the new single graticule When the last trace is removed from the second graticule the second graticule is automatically remove
169. d between time intervals is necessary to determine the crossing times when the proximal and distal values do not correspond to acquired data Frequency 1 Search the measurement zone for the left most mesial crossing of positive slope Continue the search to the right to find the first upper signal noise ratio level crossing to the right of the first mesial crossing The horizontal coordinate of this crossing is Cross 2 Search the measurement zone for the left most mesial crossing of negative slope Continue the search to the right to find the first lower signal noise ration level crossing to the right of the second mesial cross ing The horizontal coordinate of this crossing is Cross 3 If Cross lt Cross set Cross Cross Cross Cross and Slope positive lf Cross gt Cross set Cross Cross Cross Cross and Slope negative 4 lf Slope positive search for the third left most mesial crossing and continue the search to find the next upper signal noise ratio level cross ing to the right If Slope negative use the next lower signal noise ratio level crossing to the right The horizontal coordinate of this crossing is Cross 5 Calculate the frequency i Frequency cai Cross Cross Linear interpolation between vertical points and between time intervals is necessary to determine the crossing time when the mesial value does not correspond to acquired data CSA 803A User Manual
170. d in the background as long as the Display Modes major menu is displayed even if you select the Persist Histograms pop up menu If you select another major menu the mask is removed and counting is cancelled However the last displayed masks is redisplayed if you again select the Display major menu Masks are global That is all traces share the same masks However only data from the selected trace is counted when mask testing is on even if other traces fall within the mask boundaries As described earlier mask testing in Color Grading mode is an exception samples from all traces are counted in Color Grading mode When you select another trace all mask counts are cleared Clearing the Hit Count To clear the counters in the mask readout display the Mask Testing menu and select Clear Hits This sets the counters for the various masks the total hits and waveform counters to zero in addition to clearing the waveform data for the selected trace Like histograms these counters are cleared by any implicit or explicit clearing of the waveform data such as selecting Clear Trace from the Remove Cir pop up menu Limiting Acquisition You can limit acquisition under mask testing based on either the number of waveforms acquired or the number of mask hits detected These functions are controlled by the Set N and Stop N selectors in the Mask Testing pop up menu To limit acquisition based on the number of waveforms acquired display the Mask T
171. d prices see a Tektronix products catalog or contact your local Tektronix field representa tive u Option 1R Rack Mount converts the CSA 803A for rack mounting x Option 1T provides 38 predefined telecommunication masks conforming to ANSI SONET CCITT Optical Standards CCITT G 703 Electrical Stan dards and ANSI 11 102 Electrical Standards x Option 10 Delete Prescaler deletes the Prescaler trigger input u GPIB cable two meter Tektronix part number 012 0991 00 m RS 232 C cable ten foot Tektronix part number 012 091 1 00 s Ten foot Centronics printer cable Tektronix part number 012 0555 00 Sampling head extender cable one meter Tektronix part number 012 1220 00 CSA 803A User Manual A 1 Appendix A Accessories Power Cord Options A 2 Sampling head extender cable two meter Tektronix part number 012 1221 00 Sampling head panei blank Tektronix part number 200 3395 00 Acquisition extender Tektronix part number 067 1323 00 Acquisition System extender Tektronix part number 067 1324 00 Calibration pulser Tektronix part number 067 1338 00 Hardcopy unit Epson compatible Dot Matrix Printer Tektronix 4697 Tektronix SCOPE MOBILE cart Model 205 Calibration Head Tektronix part number 067 1413 00 The following power cords are available for the CSA 803A Option A1 Universal European 220 V 6A 50 Hz Tektronix part number 161 0066 09 Option A2
172. des components at frequencies higher than the Nyquist frequency These frequency components appear in the FFT trace display as peaks at lower frequencies The higher frequency components are reflected around the Nyquist frequency For example a frequency component 5 MHz above the Nyquist frequency will appear as a peak 5 MHz below the Nyquist frequency in the FFT trace display You can eliminate aliasing by setting the effective sample rate to be at least twice the highest frequency in the input signal Increasing the record length or decreasing the horizontal size will increase the effective sample rate The best way to avoid aliasing is to either apply an external filter to the signal to cut out high frequency components or use the filter function with a speci fied risetime limit For example to create a filter to reduce aliasing touch the following selectors defTra FFTmag Filter M1 1 EEX 9 This filter will limit signal risetime to 1 ns or limit bandwidth to 350 MHz You can apply averaging to the source trace to reduce random noise and prevent aliasing of high frequency noise in repetitive traces Define your trace as an averaged trace before selecting the FF Tmag icon or make averaging part of the trace description when you define the FFT trace in the DefTra pop up menu for example FFTmag Avg M1 You can also average the FFT trace for example Avg FFTmaq M1 Another way to decrease aliasing is to
173. dge of signal across 20 or less of the display or Period mode which shows three or more complete cycles of a signal Note that for Standard Mask Autoset the Autoset Mode does not apply See Standard Mask Autoset on page 3 11 Standard Mask Autoset The CSA 803A can be configured to perform an autoset automatically when ever a standard mask is selected from the Standard Mask pop up menu which is available in the Display Modes major menu A standard mask autoset sets the horizontal vertical and trigger parameters to the signal characteristics of the selected standard mask By setting Stan Mask Auto set to Auto the instrument performs the autoset when a standard mask is selected If Stan Mask Autoset is set to Manual the standard mask auto set occurs only when you press AUTOSET at the front panel Note that after initialization the instrument defaults to Manual You can turn off the trigger parameter adjustments during standard mask autoset from the Instrument Options pop up menu Setting Trigger Autoset to Off causes the CSA 803A to leave trigger parameters unchanged during a standard mask autoset Also when Stan Mask Autoset is set to Auto then whenever you perform a standard mask autoset either by first selecting the standard mask or by pressing the AUTOSET button the instrument immediately begins counting mask hits and also enables Stop N Waveforms on the Mask Testing pop up menu This feature helps simplify your testing sequence be
174. dou Made i rac i Status Window Figure 3 110 The Window Mode Pop up Menu The electrical event that triggers the automatic window position is the point at which the main trace passes through a specified voltage level in the specified direction the slope the specified number of times the transition number You can specify the voltage level in volts absolute or as a percentage of the baseline to topline voltage of the trace relative 3 225 Windows The selectors of the Window Mode pop up menu let you contro the window positioning in the following ways e Position Mode can be set to Manual you position the window with the knobs or Automatic the CSA 803A positions the window based on an electrical event on the main trace Automatic window positioning has a resolution equal to one Main record sample interval If the Main record sampie interval is large compared to the window size the position may appear to jump In most cases this will not affect the accuracy of measurements because the CSA 803A automatically compensates for the change in position Transition Number assigns a knob to specify the number of times the electrical event must occur before the window trace is positioned This affects only an automatic window with tracking on or an automatic window when locate window is performed w Slope selects between a rising siope transition event or a failing slope transition even
175. e Use the automated measurement system whenever you can both for convenience and for accuracy Use dot cursors to take a more precise measurement when record length is greater than 512 points Bar cursors are best for visual com parison and are positioned with display resolution when record length is 512 points Dot cursors follow the trace vertically as you position them horizontally and provide readouts of actual trace data values Aiways use the fine knob resolution to perform the final cursor position ing Setting one cursor knob to fine will also set the other When using cursors or software measurements always make the area to be measured as large as possible and cover as much of the graticule area as you can This will give the finest resolution 2 73 Example 6 Taking Delay Measurements Using Cursors AEAEE AAA E a AA aani R HH SSS AAAA HHO 2 74 Operating Basics CSA 803A User Manual Example 7 Taking Comparison Measurements Using a Reference Trace This example demonstrates the compare and reference features of the automated measurement system This is particularly useful when you need to check a series of components or circuits to see if a particular measure ment falls within an acceptable range For this example you will need a CSA 803A with at least one sampling head installed two SMA cabies of different length 2 ns and 5 ns cables are recommended and a static protection wrist strap C Ste
176. e 5 F Finar ne Figure 3 29 Equations for Frequency Interval and Frequency Range 3 68 Reference Changing Horizontal and Vertical Size CSA 803A User Manual Fast Fourier Transforms You can change the horizontal and vertical size and position of the FFT trace display by selecting the vertical and horizontal icons and using the knobs to adjust size and position When you touch the horizontal icon lt gt the knobs are assigned to control Frequency Span div and Frequency Resolution The Span div function changes the Main Size time base setting or for windows the Window Size setting The resolution function changes the record length When you adjust Frequency Span div and Frequency Resolution you are changing the time base of the source trace so you will see a change in the display of all traces on that time base You can also use Pan Zoom to horizontally expand the display of the FFT trace without affecting the time base Changing the horizontal magnification and position of an FFT trace using Pan Zoom changes the appearance of the trace but does not increase the horizontal frequency resolution For more details about Pan Zoom including changing the pivot point and using multitrace Pan Zoom see page 3 109 You can also change the frequency interval and frequency range by chang ing the record length and horizontal size of the time domain trace If the record length increases frequency resolution improves O
177. e ments they are removed from the trace measurements and a message appears on the display to warn you that some measurements have been removed Any timing measurements that were established are kept and changed to hardware mode measurements When you select Software Mode all existing timing measurements are kept and converted to software measurements If the Jitter or Noise measure ments were established in statistics mode they will be removed when you switch to software mode When you select Statistics Mode all existing measurements except for the Frequency Domain measurements are converted to statistical measure ments You must be in the color graded display mode in order to use statis tics mode Frequency domain measurements FreqDomain are only available if the selected waveform is an FFT magnitude waveform and you select the Soft ware Mode Reference Comparing Measurements to References CSA 803A User Manual Measurements You can establish reference vaiues for your measurements and have the CSA 803A display the measurement readouts as the amount of variance from the reference value For example you can store the propagation delay through the cables that connect to your device under test Then by turning on compare mode you can measure the delay through the device under test with the cable delay automatically removed from the measurement result You can also use this feature to compare measurements on several diff
178. e page 3 179 Use the ON STANDBY switch as the power switch once the instrument is instalied See page 3 159 These sampling head compartments are power only They are for use with sampling heads like the SD 51 SD 42 and SD 46 See page 3 169 You install sampling heads in the sampling head compartmenis See page 3 169 The CALIBRATOR output provides a known signal for calibration See page 3 19 The INTERNAL CLOCK OUTPUT is a trigger signal synchronized with the CALIBRATOR internal Clock Output There are two trigger inputs DIRECT See page 3 19 and PRESCALE DIRECT is DC coupled with a bandwidth of 3 0 GHz PRESCALE is an AC coupled digital prescaler which extends the trigger bandwidth to 10 GHz See page 3 214 CSA 803A User Manual At a Glance Rear Panel Power line controls include the LINE VOLTAGE The RS 232 C connector allows a SELECTOR SWITCH the remote computer to control the fuse the power connector instrument through a serial interface and the PRINCIPAL POWER it can also be used to drive serial SWITCH See page 3 159 output devices See page 3 165 The PRINTER connector lets you attach several kinds of printers using a Centronics interface See page 3 89 The GPIB connector allows a remote computer to control the SS instrument through an IEEE Std 488 z paraliel interface it can also be o used to drive compatible plotters Three lights show the status of the parallel
179. e 3 208 selecting Traces by OUCH 2a sd4s shes ee ie aiee Geeet eee an 3 208 Selecting Traces Using the Trace Status Menu 3 208 Selecting Traces Using the Sampling Head Channel BON siones reenn aara bent nad r E aD E OA 3 209 Modifying Traces x5 cuctsen cviedeteus ee ses os oe eee ener 3 209 CSA 803A User Manual ix Table of Contents REMOVING Traces ic ose econ veo ox od Rae KAW eR Vee eae ON 3 210 Removing Traces Using the Remove Selector 3 210 Removing Traces Using the Sampling Head Channel BUTON gN Ue ne tert eet ee Ne elit ihe wage eas Suey 5 3 210 Removing Traces Using the Store Recail Delete Trace Selector pete ei eee eke eed cane te a a i 3 210 Trace Scalig 255255 Fseetewsie nw ehwe eee dese tie te eeew tiers 3 212 TIQQGHNG adie unevosicere enki a EEE eeeteee t 3 213 Vectored ThACOS 6ni 55 ess 5805 anean PRE 6a TEN oe hoes we 3 217 Vertical Controls lt 2 csievaccia tua sece ee Sees daweseeeees 3 219 Setting Vertical Size and Offset 0 eee c ween an ceeee 3 220 Adjusting Channels and Adjusting Traces 3 220 Adjusting High Precision Traces cae eeeee 3 220 Trace Separation 5 1 5 i1ceia nae edd ange he eee ate Maemeere lt 3 221 WINGOWS eaaa een En OE Shea eee toad cep eae eee 3 223 Changing Window Size and Position 0 0eeeeees 3 224 Trace Separation 55 aih Sine Se eon ee ees oe RN 3 224 Positioning Window Traces Automatically 3 22
180. e only When measuring jitter for a trace that is an eye pattern set the Eye Pattern selector in the Measurements pop up menu to On This ensures a more accurate measurement Area and Energy Measurements Area The area under the curve of a trace Area The difference between the area under the curve above a reference level and the area under the curve below that reference level Energy The energy represented under the curve of a trace This integral of the squared voltages can be divided by the resistance of the circuit to yield power measurements Frequency Domain Measurements Spectral This provides frequency tracking for the fundamental Frequency and user specific harmonic as well as spectral peak frequency measurements Spectral This provides amplitude tracking for the fundamental Magnitude and user specific harmonic as weil as spectral peak amplitude measurements THD Total harmonic distortion 3 139 Measurements Setting Up a are rap o SEN rpa a on oo urements are based must be adjusted so that all areas that are needed to Measurements take the measurements are visible on the display No part of the trace should extend above or below the graticule display area If a measurement requires a full cycle as in frequency or period measurements then adjust the horizontal size to show at least one complete cycle of the signal Ifa measurement requires a rising or falling edge as in rise or cross measure men
181. e pop up menu Select Edge mode if it is not already selected Touch Exit to remove the pop up menu O Step 23 Press AUTOSET You shouid now see the rising edge of the calibrator signal 2 64 Operating Basics Example 5 Taking Automated Measurements C Step 24 Press the DISPLAY MODES button Touch the Persist Histo grams selector in the major menu then touch the Color Grading selec tor in the pop up menu Touch Exit to remove the menu Step 25 Press the MEASURE bution Touch the Measurements selec tor To enable statistics mode measurements touch Statistics Mode at the top of the pop up menu Touch Jitter and then touch Exit to remove the menu The data used for the statistics mode measurements are taken from the statistical database created when Color Grading is enabled This capability enables you to make automatic pulse parametric measurements directly on random data such as eye diagrams See Figure 2 40 Figure 2 40 A Jitter Measurement on the Calibrator Signal CSA 803A User Manual 2 65 Example 5 Taking Automated Measurements 2 66 Operating Basics Example 6 Taking Delay Measurements Using Cursors This example shows another way to measure trace parameters using cursors When the measurement you want to make is not included in the list of automated measurements you can use cursors You will use the cursors to take two common measurements trace ampli tude and delay between traces The CSA
182. e record However the oscilloscope remembers any forced horizontal position changes and re stores the position to its original location when the main size is set to smaller values if the user adjusts the main position when the setting has been forced to change the CSA 803A does not restore the old position when main size is decreased 3 111 Horizontal Controls OEE a paint It bent ot ke ow ek iG i 3 Ca i i i i i i i i i i i a Reference c ies i l H H 1 i i j 7 a2 a Sern ct ee mae A HOguUired irate i i 3 H i i i gt i i j H H i j i i H H j Figure 3 53 The Horizontal Desc Pop up Menu 3 112 Reference Initialization Whenever you begin a new task using the CSA 803A you shouid initialize the system so that all settings are at factory default That way you do not get unexpected results because of settings remaining from the last use of the CSA 803A To initialize the system settings to default touch the Initialize selector in the Utility1 major menu then touch Initialize in the Verify initialize pop up menu as shown in Figure 3 54 Figure 3 54 The Initialize Verification Pop up Menu An alternate method to initialize is to select Initialize Setting in the Recall Setting pop up menu in the Store Recall major menu The f
183. e traces one trace is brighter because it is the trace for which the axis labels are correct The axis labels are displayed in the same color as this trace The other traces may or may not share the same axis labels NOTE Traces extend outside the graticule area slightly The axis labels represent the graticule edge not the trace edge CSA 803A User Manual 3 83 Graticules 3 84 You can display two different graticules each being half the height of a single graticule display In this case each graticule shows one trace brighter than any others on that graticule In addition the graticule with the selected trace has the vertical and horizontal lt gt icons The bright trace on the graticule with icons is the selected trace See Figure 3 42 The menu selectors act on and report the status of the selected trace icons Selected Trace oo ee Figure 3 42 Dual Graticules with Multiple Traces You can make any trace the selected trace by touching it If you select the wrong one because the traces are close together touch again until the desired trace is selected and becomes brightened Other methods of select ing traces are discussed in Trace Definition and Management on page 3 203 You can control the number of graticules the placement of traces on the graticules and the graticule axis units by using the Graticuies pop up menu in the Waveform major menu See Figure 3 43 When dual graticules are displaye
184. e x at each of its vertices To add a point to the Mask1 component use the knobs to locate the cross hair cursor over the location where you want to add a point Touch Add Point To delete a point from a mask locate the cursor over the point to be deleted Touch Delete Point When you are finished editing Mask1 and want to edit Mask2 touch Mask Testing again Now touch Maskz2 to select it for editing Then touch Edit Mask Defn Now Mask2 is highlighted with a blue x at each of it vertices You can now edit Mask2 as you did Mask1 and so on for the Mask3 and Mask4 components if present When you are finished creating the new user mask touch Exit Mask Edit ing Note that modifying a standard mask creates a user mask and has no affect on the standard mask Also Standard Mask Autoset is not available on a user mask even though the user mask may have been created from a standard mask The only exception is the user eye mask Creating a User Eye Mask The Create User Eye selector in the Mask Testing pop up menu lets you create one custom eye mask per setting from an existing standard eye mask This User Eye Mask is similar to standard eye masks because the instrument can perform Standard Mask Autoset for user eye masks that you create To create a custom user eye mask first acquire a trace and then select the Standard Masks pop up menu The default user eye mask is a 9 9533 Gb mask that is similar in appearance to the OC48 STM16 mask ava
185. eads At least one sampling head must be installed in a CSA 803A configuration to allow the CSA 803A to sample signais Two additional compartments labeled AUXILIARY POWER ONLY provide power for non acquisition heads such as a trigger countdown or optical electrical converter These compartments cannot be used to acquire signals The TRIGGER INPUTS the INTERNAL CLOCK output and the CALIBRA TOR output connector are located below the sampling heads The tutorial procedures in this manual describe the use of these connectors See Fig ure 1 1 Power only Sampling Head Compartments Compariments Clere External Trigger Inputs Antistatic internal Clock Calibrator Connection Output Output Figure 1 1 Front Panel Connectors 1 6 Getting Started CSA 803A User Manual Introduction Rear Panel The POWER plug provides AC power to the CSA 803A The piug is an IEC style connector the separate power cord supplied with the CSA 803A should match the physical configuration of electrical outlets in your country Set the LINE VOLTAGE SELECTOR switch before connecting the CSA 803A to power Before connecting the power cord between your electrical outlet and the CSA 803A POWER plug make sure that the adjacent LINE VOLTAGE SELECTOR switch is set to match the voltage range of the electrical system of your couniry The main fuse is near these controls as is the PRINCIPAL POWER SWITCH See Figure 1 2 Principal Line Volta
186. easurements Pop up Menu with Frequency and RMS Selected When the measurements you want are selected you can remove the pop up menu by touching either the Exit selector in the pop up menu or the Measurements selector in the major menu area This lets you see the trace as the measurements are taken NOTE if your Measurements pop up menu shows only timing measure ments touch the Software Mode selector at the top of the menu Measurements are part of the definition of a trace When the Measure major menu is displayed the measurements of the selected trace are also dis played CSA 803A User Manual 3 141 Measuremenis Deleting Measurements Topline Baseline Calculation 3 142 To delete a measurement that is established on a trace touch the Measure ments selector in the Measure major menu In the pop up menu touch the selectors for the measurements you want to remove As you touch the measurement selectors they will turn off highlighting and the measurement readouts will be removed from the major menu area Clear All deletes all measuremenis When you are finished removing measurements touch the Exit selector to remove the pop up menu The Top Base Method selector allows you to select the method of determin ing the topline and baseline You can choose between the standard IEEE method histograms or an alternate method that smooths and differentiates the waveform data before calculating topline and baseline The alter
187. ecall User Const selector of the Calibrate All pop up menu will recall and use ail the calibration values for the selected sampling head channel You can also recall the calibration values that were set at the factory by touching the Recall Defaults selector of the Calibrate All pop up menu Since temperature and humidity variations affect calibration these factory defaults may only approximate ideal performance of your sampling heads Reference Sampling Head Calibrations CSA 803A User Manual Enhanced Accuracy You can perform individual calibrations on the sampling heads If you have used the Calibrate All pop up menu to calibrate the sampling head chan nel you have already performed alf the calibrations and there is no need to repeat them individually Note that for a dual channel sampling head cali brating one channel on a sampling head head does not affect the other channel you need to calibrate both channels separately You should refer to the User Installation Manual for the sampling head or heads that you are using This will teil you which calibrations are appropriate to that particular head Some sampling heads do not require or allow certain calibrations Some calibrations are rarely needed on certain types of sam pling heads You can make five individual calibrations on the sampling heads w Blowby Compensate adjusts the sampling head to minimize DC level trace aberrations near the point of a large voltage change
188. ect Split Dots the pop up menu stays on the display and the lower half of the pop up menu is active The lower menu shows a selector for each displayed trace for exampie Trace 1 Trace 2 The selector for the displayed trace is highlighted At this point both split dot cursors are assigned to the selected highlighted trace To assign the second right most cursor to a different trace touch the selector for that trace This action removes the pop up menu and moves the second cursor to the selected trace Cursor Calibration Cursor readout can be referenced to a user set horizontal point This is useful for making distance or time measurements using TDR or TDT To specify cursor readout based on cursor position press the Set Zero selec tor The Set Zero pop up menu is displayed See Figure 3 15 Figure 3 15 The Set Zero Pop up Menu To set the current horizontal value of Cursor 1 to zero touch the Set Curt Zero selector A A delta is displayed in the status area of the Cursor Type selector indicating that cursor measurements are made by subtracting that value This is useful in TDR and TDT measurements Touch Clear Cursors to return to normal mode Touching Set Zero Rho enables you io position the cursors on a portion of the trace that you wish to be used as the zero rho or 50 O position Set Zero Rho is not selectable unless Y Units is set to Rho in the Graticules pop up menu To undo the effect of setting ze
189. ects the peak to peak or RMSA standard deviation statistic for the Noise and Jitter measurements The Dispersion parameter does not affect the Signal to Noise Ratio measurement in in a Distal The distal most distant from the origin voltage level Rise and fall times are measured between the proximal and distal voltage levels which are typically 10 and 90 of the baseline to topline voltages May be set as a relative per cent an absolute volts value or a delta voltage from the baseline or topline al Filtering The number of successive samples that must cross a threshold level before the transition is considered valid Noisy sig nals wiii be most affected by filtering i Harmonic For frequency domain measurements Number used with the harmonic search mode See Search Mode below y Histogram The number of points in the histograms Points taken for Jitter and Noise measure ments This parameter cannot be ad justed but appears in the Jitter and Noise pop up menus as Hist Pts y Jitter Level The level at which the Jitter measure ment is taken in volts This parameter cannot be adjusted but appears in the Jitter pop up menu as ditt Lvl This pa rameter will be affected by the Jitter Location setting CSA 803A User Manual 3 151 Measurements Table 3 12 Measurement Parameters Coni SW HW Stat Name Definition i Jitter The location of the histogram for the Location Jitter measurement May be
190. ed trace sam ples as opposed to hardware measurements that are captured by special circuitry that monitors the signals directly Glossary Glossary Smoothing Processing applied by the sampling head prior to the digitization of a trace to reduce apparent noise With smoothing the sampling head sampies the signal 8 times instead of once and the average of the samples is then used by hardware measurements and the digitizing circuitry Statistical Measurement An automated measurement that is derived from color graded waveform data and is based on histograms computed at the crossing levels A statistical measurement can be selected only in color graded display mode Stored Trace A coliection of sampled points that constitute a single trace acquisition that is saved in memory Time Base The time dependent specifications that control the acquisition of a trace The time base determines when and how long to acquire and digitize signal data points Time Domain Reflectometry TDR A method of characterising a transmission line or network by sending a signal from one end and monitoring the electrical reflections Trace The visible representation of an input signal or combination of signals identical to waveform Trace Expression The definition of what the trace displays It can include one or more channels combined arithmetically and modified by functions Trace Number A number assigned by the CSA 803A to identify a trace
191. el Selector in the Knob Menu 0O Step 29 Touch the vertical icon and the Chan Sel selector in the Knob menu until it displays Trace Sep C Step 30 Turn either knob and observe the selected window trace move up or down Operating Basics Horizontal Reference Point CSA 803A User Manual Example 3 Defining Complex Traces Up to now whenever you have changed the horizontal size of a trace the left edge remained in place and magnification occurred around it You can change the anchor point of a trace to either the center or the right edge by using the Horizontal Desc pop up menu Cj Step 31 Select the main trace top graticuie by touching it Touch the horizontal icon lt gt and use the bottom knob to position a critical portion of your trace at the center of the graticule Turn the top knob left and right one click at a time and observe that the critical part moves End by re establishing the original position with the critical portion of the trace centered C Step 32 Press the WAVEFORM button in the MENUS column touch Horizontai Desc in the major menu and Center in the pop up menu Turn the top knob left one click at a time Observe that the critical center part of the trace remains stationary Note that the L next to the horizontal icon changes to C to remind you that the reference point is the center of the screen 2 41 Example 3 Defining Complex Traces 2 42 Operating Basics Example 4 Using Signal
192. emonstrates the TDR Time Domain Reflectomeiry feature of the SD 24 sampling head TDR is a method of examining and measuring a network or transmission line by sending a step into the network and moni toring the reflections For this example you will need an CSA 803A with at least one SD 24 in stalled Also you will need one SMA cable preferably of 5 ns length C Step 1 Initialize the CSA 803A press UTILITY touch Initialize and touch Initialize again Step 2 Attach one end of the cable to any SD 24 sampling head input Leave the other end unattached k ae Not Connected Figure 3 93 Connections for Example C Step 3 Press the SELECT CHANNEL button on the sampling head input channel to which you have connected the cable You see only a flat trace on the display because there is no signal on the channel But when the TDR feature is used the sampling head supplies the signal for you As with the calibrator signal the TDR step is synchronized with the internal clock E Step 4 Press the WAVEFORM button and touch the Sampling Head Fne s selector C Step 5 To turn on TDR touch TDR Preset The TDR Preset function acts to turn on the step generator for the selected channel creates a trace from that channel sets the graticule to rho scaling turns on base line correction and autosets the TDR waveform The sampling head will turn on a red light next to the channel input connec tor indicating that TDR is ac
193. eoeff 1 weoeff 2 weoeff 3 m Blackman 0 42 0 5 0 08 0 2 Biackman Harris 0 35875 0 48829 0 14128 0 01168 3 Hamming 0 54 0 46 0 0 1 Hanning 10 5 0 5 0 0 1 Rectangular 1 0 0 0 0 0 Triangular 0 5 0 0 0 1 3 For the nth harmonic magnitude compute the harmonic frequency and apply the previous algorithm In Peak Search Mode apply the FFT interpolation algorithm and mag nitude correction to the spectral component which is the nth peak of the FFT magnitude waveform Total Harmonic Distortion THD See also Frequency Domain Measuremenis on page D 16 d 2 D 22 Determine the fundamenta frequency Find the magnitude of the spectral peak and of adjacent values S 1 S S Din the FFT magnitude waveform SE DY SE DY Bp MO a a Se es D Find the first n harmonic components and determine the three highest waveform points in the FFT magnitude waveform S 1 S S J compute n S 1 S 1 An SD Se T SO a SE AD n 2 10 Compute Total Harmonic Distortion 2 2 THD J 2 A cite GOP se Ax a fT Appendices Statistical Measurements CSA 803A User Manual Appendix D Algorithms Under Shoot UnderShoot 100 x 2aseline Min l topline baseline If the values of topline and baseline are equal the measurement value will show error Width 1 Search the measurement zone for the leftmost mesial crossing of posi
194. equipment or other property n statements identify conditions or practices that could result in personal injury or loss of life These two terms appear on equipment m CAUTION indicates a personal injury hazard not immediately accessible as one reads the marking or a hazard to property including the equip ment itself a DANGER indicates a personal injury hazard immediately accessible as one reads the marking This symbol appears in manuals Static Sensitive Devices These symbols appear on equipment 4 A DANGER Protective ATTENTION High Voltage ground earth Refer to terminal manual CSA 803A User Manual Appendix C Safety Specific Precautions Observe ail of the following precautions to ensure your personal safety and to prevent damage to either the CSA 803A or equipment connected to it Power Source The CSA 803A is intended to operate from a power source that will not apply more than 250 Vams between the supply conductors or between either supply conductor and ground A protective ground connection through the grounding conductor in the power cord is essential for safe system opera tion Grounding the Instrument The CSA 803A is grounded through the power cord To avoid electric shock plug the power cord into a properly wired receptacle where earth ground has been verified by a qualified service person Do this before making connec tions to the input or output terminals of the CSA 803A With
195. er You can display only the measure ments for the selected trace however Table 2 1 compares the three types of measurements It will help you deter mine the best measurement type for your application Hardware measurements are specified using another alternate menu from the Measurements pop up menu C Step 21 Touch the Measurements selector in the major menu then touch Hardware Mode in the pop up menu 2 62 Operating Basics Example 5 Taking Automated Measurements Table 2 1 Measurement Mode Comparison Software Hardware Statistics Functions Ail measurements except Noise Jitter and SNR available Limited to 7 timing Full range of mea measurements surements avail able except fre quency domain measurements Trace Complexity Display Restrictions Resolution Speed All trace expres sions supported Not for random data such as eye patterns Any display mode Affected by dis played vertical size and trace functions e g averaging and smoothing Slower Only traces with out arithmetic operators or func tions are allowed Averaging and enveloping are allowed but the measurement is taken from unav eraged samples Not for random data such as eye patterns Any display mode Unaffected by dis play or functions Sampling head smoothing will affect hardware measurements Faster All trace expres sions that include an active trace are
196. er required Initial window delay lt 23 ns to 50 ms in steps of 1 of main record size Strobe skew adjustment 1 5 ns Table B 5 CSA 803A Display Specifications Characteristic Specification CRT 81 2 inch diagonal color magnetic deflection Vertical raster orientation Nominal screen size 6 087 inches vertical by 4 496 inches horizontal Character display Character height 0 10 in upper case Character cell 16 pixel vertical by 10 pixel horizontal Table B 6 CSA 803A AC Line Power Specifications Characteristic Specification Voltage ranges 90 to 132 Vans or 180 to 250 Vans Voltage ranges apply to trace distortion which reduces peak line voltage 5 Frequency 48 Hz to 440 Hz Power 320 W Current 4 6 Arms at 50 Hz 90 V line with 5 Fuse clipping 6 A 250 V normal blow CSA 803A User Manual B 5 Appendix B Specifications B 6 Table B 7 CSA 803A Environmental Specifications Characteristic Temperature Operating Non operating Humidity Altitude Operating Non operating Vibration Shock Bench handling Packaged product vibration and bounce Drop of packaged product Electrostatic immunity Specification Meets MIL T 28800E Type Ill Class 5 0 C to 50 C 40 C to 75 C Up to 95 relative humidity at up to 50 C Meets MIL T 28800E Type Ill Class 5 Up to 4 5 km 15 000 ft Up to 15 km 50 000 fi Operating sampling heads not installed
197. erent tests or parts You can also teil the CSA 803A to save the current measurement readouts as the reference values for those measurements If you then turn on the compare feature you can observe how much the signal deviates from those references as you tune the circuit under test NOTE If you change the axis units on a trace for example from volts to rho the reference values are not changed to match the new units Be sure the reference value is stored with appropriate units lt When the compare mode is on and measurement readouts show difference values the measurement readouts show a delta A in the selector label to remind you that difference values are being displayed For example the RMS measurement readout in the major menu area becomes the ARMS readout when compare mode is turned on Measurement reference values are stored separately for each trace The reference values you establish for one trace will not affect the reference values for other traces The compare feature affects all measurements on all traces When you turn on compare mode all measurement readouts show A comparison values even if you select a different trace Compare mode is turned on or off using the Compare amp References pop up menu in the Measure major menu You set the reference values to the current measurement values by touching the Save Current Meas Values as References selector See Figure 3 68 When you touch this selector ail the refe
198. ertical size and offset of a trace on a window time base the Chan Sel selector at the lower right of the display can be used to specify the individual channel to adjust and to specify Trace Sep or trace separation This vertical offset control lets you move a window trace up or down to visually separate it from other window traces or the main time base trace 3 221 Vertical Controls 3 222 Reference CSA 803A User Manual Windows A window trace is a trace that represents a portion of another trace that is magnified horizontally A window trace is sampled separately from the main trace it is magnifying Windows are created by touching the Window icon above the graticule When you touch the Window icon the CSA 803A creates a second graticule to show the window trace The portion of the main trace that is windowed is highlighted The display in Figure 3 109 is the result of touching the Window icon when the top trace was displayed alone on a single graticule display OE each E sent enol eaten os bE JERS PAKS lt div S2 16ns Figure 3 109 A Window Trace Display The window trace has the same trace expression as the main trace The difference between the two is the time base that each uses the main trace uses the main time base while the window traces uses a window time base The Horizontal Desc selector in the Waveform major menu always shows the time base of the selected trace A window trace is independent of the ma
199. es Appendix B Specifications Table B 14 CSA 803 Environmental Specifications Characteristic Specification Temperature Meets MIL T 28800E Type Ill Class 5 Operating 0 C to 50 C Non operating 40 C to 75 C Humidity Up to 95 relative humidity at up to 50 C Altitude Meets MIL T 28800E Type Hl Class 5 Non operating Up to 15 km 50 000 ft Vibration Operating sampling heads not installed meets MIL T 28800E Type Ill Class 5 section 4 5 5 3 1 Shock Non operating sampling heads not installed meets MIL T 28800E Type lil Class 5 section 4 5 5 4 1 Bench handling Operating meets MIL T 28800E Type lil Ciass 5 section 4 5 5 4 3 Packaged product vibration Packaged product sampling heads not and bounce instalied meets NSTA Proj 1A Drop of packaged product Packaged product sampling heads not installed meets NSTA Proj 1A Electrostatic immunity No disruption or degradation of performance up to 10 kV No damage to instrument up to 20 kV CSA 803A User Manual B 11 Appendix B Specifications Appendices Symbols and Terms Appendix C Safety Please take a moment to review these safety precautions They are provided for your protection and to prevent damage to the CSA 803A This safety information applies to all operators and service personnel These two terms appear in manuals a statements identify conditions or practices that could result in damage to the
200. es are being started or stopped caus ing the trace to shift vertically Baseline Correction automatically turns on when TDR Preset or Differential TDR Preset is selected in the Sampling Head Fne s menu In the Graticules pop up menu Baseline Correction also turns on when Rho is selected it turns off when Volts is selected Horizontal Axis Units To change the horizontal axis units use the Graticules pop up menu in the Waveform major menu The section of this pop up menu labeled X Units governs the horizontal axis units You can touch the Seconds Meters Feet or inches selectors to set the horizontal axis labels to those units The current setting is highlighted The Propagation Velocity selector assigns the knobs to let you specify the fraction of the speed of light at which the signal passes through your trans mission line or network Propagation velocity only applies to axis units of distance and does not apply if your horizontal axis units are seconds Propagation velocity is relative to an air line transmission cable so a setting of 1 0 indicates that your transmission line or network passes signals at the same speed as an air insulated cable The default value of 0 7 applies to most 50 Q SMA coaxial cables with plastic dielectric Reference Hardcopy A variety of printers and plotters are supported for producing a paper copy of the display This section will cover how to configure your system for most printers Also refer
201. es have been acquired See Figure 3 48 CSA 803A User Manual 3 99 Histograms i H i Cantinuae Figure 3 48 The Persist Histograms Pop up Menu 3 100 Reference Displaying a Histogram CSA 803A User Manual Histograms To turn on the histogram display press the DISPLAY MODES button touch Persist Histogram and then touch either the Vertical Histogram or Hori zontal Histogram selector This changes the display mode to infinite persist ence if the current mode is normal or variable If the current display mode is color graded it won t change When the histogram display is turned on the waveform record length is set to 512 points If the record length was greater than 512 you will see a message informing you of the change in record length A rectangular box used to specify the section of the selected trace used to generate the histogram is displayed when histograms are turned on ifthe display is in color graded mode when the histogram display is turned on the histogram is initialized with data from the color graded display Note that the color graded display does not make a distinction between the selected trace and non selected traces when the histogram is initialized with data from the color graded display Thus it is possible to get samples from non selected traces in the histogram data if the histogram box encom passes any non selected trace Therefore when using the color graded mode display only
202. es selector You cannot delete a stored trace if it is being used as part of a displayed trace In Figure 3 87 stored trace 1 is used in the trace definition of dis played trace 3 The selector for stored trace 1 cannot be selected Figure 3 87 The Delete Trace Pop up Menu 3 184 Reference Displaying Time and Date with Stored Traces Stored Traces You can display the time and date that a trace was stored by selecting Stored Tra Time Date in the Instrument Options pop up menu of the Utility major menu The time and date for each stored trace appears in the stored trace selectors Time and date can be displayed with stored traces regardless of whether Stored Tra Time Date was on when the traces were stored When the Stored Tra Time Date display is on the time and date stamp appear underneath any stored trace selector in all appropriate pop up menus including the Recall Trace and Delete Trace pop up menus in the Store Recall major menu the Vertical Desc and Horizontal Desc pop up menus in the Waveform major menu and the Labeling pop up menu in the Utility 1 major menu CSA 803A User Manual 3 185 Stored Traces 3 186 Reference System Identification You can determine the configuration of your system by looking at the Identify pop up menu in the Utility major menu See Figure 3 88 7 En an ys fa a ie dad at System Identification CSAG SA Mainframe he BALABSSB Executive Processor eE i M
203. esting pop up menu and touch Set N Wfms see Figure 3 65 This assigns the knobs to limit the number of waveforms acquired in the same fashion that Pass Fail testing works The range for the number of waveforms acquired is 1 to 292 approximately four billion To begin conditional acquisi tion touch Stop N Wfms Acquisition will stop when N waveform records have been acquired The number of waveforms left to acquire is shown in the lower left corner of the display CSA 803A User Manual 3 131 Mask Testing Thus without using Pass Fail testing there are two steps to stop acquisition based on the number of waveforms acquired C Step 1 Set the number of waveforms using Set N Wfms C Step 2 Begin the acquisition by selecting Stop N Wfms If you want to stop the acquisition before the conditional acquisition com pletes press RUN STOP Number of waveforms left to acquire is shown here Figure 3 65 Using Stop N Wims 3 132 Reference Standard Mask Definitions and Requirements CSA 803A User Manual Mask Testing The following three tabies define the 38 standard telecommunication masks that are stored in the CSA 803A CCITT G 703 Electrical Standards Masks Signal Requirements 75 Q signals require a 75 to 50 O converter with signal attenuation entered Table 3 6 CCITT G 703 Electrical Standards Masks Mask Name Data Rate Trigger Data Signal Signal Symmetrical 2 048 Mb s Same as data 1200 AIS
204. et the number of waveforms or samples using Set N Wfms or Set N Samples C Step 2 Begin the acquisition by selecting Stop N Wfms or Stop N Samples If you want to stop the acquisition before the conditional acquisition com pletes press RUN STOP The data that appears in the histogram readout is calculated as waveforms are acquired The histogram display is updated based on the Refresh Rate 3 103 Histograms Number of waveforms or samples left to acquire is shown here Figure 3 49 Using Stop N Wfms Changing the Display Update Rate The rate the histogram display is updated can be varied from zero seconds to three minutes 180 seconds To change how often the histogram display is updated touch Refresh Rate You can now turn either of the control knobs to change the time between updates or you can use the knob pop up menu to enter the time directly With the knobs you can vary the update rate from 5 to 180 seconds With the knob pop up menu you can enter zero seconds Setting the dis play update rate to zero seconds allows the instrument to build the histo gram more rapidly until the number of waveform samples equals the num ber set by Set N Samples or the number of waveforms acquired equals the number set by Set N Wims The instrument then displays the acquired histogram 3 104 Reference CSA 803A User Manual Histograms Changing Scaling You can set the histogram scaling to either linear or log
205. etting between On and Off a Trigger Holdoff displays a pop up menu that allows you to select auto or manual holdoff mode See Figure 3 105 For Auto mode the trigger holdoff is automatically programmed to the minimum possible holdoff value shown under Actual Holdoff This value is slightly beyond the rightmost point acquired in the Main record For Manual mode you can select a trigger holdoff under Requested Hoildoff to extend the trigger holdoff to periods longer than the auto mode minimum value up to 2 5 seconds Touching the Holdoff Mode toggles the setting between Auto and Manual modes In Auto holdoff mode the Actual Holdoff setting for the trigger ignores Requested Holdoff and depends only on the timebase settings Actual Holdoff is updated when the assigned values for Main Size and Main Position change in order to hold off retriggering to a point beyond the rightmost point acquired in the Main record The minimum value for Actual Holdoff is 5 ps In Manual holdoff mode the Actual Holdoff setting for the trigger takes into account the value of Requested Holdoff in addition to the timebase settings The result is always a longer Actual Holdoff in manual mode than in auto mode The value of Requested Holdoff must be between 5 us and 2 5 seconds Touching Requested Holdoff allows you to enter a new value for requested holdoff CSA 803A User Manual 3 215 Triggering Figure 3 105 The Trigger Major Menu and the T
206. f measurements that you select This sample menu shows that the measurement system is set up to take six measurements on the selected trace See page 3 137 UTILUFY Use this pop up menu to make your measurement relative to a reference value See page 3 147 CSA 803A User Manual 1 27 At a Glance Display Modes Major Menu This menu enables you fo select several kinds of display persistence g and to control the histogram display Use this menu to generate or edit masks See page 3 43 used in mask testing See page 3 119 j Persistence Histograme i i Mask Testing i jdefined Undefined WAVEFORM TRIGGER MEASURE DISPLAY MODES STORE RECALL ARSI SONET lt COTY SPH Unstical standarde UTILIFY Rent inueu A ee NS This menu show the density values of the color graded display See page 3 45 Tia hl Ec spall at ait inte bl face Naat pei le epee nth anand Use this menu to select predefined telecommunication masks for mask testing See page 3 119 1 22 Geiting Started At a Glance Store Recall Major Menu These pop up menus let you store and recall displayed traces See page 3 181 Penner nen Te ea gpg te Re fecali Stored Trace i i Haanen ncn stile RAM S4490 bytes WAVEFORM m MEASURE L DISPLAY MODES STORE RECALL This selector activates or disables the SEQUENCE S
207. fic values or change the knob resolution CSA 803A User Manual 3 15 Averaging and Enveloping Limiting Acquisition Side Effects of Averaging and Enveloping You can have the CSA 803A stop acquiring trace data when enough data is accumulated to determine a complete average or envelope This has the effect of freezing the trace The selectors in the Stop Acquisition On section of the Acquire Description pop up menu let you specify One Record Aver age Complete Envelope Complete or Both Avg amp Env When you want to resume normal continuous acquisition touch the Continuous selector Averaging improves the accuracy of some software measurements because the measurements are taken from averaged data However some measure ments can be adversely affected by averaging or enveloping For example if you take a rise time measurement of a signal with horizontal jitter the aver aged trace will indicate an inaccurately slow reading Be cautious when taking software measurements of averaged or enveloped traces One way to take an accurate rise time measurement on a signal with jitter is to use statistical measurements on the unaveraged signal Hardware measurements are unaffected by averaging or enveloping be cause these measurements are taken directly from the signal Reference Example CSA 803A User Manual Baseline Correction Baseline correction holds the vertical position of a trace on the display while the signal is chan
208. fore the extended diagnostics were entered In the case where extended diagnostics were entered after power on the instrument will return to the state it was in when last powered off The top portion of the Extended Diagnostics menu shows three columns with the status of the diagnostic tests SUBSYSTEM IND FAULTS a Executive WEAK b Display till c Time Base kkk d Main Acq KREY Figure 3 18 The Top Portion of the Extended Diagnostics Menu 3 38 Reference Diagnostics if the extended diagnostic system has been entered because of a test failure the asterisks in the INDEX column will be replaced with test results The three columns of this display have the following meanings a SUBSYSTEM lists the names of the subsystem tests a INDEX shows the test status for each subsystem Four asterisks indicate the subsystem tests have yet to be executed The word pass indicates al tests in this subsystem have executed successfully Any other number or letter sequence indicates a diagnostic failure NOTE Do not rely on any measurements taken from an instrument that does not pass all extended diagnostics Call your service person for repair m FAULTS shows the number of tests in the subsystem that failed Running ail of the extended diagnostics takes about 40 seconds depend ing on system configuration You may execute ail the tests from the ex tended diagnostics menu by touching the x All selector to set the all par
209. frame Channels Being Entered Channel Selectors Numeric Keypad Trace Functions or Stored Traces Syntax Selectors Figure 3 100 The DefTra Pop up Menu e Stored Traces list all the traces that have been stored in the CSA 803A For a discussion of stored traces see Stored Traces on page 3 181 This area of the menu is shared with the trace functions selectors described above If the Stored Traces selector is highlighted the stored trace selectors are shown Touch the Stored Traces selector to highlight it if the trace functions list is shown Syntax Selectors and let you specify the order of mathematical operations Each opening parenthesis must be matched with a closing parenthesis Use the selector to separate arguments to functions that require more than one argument as does Smooth Use Back Space to correct errors as you enter the trace expression Always finish your trace expression by touching the Enter Desc selector Cancel allows you to leave the DefTra pop up menu without implementing the trace expres sion entered Cancel can be selected at any time NOTE All trace functions have an opening parenthesis You must use a closing parenthesis to enclose the function arguments CSA 803A User Manual 3 205 Trace Definition and Management Using Trace Functions in Trace Expressions Trace functions operate on argumenis which are usually channels or trace expressions The function is applied to eac
210. fset move the trace up or down on the display This is called adjusting the verti cal offset To do either touch the vertical 4 icon this assigns the knobs to adjust the vertical size top knob and offset bottom knob of a channel of the selected trace If you want to change the size or offset of a different trace touch the desired trace to select it Then use the knobs to adjust vertical size and offset NOTE Touch a knob label to display the keypad pop up menu This lets you set vertical size and offset numerically or quickly set them to maximum or minimum limits It also lets you set the knob resolution Adjusting Channels and Adjusting Traces When you adjust the vertical size or offset of a trace acquired in Fast mode you are adjusting the size or offset of one of the channels that is in the trace expression If the trace you are adjusting has the trace expression M1 M2 you can adjust the vertical size of only one channel at a time This has the following side effects w Changing the channel size or offset for this trace changes the channel size or offset for all the other traces that display that channel ifthe trace you are adjusting has more than one channel in its trace expression changing the vertical size of one channel does not change the size of the other channeis If the vertical scale factors of all the channels in a trace do not match the vertical size of the trace is undefined For example in the case of
211. g heads you can use the knobs to calibrate manually See Figure 3 22 NOTE Use enhanced accuracy only when the instrument temperature has stabilized it takes 20 minutes for the CSA 803A to completely warm up Figure 3 22 The Enhanced Accuracy Major Menu The Enhanced Accuracy menu is selected from the Utility major menu by selecting Page to Enhanced Accuracy The eight selectors in this menu fall into these categories Control of Automated Calibration the Time Base Cal Mode selec tor controls the internal time base automated calibration system You can select among Fast High Precision Off or Once The Delay Com pensate selector in the Delay Adjust pop up menu controls operation of the automated delay adjustment Calibration Assistance the Calibrate All selector helps you quickly calibrate a sampling head channel as well as deskew sampling head delays Sampling Head Calibration the Blowby Compensate Gain Offset TDR Amplitude and Delay Adjust selectors let you calibrate sampling head parameters You can make each of these calibration adjustments automatically with instrument assistance or you can make each calibra tion manually using the knobs 3 49 Enhanced Accuracy Control of Automated Calibration 3 50 The CSA 803A automatically calibrates the internal time base and vertical amplifiers without your intervention You can specify whether you want the calibration optimized for accuracy or for s
212. ge Power Switch Selector Fuse Power Cord Connector Figure 1 2 Rear Panel Power Connectors and Switches The PRINTER connector provides a Centronics style interface so you can connect a printer to the CSA 803A This lets you make a paper copy of the display by pressing the HARDCOPY button on the front panel The RS 232 C DCE connector lets you connect a computer terminal or modem to the CSA 803A The GPIB section similarly has an IEEE STD 488 PORT connector Both of these connectors iet you make the CSA 803A part of an automated test and measurement system Hardcopy information can also be routed through either the RS 232 C or the IEEE STD 488 PORT connector See Figure 1 3 1 7 Introduction 1 8 GPIB RS 232 C IEEE 488 Printer Figure 1 3 Rear Panel Printer and Data Connectors Getting Started Introduction Installation Follow this sequence when you instali the CSA 803A O Step 1 2 Set the PRINCIPAL Set the nee panel POWER SWITCH to ON STANDBY OFF switch to STANDBY Step 3 Step 4 Set the LINE VOLTAGE Install sampling SELECTOR to the heads in the proper range for your front panel system compartments 0 Step 5 Connect the power cord from the POWER connector to your power system 0O Step 6 Set the PRINCIPAL POWER SWITCH to ON CJ Step 7 Set the front panel ON STANDBY ai hg Once the CSA 803A is installed use the ON STANDBY switch as a power switch
213. ging This feature is most useful in TDR measurements because changes in transmission line impedance affect the vertical place ment of the trace When baseline correction is first turned on the left most region of the se lected trace is examined and the vertical screen placement of this trace segment is determined The left most region is the region of samples soon est after the trigger and may or may not be shown on the trace display Thereafter the baseline correction feature periodically examines this left most region of the trace and automatically adjusts the vertical position to move that portion of the trace to its established vertical placement Select the Waveform major menu to access the Graticules pop up menu Touch the Baseline Correction selector in the Graticules pop up menu to turn baseline correction on or off Baseline correction works on all channels up to 4 in all defined traces Baseline Correction is automatically turned on when Rho is selected for Y Units and turned off when Volts are selected for Y Units The following example shows the value of Baseline Correction _ Step 1 Turn baseline correction off C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A C Step 3 Using an SD 24 sampling head establish a TDR display of a short unterminated cable Position the trace horizontally so that the first rise does not occur to the left
214. gs of the 30 and 30 levels and build a table of these crossings 7 Using the table built in step 6 qualify the original waveform data into topline baseline and ignore points 8 The topline value is the average of ali the points in the topline group 9 The baseline value is the average of all the points in the baseline group Amplitude Amplitude topline baseline Areat ished py 1 RI ABS w j R y jem where m index of left most measurement zone sample n index of right most measurement zone sample WG input sampled data point R reference level measurement parameter T time interval between successive samples ABS the absolute value function Area Ot DEREWO R Area a as x 7 where m index of left most measurement zone sampie n index of right most measurement zone sample W j input sampled data point R reference level measurement parameter T time interval between successive samples CSA 803A User Manual D 13 Appendix D Algorithms D 14 Cross The cross measurement finds the left most crossing of the reference level of the proper slope that is within the measurement zone The horizontal posi tion of the crossing point is displayed Linear interpolation between vertical points and between time intervals is necessary to determine the crossing time when the reference level value does not correspond to acquired data Duty Cycle t Calculate the Period of the selected
215. gth of a trace increases the visual enhancement of trace vectoring becomes less evident When you display a 512 sampie trace with trace vectoring turned off the individual samples of the trace show as dots When you display a trace of more than 512 samples you can use horizontal magnification to achieve the same effect by displaying any 512 sample portion of the trace For informa tion about horizontal magnification see Pan Zoom on page 3 109 You turn trace vectoring on or off using the Instrument Options pop up menu in the Utility major menu Touch the Vectored Trace selector to set it to Off or On See Figure 3 107 Trace vectoring can also be turned on or off in the Persist Histograms pop up menu in the Display Modes major menu i Instrument Uptians l Hutaset Onticons Tate Antime Pawerups i j i Vectored Trace Selector Figure 3 107 The instrument Options Pop up Menu 3 218 Reference Vertical Controls The vertical controls let you set the vertical size and placement of your traces Touch the vertical icon to access these controls See Fig ure 3 108 Vertical Icon is ea we 1 fnere a ERE NN PCE SEEN Knob Labels Chan Sel Selector Figure 3 108 Vertical Controls CSA 803A User Manual 3 219 Vertical Controls Setting Vertical Size You can change the vertical magnification or size of a trace You can also and Of
216. gure 1 3 Figure 2 1 Figure 2 2 Figure 2 3 List of Figures Front Panel Connectors ccsipiciies gent ead eure hs es Rear Panel Power Connectors and Switches Rear Panel Printer and Data Connectors Utility Major Menu 2 0 0 0 2 00 Initialize Selector in Utility1 Major Menu Cable from the CALIBRATOR Output to a Sampling Mead WNDU er enan nE Sedu cis icine eeu one a pam tes Figure 2 4 Sampling Head Control Panel SD 24 shown Figure 2 5 The Trigger Major Menu and Source Pop Up Menu Figure 2 6 AUTOSET Sutton Location 22 20d scwatvoscseneene eos Figure 2 7 The Instrument Options Pop Up Menu Figure 2 8 The Calibrator Signal After Pressing AUTOSET in Edge M d mermar cs e aa Sou dous eat Soe tee ios ans CUED Figure 2 10 Figure 2 11 Figure 2 12 Figure 2 13 Figure 2 14 Figure 2 15 Figure 2 16 Figure 2 17 Figure 2 18 Figure 2 19 Figure 2 20 Figure 2 21 Figure 2 22 Figure 2 23 The Knob Menu and Keypad Pop Up Menu Connections for Example 2 0 cee cece eee The Acquired Calibrator Signal A Vectored Trace Display 0005 Graticule with Two Traces 2 cee ce eee eee The Waveform Major Menu with the Knob Menu The Trace Status Menu 2 6 6 eee ce eee eee The Labeling Pop Up Menu 00 0005 The Graticules Pop Up Menu 00 08
217. h between traces statistical measurements are limited to one trace per graticule Stored traces may be left on the dispiay they are ignored by the statistical measurement algo rithm Whenever making Statistics Mode measurements of an eye pattern trace set the Eye Pattern selector in the Measurements pop up menu to On All measurements except the three Frequency Domain measurements in the Measurements pop up menu can be taken as statistical measurements In software mode all measurements except Noise SNR and Jitter are available Only seven timing measurements Rise Fall Frequency Period Prop Delay Cross and Width can be taken as hardware measurements Duty Cycle and Phase are software measurements Jitter Signal to Noise Ratio and Noise are statistical measurements For example the Rise meas urement can be taken as a software measurement a hardware measure ment or a statistical measurement The RMS measurement is not a timing measurement and cannot be taken as a hardware measurement You cannot take measurements in different modes on the same trace You can however create two or three identical traces and take measurements in different modes on each You can display only the measurements for the selected trace at any one time Frequency Domain Measurements The frequency domain measurements Spectral Freq Spectral Mag and THD may be taken on FFT magnitude waveforms only These selectors are available on the Measurement
218. h individual sample of the trace The trace that is displayed is built from the function being applied to each sample Tabie 3 13 Trace Functions Function Trace Functions Abs The absolute value of the argument trace Avg The average of several trace record acquisitions of the argument The number of records acquired is controlled by the knobs after touching the Avg N selector in the Acquire Desc pop up menu NOTE Average and envelope can be applied to a trace that is already defined and being displayed See Averaging and Enveloping on page 3 13 Diff The differentia of the argument Env The limit of excursion of several trace record acquisitions of the argument The number of records acquired is con trolled by the knobs after touching the Env N selector in the Acquire Desc pop up menu Exp The natural antilog of the argument FFTmag The magnitude of the frequency spectrum of the selected trace FFTphase The phase of the frequency spectrum of the selected trace Filter Applies the Smooth function to a trace two times Like Smooth Filter has two arguments The first argument is the trace to be filtered the second argument is a rise time Each time Filter is evaluated the record length time per division and the specified rise time are used to calcu late the number of dots to be used in the smoothing algo rithm Filtering may be centered or shifted A centered filter is non
219. h the horizontal gt icon This assigns the knobs to adjust the horizontal size top knob and position bottom knob of the selected trace The axis label for the left edge of the graticule is slightly different than the horizontal position of a trace This is because traces extend slightly beyond the edges of the graticule The illustration on the previous page shows the main position the knob label is 59 5 ns and the left edge of the graticule is 58 5 ns If you want to change the size or position of a different trace touch the desired trace to select it Then you can use the knobs to adjust horizontal size and position NOTE Touch a knob label to display the Keypad pop up menu This lets you set horizontal size and position numerically or quickly set them to maximum or minimum limits It also lets you set the knob resolution Interactions With Other Traces The knob labels tell you whether the selected trace is from the main time base or a window time base All traces from the main time base share the same size and position If you change the size or position of one main trace you will change the size or position of all of main traces All traces from window time bases have the same horizontal size If you change the horizontal size of one window trace you will change the horizon tal size of all window traces Each window trace can have a unique horizon tal position Reference Pan Zoom CSA 803A User Manual
220. hat the SD 24 sampling head sends through the cable Readouts are displayed in units of impedance Q as well as in units of rho in the Cursors major menu Operating Basics CSA 803A User Manual Example 10 Taking TDR Measurements This example demonstrates the TDR Time Domain Reflectometry feature of the SD 24 sampling heads when they are used in combination with the CSA 803A TDR is a method of examining and measuring a network or transmission line by sending a step into the network and monitoring the reflections For this example you will need a CSA 803A with at least one SD 24 sampling head installed You will also need one SMA cable preferably of 5 ns length and a static protection wrist strap C Step 1 Initialize the CSA 803A press the UTILITY button in the MENUS column touch Initialize in the major menu and touch Initialize in the verification pop up menu O Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A _ Step 3 Attach one end of the cable to any SD 24 sampling head input Leave the other end unattached k it niji Cole eters Not Connected Figure 2 52 Connections for Example 10 O Step 4 Press the UTILITY button and select Instrument Options in the pop up menu Select Vectored Trace then Exit C Step 5 Press the WAVEFORM button and touch the Sampling Head Fne s selector See Figure 2 53 The
221. he CSA 803A repeatedly determines the reference baseline and you cannot adjust it When reference tracking mode is set to Topline or Off you can set the reference baseline or you can have the CSA 803A set it once by touching the Setup selector in the Prop Delay or Pulse measurement pop up menu 3 152 Reference CSA 803A User Manual Measurements Table 3 12 Measurement Parameters Cont SW HW Stat Name p E nd wo oy Zai wo o yo Reference Filtering i Reference Level i Reference Level Mode al Reference LM zone i Reference Mesial y Reference RM Zone Pad Reference Slope Reference SN Ratio Definition The filtering constant on the reference trace used for propagation delay and phase measurements The transition crossing voltage level May be set as a relative percent value an absolute volts value or a delta volt age from the baseline or topline The reference level affects the Cross mea surement and can also affect the Spec tral Frequency and Spectral Magnitude measurements See the Search Mode parameter The levei mode on the reference trace for propagation delay and phase mea suremenis The left limit of the measurement zone used in propagation delay and phase measurements on the reference trace The voltage level used in propagation delay and phase measurements on the reference trace May be set as a relative percent value an absolute volts
222. he hardcopy while the screen is still frozen by press ing the HARDCOPY button a second time The following table summarizes the factory default settings associated with each printer selection in the Hardcopy pop up menu These settings are not affected by initialization Table 3 5 Hardcopy Defaults Printer Screen Direction Data Output Port Format Format 8 pin HiRes N A N A Centronics 24 pin HiRes N A N A Centronics Tek 4692 Screen Vertical N A Centronics Tek 4696 Dithered Vertical N A Centronics Tek 4697 Dithered Horizontal N A Centronics Alt Inkjet Draft Horizontal N A Centronics HPGL HiRes N A N A Centronics The default settings for the color map associated with a color printer setting may be recovered by selecting Default Color Map in the Hardcopy pop up menu 3 97 Hardcopy 3 98 Reference Histograms The CSA 803A can display histograms constructed from the selected trace s waveform data You can display either a vertical voltage or horizontal time histogram Only one type of histogram can be displayed at a time See Figure 3 47 1S Figure 3 47 A Histogram Displayed on an Eye Diagram To create a histogram use the Persist Histograms pop up menu You can specify the section of the selected trace used to determine the histogram and set histogram scaling to either linear or logarithmic You can specify that acquisition stop after a set number of trace acquisitions or after a set num ber of sampl
223. he knob assignment remains until you change it or go to another major menu Be careful not to inadvertently change an earlier calibration Calibrating Gain Manually The Gain pop up menu is used to calibrate loop gain See Figure 3 25 This menu has one selector in addition to the standard ones for calibration pop up menus The Divide By Two Mode selecior turns the trigger divide by two mode on or off Normal operation of the CSA 803A internal clock requires that this selector be set to Off Set it to On only when calibrating loop gain This calibration does not apply to the SD 14 sampling head To calibrate loop gain manually first establish a display of the calibrator signal on the sampling head channel you want to calibrate Adjust the vertical size to 50 mV div and the horizontal size to 500 ps div Center the rising edge of the calibrator trace on the graticule See the illustration on the next page Touch the Divide By Two Mode selector to turn this mode On Adjust the calibration value to the display that aligns the single line portion of the trace with the bottom of the high amplitude portion If several settings qualify select the setting that gives the highest amplitude Remember to turn off the Divide By Two Mode after the loop gain has been calibrated 3 56 l Reference CSA 803A User Manual Enhanced Accuracy 1GOmY o oo frecpnnetasiale apne Paii Rrrr hahe GA d ng S6ane d iu 65 96ps Figure 3 25 Lo
224. help you display a con stellation diagram on the CSA 803A You will need the following equipment Atwo channel sampling head or two single channel sampling heads m 3SMA cables a A static protection wrist strap To display a constellation diagram perform the following steps o Step 1 Press the UTILITY button touch Initialize in the Utility major menu and then touch Initialize in the Verify Initialize pop up menu C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A O Step 3 Connect a cable from signal source 1 often called the P signal to Channel 1 for simplicity we assume you are using a two channel sampling head C Step 4 Connect another cable of the same length from signal source 2 often called the Q signal to Channel 2 C Step 5 Connect the third cable from your trigger source to the DIRECT trigger input on the front panel or to the PRESCALE trigger input Use the DIRECT input for signals of less than 2 5 GHz otherwise use the PRESCALE input for signals from 2 GHz up to 10 GHz Be sure not to exceed the maximum input voltage shown below each of the trigger inputs C Step 6 Press the TRIGGER button Touch the Source selector in the Trigger major menu Touch either External Direct or External Prescaler depending on the connector to which you connected your clock signal Touch Exit to remove the pop up menu E Step 7 Tur
225. his case will assign the second cursor to that trace and remove the menu C Step 17 Touch the selector in the pop up menu for the other trace on the display C Step 18 Move each cursor on its respective trace to a point halfway up the rising edge Use the fine knob control for precise positioning Some vertical noise is to be expected The major menu area shows the vertical and horizontal positions of both cursors It also shows the distance between the cursors along both axes The At readout shows the time between the leading edges which is the delay time you want to measure The automated measurement system can take the same delay measure ment if you want to see how this is done select the trace with the earliest transition and then press the MEASURE button Touch Measurements Hardware Mode PropDelay and Exit The measurement value will be displayed in the PropDelay selector in the major menu area but will show zero because only one trace is being exam ined To assign the second trace touch PropDelay and under the heading Second Trace at the bottom of the pop up menu touch the Trace n selec tor of the other trace Touch Prop Delay again to remove the pop up menu 2 72 Operating Basics Cursor Accuracy Considerations CSA 803A User Manual Example 6 Taking Delay Measurements Using Cursors Cursor measurements are limited to the resolution of the display Tips to help you get the most accuracy from measurements ar
226. histogram in order to calculate Amplitude Area Area or Energy The CSA 803A uses timing horizontal histograms to determine the crossing values for timing measurements The timing histograms have a height of 1 of the amplitude topline baseline of the waveform and are computed at the proximal mesial distal and reference levels Peaks in the histogram indicate crossings A peak must be at least 1 8 the height of the maximum peak to be recognized D 23 Appendix D Algorithms D 24 Jitter The Jitter measurement is available only in statistical measurement mode 1 Find the leftmost mesial crossing using timing histograms This horizon tal value is Cross 2 Find the second mesial crossing using the same method If a second crossing is found its horizontal value is Cross a Ifa second crossing was found center the histogram horizontal limits about the first crossing with a width equal to Cross Cross That is Cross Cross 2 Cross Cross 2 RightLimit Cross LeftLimit Cross b If no second crossing was found the histogram limits are the Left Limit and Right Limit of the measurement zone 3 Setthe top and bottom limits of the histogram at the mesial levei 4 Ifthe Jitter Location is set to Eye Cross and the trace was recognized as an eye diagram measure the jitter above and below the mesial to find the minimum jitter Otherwise calculate the jitter at the mesial Noi
227. ht and displays the Utility1 major menu as shown in Figure 2 1 Figure 2 1 Utility Major Menu Operating Basics Example 1 Displaying a Trace The Touch Panel You make selections from menus by touching the appropriate area Until you remove your finger from the display the CSA 803A indicates your potential selection by outlining that selector You can change your potential selection by dragging your finger to the desired selector before withdrawing it NOTE The CSA 803A does not perform any operation until you remove your finger from the display Menu Selectors The Utility major menu has eight selectors in ruled boxes The top half of each selector shows the name of the selector with a shaded background while the bottom displays the current status on a black background initialize Selector Figure 2 2 Initialize Selector in Utility Major Menu Selectors can be normal brightness like the ones you see in the Utility1 major menu A selector appears very dim if it cannot be selected in the current state Bright appearance indicates a selector is already selected or being used The Initialize selector operates when you touch it and withdraw your finger NOTE Be sure that the light beside the TOUCH PANEL button says ON This button is below the major menu buttons Cj Step 2 Touch the Initialize selector in the major menu area see Fig ure 2 2 Then touch the Initialize selector that is displayed in the p
228. i Boouracy Figure 2 7 The instrument Options Pop Up Menu L Step 11 Press the UTILITY major menu button in the MENUS column and touch the Instrument Options selector in the major menu if you see a different major menu than the Utility menu press the UTILITY button again The Instrument Options pop up menu controls autoset with the following groups of selectors Under Autoset Options you can turn on or off Vertical Autoset Hori zontal Autoset and Trigger Autoset which determine whether perform ing an autoset will alter those types of parameters If you want to set all three parameters to On use the Enable All selector u Under Autoset Mode you can select Period Mode or Edge Mode Period mode is the initialized default and displays several cycles of a trace Edge mode displays a single rising edge of the trace 2 10 Operating Basics Example 1 Displaying a Trace w The Stan Mask Autoset and Stan Mask Offset Adj selectors are used in performing autoset to the selected standard mask during mask testing Standard mask autoset is discussed in the Mask Testing section beginning on page 3 119 a The Undo Last Autoset selector restores the CSA 803A to the settings that existed before you pressed the AUTOSET button You want to display a single rising edge of the calibrator signal CJ Step 12 Touch the Autoset Mode selector in the pop up menu to set autoset to edge mode and press the AUTOSET button above the s
229. ibrated you can calibrate ali the channels including the reference channel You select the channel you want to cali brate using the selectors in the Selected Channel section of the Calibrate All pop up menu Then you touch the Calibrate selector to begin calibrating that channel The sequence for calibrating the sampling head channel is t A message prompts you to connect the calibrator output to the selected channel and touch the Proceed selector The CSA 803A automatically calibrates blowby gain and delay adjust 2 Another message prompts you to connect a 50 terminator to the selected channel and touch the Proceed selector The CSA 803A auto matically calibrates offset 3 Ifthe sampling head supports TDR a final message prompts you to connect a 50 Q terminator to the selected channel and touch the Pro ceed selector The CSA 803A automatically calibrates TDR amplitude Once a channel is calibrated you can select a different channel using the selectors in the Selected Channel section of the Calibrate All pop up menu and calibrate that new channel When you have calibrated a channel it is good practice to store its calibra tion values using the Store Constants selector This stores the current calibration values into sampling head non volatile memory When the system is powered on it calibrates the sampling heads to the values that were stored as constants If you later change the calibration values but do not store them the R
230. ien da 4 at HiSNR ug i Se H i de A E ee i Time Base Cantralier 2 94 i i Aequigition 4 g a2 Betiens LT Telecomm Standard Maske Tnstalted i Prescaler Nat Installed Figure 3 88 The Identify Pop up Menu The top portion of the Identify pop up menu shows the instrument serial number and the version numbers of the firmware programming for the various internal microprocessors The middle portion of the identify pop up menu shows which channels have sampling heads installed 1X 10X etc and which channels are not avail able OX For those channels that have sampling heads the sampling head type and serial number is shown The lower section of the Identify pop up menu shows instrument options and their respective states such as whether or not the option is installed CSA 803A User Manual 3 187 System identification 3 188 Reference TDR Step Generation CSA 803A User Manual TDR This section describes how to perform time domain reflectometry TDR measurements TDR measurements can be made only with an SD 24 TDR Sampling Head or an SD 20 Loop Thru Sampling Head none of the other SD Series sampling heads provide TDR capabilities Both channels in the SD 24 TDR Sampling Head have a step generator which gives both channeis TDR measurement capabilities You can use the outputs of both generators to perform differential and common mode TDR measurements The SD 20 Loop Thru Sampling Head is ca
231. igure 2 29 _ Step 9 Press the WAVEFORM major menu button in the MENUS column and touch Acquire Desc in the major menu O Step 10 Touch the Average N selector in the pop up menu then touch Exit to remove the pop up menu The averaged trace appears less noisy While the individual traces are being acquired the current record number is displayed in the Acquire Desc selector The trace expression shown in the Vertical Desc selector is Avg M1 showing that averaging has been added to your earlier expres sion You can change the number of records in an average from the default of 32 that was set by the initialization C Step 11 Touch Acquire Desc in the major menu and Set AvgN in the pop up menu Adjust the top knob to change the average count Each time you click the knob a new average begins If you wish the CSA 803A to stop acquiring data after the required number of sampies you can use the Average Complete selector in the section Stop Acquisition On C Step 12 Touch Acquire Desc in the major menu and select Average Complete in the pop up menu The CSA 803A stops acquiring data when the average is complete leaving a stable display see Figure 2 30 2 45 Example 4 Using Signal Processing Figure 2 29 The Acquire Desc Pop Up Menu ee pba ada ee tal ng A Iaia fa acy rds paad BL at te ee tg AE Fy Balle es eM hao Set rane ad a tattle ane ASAMA AE aA RN Aa aS Ares see en div
232. ilable from this menu To use the default mask as a base touch User Eye 9 9533Gb However you can select any eye mask that has exactly three components or use Edit Mask Defu to create masks 1 2 and 3 Standard masks with more or less components cannot be used After selecting the desired eye mask Reference Mask Testing you need to set the rate for the mask Touch Mask Testing touch the User Eye Rate selector and use the knob to set the desired rate Now proceed to edit the mask as described previously After editing the mask touch Create User Eye from the Mask Testing pop up menu The new user eye mask becomes a standard mask selectable from the Standard Masks pop up menu as User Eye and the instrument is abie to perform standard mask autoset to your user eye mask You can define and store many separate user eye masks with the Store Setting feature See Store Seitings page 3 175 for more information The following conditions apply to user eye masks m There must be three component masks a The three component masks are numbered 1 through 3 from the top to the bottom of the screen Masks 1 and 3 must extend from the extreme left to the extreme right of the display a There cannot be more than 24 vertices in all three component masks Each component mask must have at least three vertices CSA 803A User Manual 3 129 Mask Testing Starting Mask Testing After you have a user mask or standard mask selected the mask rema
233. ill stop after a new complete acquisition has been made for each waveform When you wish to resume normal continuous acquisition touch the Con tinuous selector under the heading Run Acquisition Acquisition 3 4 Figure 3 3 The Acquire Desc Pop up Menu Reference Clearing Traces CSA 803A User Manual Acquisition A trace may be displayed but not currently acquiring new trace data This happens if a trace is not triggered or if you use the ACQUISITION buiton to stop acquisition When the trace is displayed but is not acquiring data the trace record from the last acquisition remains on the display This is why traces appear frozen on the display when you turn ACQUISITION off You can clear the frozen trace data from the screen using the Clear Trace pop up menu in the Store Recall major menu This pop up menu is ilius trated on the next page To clear a trace touch the selector in the pop up menu that represents the trace you want to clear Traces are identified both by trace number and by trace expression and time base The Clear All selector lets you clear all traces at once You cannot clear a trace that displays only stored trace data For example if you have a trace that is defined to be T01 STO2 then that trace will not be listed in the Clear Trace pop up menu lf you clear traces that are being acquired live traces on the display they will be cleared and replaced with new trace data You
234. imum number of hits in any bin which for this algorithm must be at least 16 Table 3 1 A Sample Assignment of Colors to Hit Density Hit Density Default Color Maps To 1 2 Max to Max Pale Yellow Trace Color 1 1 4 Max to 1 2 Max 1 Rose Trace Color 2 1 8 Max to 1 4 Max 1 Purple Trace Color 4 1 16 Max to 1 8 Max 1 Light Blue Window Trace 1 to 1 16 Max Green Trace Color 3 To see the actual range of values represented by each color press Color Grad Scale in the Display Modes major menu The Color Grad Scale pop up menu shows the hit density for each of the five waveform colors The hit density readouts are updated when the CSA 803A updates the color graded display CSA 803A User Manual 3 45 Display Persistence Figure 3 21 The Color Grad Scale Pop up Menu Changing Colors There are five colors used in the color graded display The colors can be changed from the Color pop up menu in the Utility1 major menu The colors are mapped to the four trace colors and the window trace color To change the colors of the color graded display press the UTILITY button touch Color and change the appropriate trace color NOTE Changing display colors is described in more detail in Color Dis play on page 3 21 Although the four trace colors are assigned to traces in order as they are created you can change a trace s color assignment and thus the color used in the color graded display using the Trace
235. in the illustration below is greater than in the illustration on the previous page This window is especially useful for resolution of frequencies that are very close together Set the FFT Window selector in the Instrument Options pop up menu to Hamming to select this windowing function See Figure 3 38 eBdB MAS i in SEa Ny WN Peet a H ANA Pi y AA ar aa 2 of NY MM a AN Mn i ih Time Window Frequency Filter Figure 3 38 FFT Magnitude Displayed Using Hamming Window Reference GPIB Parameters The CSA 803A can be controlled by a remote computer through one of two interfaces These interfaces are industry standards IEEE Std 488 and RS 232 C IEEE Std 488 is also known as the General Purpose Interface Bus or GPIB This manual does not discuss the details of connecting a remote computer to the CSA 803A or the syntax and capabilities of remote commands That information is found in the CSA 803A and 11801B Programmer Manual GPIB Connection Connect the cabie from your GPIB controller computer to the IEEE STD 488 PORT connector on the CSA 803A rear panel See Figure 3 39 Three red lights show the internal GPIB status of the CSA 803A m SRQ Service Request is lighted whenever the CSA 803A activates the Service Request line This indicates to the controller that the CSA 803A has requested service a NRFD Not Ready For Data is lighted whenever the CSA 803A is not yet ready for the next data byte m N
236. in the lower half of the menu Letters are laid out as if they were on a standard keyboard The selectors beneath the characters allow you to choose Upper Case letters Lower Case letters Numbers which include some punctuation and symbols Graphics Greek letters or Other characters You can mix character types within a label As you type the label appears in the selector just below the trace or setting number A maximum of 10 characters can be used for a label Use the Back Space selector to correct errors as you type a label Touch Erase to completely erase the selected label Use the Exit selector to leave the pop up menu When you leave the pop up menu new labels are entered automatically If you want to enter a label without leaving the Labeling menu touch the selector for the labeled item in the menu You cannot use the same label for two items of the same type for example two active traces or two stored traces If you attempt to enter a duplicate label the error message Duplicate label label not changed appears on the display and the previous label is restored NOTE You cannot enter the same label for two items of the same type You can use automatic labeling if you don t want to enter labels yourself Automatic labeling labels the trace with its trace description For example if you turn on channel 2 the label attached to the trace will be M2 If you define a trace using the Def Tra pop up menu the label wil
237. in trace Once a window trace is established you can remove the main trace or move the window trace from graticule to graticule 3 223 Windows You can create more than one window trace from a single main trace You cannot create a window trace of a window trace if you remove all windows the display automatically returns to a single graticule display Changing Window You can change the size and position of a window trace just as you do with Size and Position any main trace Touch the lt gt or f icons to assign the knobs to horizontal size and position or vertical size and offset Complete information about horizontal size and position is on page 3 107 and vertical size and offset is on page 3 219 NOTE All window traces are the same horizontal size If you change horizontal size on one window trace you change horizontal size on all window traces All main traces share the same time base and so all have the same horizon tal size and position Each window trace has its own time base and so each can have a different horizontal position However all window time bases have the same horizontal size As you change the horizontal size or position of a window trace the high lighted portion of the main trace changes size and position This allows you to always see the portion of the main trace that the window trace is magnify ing In display modes other than Normal the main trace will not show a highlighted region Trace Se
238. ing Functions Windowing Highest Noise 3dB 6 dB Scallop Worst Function Side Band Band Band Loss Loss lobe width width width dB dB dB bins bins bins Rectangular 13 1 00 0 89 1 21 3 92 3 92 Triangular 27 1 33 1 28 1 78 1 82 3 07 Hanning 32 1 50 1 44 2 00 1 42 3 18 Hamming 43 1 36 1 30 1 81 1 78 3 30 Blackman 58 1 73 1 68 2 35 1 10 3 47 Blackman 92 2 00 1 90 2 72 0 83 3 85 Harris where bins refers to the frequency bins the even numbered points in the FFT waveform highest sidelobe is the minimum stopband attenuation which indicates how well leakage is blocked noise bandwidth is the equivalent noise bandwidth the width of an equivalent rectangular spectra response that would pass the same noise power as this windowing function 3 dB bandwidth and 6 dB bandwidth apply to the major lobe These affect the frequency resolution D 5 Appendix D Algorithms scallop loss is the attenuation of the windowing function at the odd numbered interpolated points in the FFT waveform worst loss is the worst case processing loss the sum of the scaliop loss and the equivalent noise bandwidth in dB Filter Filter n Smooth Smooth n Centered Mode Non Causal Filter Algorithm Smooth n avo S Wim h n x mo map forn lt h manh Smooth n aw 5 mn fork sns R 1 h Smooth n a gt Wim M 1 n x WM J m n h forn gt M 1 1 h where n index into
239. ins on the display However mask testing does not begin automatically To initiate mask testing display the Mask Testing menu Then select either Pass Fail Test or Count Mask Hits if you select Pass Fail Test the instru ment acquires a set number of waveforms and then looks for any sampile that falls inside the mask a mask hit One or more mask hits is a failure and Failure is indicated in red beneath the Mask Testing selector If there are no mask hits the instrument indicates Passing in green beneath the Mask Testing selector When you select Pass Fail Test the Set N Waveforms parameter defaults to 20 if the number of waveforms to be acquired N for the test is less than 10 or greater than 100 The instrument then turns on Count Mask Hits and also turns on Stop on N Waveforms If you select Count Mask Hits the instrument begins counting mask hits but does not indicate passing or failure Mask hit counts are allowed only in Infinite or Color Grading display modes If the display mode is either Normal or Variable when mask testing is initiated the display mode is switched to Infinite Persistence If the display mode is Color Grading then the display mode isn t changed If the display mode is Color Grading when mask test ing is turned on the mask count data is initialized with data from the color graded display Note that the color graded display mode makes no distinction between selected and non selected traces Thus if your mas
240. ion 1T To view the standard masks that are available assuming that this option is installed you first need to have a trace acquired With a trace acquired press the DISPLAY MODES button and then touch Standard Masks This brings up the Standard Masks pop up menu see Figures 3 58 and 3 59 This menu lists the masks available in four categories ANSI SONET CCITT optical standards CCITT G 703 electrical standards ANS 71 102 electrical standards and Miscellaneous standards On the menu eight masks are available under ANSI SONET CCITT optical standards The CCIT G 703 electrical standards masks total 18 and are contained on three pages Touch PAGE and PAGE to view the remaining CCIT G 703 masks available Ten ANSI 11 102 electrical standards are also available Lastly two masks are selectable under Miscellaneous standards the FDDI Halt mask and a User Eye mask i Forana aene Tha Electrical Standards Figure 3 58 The Standard Masks Pop up Menu 3 121 Mask Testing Figure 3 59 Pages 2 and 3 of the CCITT Electrical Standards As shown in Figure 3 59 the CCITT G 703 Electrical Standards masks are contained on three pages These pages overlap meaning that some masks are shown on more than one page Selecting a Predefined Mask To select a particular predefined standard mask first acquire a trace Stan dard masks cannot be selected if a user trace is not present With a trace displayed pre
241. isplay Using the FFTmag and FFTpha Icons You can display the magnitude of the frequency spectrum of a displayed trace by selecting the trace and touching the FFTmag icon The CSA 803A creates a second graticule to display the FFT magnitude of the trace Ifthe display already shows two graticules the FFT magnitude is displayed on the lower graticule Once you have created a display of the magnitude of the frequency spec trum the FFTpha icon appears above the lower graticule See Figure 3 28 Touch this icon to display the phase of the frequency components of the trace The FFT phase trace appears on the lower graticule The FFTmag icon E i H i wr ti H an is Pe eee j j i a pog i bts 3 Ty a erat 3 irataira rn a Mem aurea uit Figure 3 28 Location of the FFTmag Icon on the Display 3 67 Fast Fourier Transforms Am plitude Resolution Amplitude resolution is influenced by the windowing function used and by the vertical adjustment of the time domain trace For maximum amplitude resolution the time domain trace should be adjusted so that it is centered verticaily on the graticule and is as tall as possible without going beyond the graticule above or below Frequency Range The range and resolution of the frequency spectrum displayed by the and Resolution CSA 803A are determined by the sample interval and record length of the time domain trace The sample interval is displayed in the Horizo
242. it to remove the pop up menu 2 32 Operating Basics Trace Expressions CSA 803A User Manual Example 3 Defining Complex Traces You can display a trace that represents the difference between the two signals Up to now you have pressed the sampling head channel button to display a trace This is a short cut method limited to single channel traces The Defra icon creates new traces It is located above each graticule s upper right corner Touching the icon displays a pop up menu that covers the full display The same pop up menu is presented by the Vertical Desc selector of the Waveform major menu The menu selector allows you to view and change the expression of an existing trace while the DefTra icon cre ates a new trace NOTE The Vertical Desc selector and the DefTra icon operate differently though they both display the same pop up menu C Step 9 Touch the DefTra icon The selectors in this pop up menu are keystrokes that you use to build a trace expression see Figure 2 22 As you enter keystrokes the expression is shown at the top of the menu These selectors are available Channel Selectors specify an input channel NOTE You don t need to display the source traces to create a complex trace Numeric Keypad allows entry of numeric constants and arithmetic operators of addition subtraction multiplication and division a Trace Functions specify functions such as logarithms differentiation and averagi
243. ite persistence mode accumulated waveform data points remain on the screen indefinitely until some instrument set up change occurs which causes the process to start over For example infinite persistence is used in mask testing and if Clear Hits is selected during testing the waveform data is cleared and the mask count begins accumulating all over If any displayed waveform has a record length longer than 512 points when Infinite Persistence is selected the record length is set to 512 points and a message is displayed informing you of the change in record length Coior Grading This mode is similar to infinite persistence mode The only difference is that the accumulated points are color graded shaded with different colors to indicate the density of the points and a color graded database is built You can use the color graded database with histograms mask testing and statistical measurements You can also use color grading to provide more visual information about the trace Because the data at any point on the screen can change in this mode there is an additional control available in color grading mode that is not available for infinite persistence mode This is the Refresh Rate The screen is not refreshed after every acquisition instead the screen is refreshed at a specif ic user selectable rate The Refresh Rate controls how often the screen is 3 44 Reference Display Persistence updated with new data this also applies t
244. k overlaps a non se lected trace in Color Grading mode the mask will contain samples from the non selected trace To avoid this maintain enough vertical separation be tween traces to prevent overlap Masks are not allowed on stored traces though masks can be applied to calculated traces with stored components for example M1 STOQ1 In both Pass Fail and Count Mask Hits mode the mask count readout just above the Mask Testing selector begins displaying results There are three boxes located on the Display major menu which contain the mask count readout See Figure 3 64 The numbers in the three boxes are s Total number of hits data points within all masks w Total number of waveforms acquired a Number of hits in each mask Total is the sum of data points that fall inside a of the defined masks This number takes into account the overlap between masks That is if a sample fails into two overlapping masks the sample will be counted only once Wms is the number of waveforms which have been acquired 3 130 Reference Mask Testing To turn on mask counting select Count Mask Hits in the Mask Testing pop up menu Figure 3 64 Mask Count Readout Mask1 through Mask10 show the number of data points that have fallen inside the named mask When mask testing is initiated the readouts are active as long as Mask Testing is selected Mask Testing is highlighted Like the histogram dis play the counting is continue
245. knob to Right Limit Turning either knob will change the position of the assigned edge of the histogram box thus limiting the part of the selected trace used for the histogram The vertical and horizontal limits of the histogram box can be set without turning on the histogram display To set the size and location of the histo gram box without turning on the histogram display touch either Vertical Limits or Horizontal Limits first without touching either the Vertical Histo gram or Horizontai Histogram selector This way you can set up your histogram limits before you begin acquiring your data Histogram limits are set separately for each displayed trace And because a histogram applies only to the selected trace if you select a different trace the histogram display will disappear If you then reselect the original trace the histogram display will reappear This enables you to display several traces each with a different histogram display Remember that only one histogram that of the selected trace can be displayed at a time Histogram limits are expressed in axis units usually volts and seconds but are actually determined by screen position The histogram limits will remain fixed on the screen regardless of changes in vertical or horizontal size and position In color graded mode the histogram is initialized from the color graded database when the box limits change This will occur even when in Acquisi tion STOP mode Limiting
246. l be the trace description up to 10 characters To enable automatic labeling touch the Label Mode selector to set it to automatic When you store a labeled trace or create an active trace that displays a stored trace the label will be copied to the new trace unless this would duplicate a label on another trace in the same class 3 116 Reference Labeling Figure 3 56 The Labeling Pop up Menu Changing the trace description of an active trace will not change the label of the trace CSA 803A User Manual 3 117 Labeling Displaying Labels with Traces 3 118 Labels of displayed traces may be displayed on the screen with the traces When Displayed Traces is selected Display and Position selectors appear to the right of the trace selectors in the Labeling pop up menu Turning on Display will cause the labels to appear with the traces Labels will appear in the selectors for all traces whether Display is turned on or off Labels that are displayed on the screen move with the traces You can position each label relative to its trace Select Position to assign the knobs to set the vertical top knob and horizontal bottom knob position of the label The label position is relative to a specific point on the trace By chang ing the horizontal position of the label you are changing the point the label will follow By changing the vertical label position you can specify the verti cal offset of the label from the point
247. l in the Knob menu to select the other input channel Observe that the knob labels reflect the channel change O Step 20 Turn the top knob to the right to set the vertical size to 100 mV div You may need to turn the bottom knob to position the trace com pletely on the graticule Now the input channel traces and the complex difference trace are double their original size 2 37 Example 3 Defining Complex Traces High Precision If your complex trace is a high precision trace you can move it vertically Traces using the knobs without changing the offset of any component channel High precision traces are calculated using floating point arithmetic The complex trace you have created and moved in this example is not a high precision trace this is indicated by the notation of Fast in the Vertical Desc selector High precision traces will show High Prec in the Vertical Desc selector You can specify that ail traces you create in the future will be high precision traces Press the UTILITY button and touch the Instrument Options selec tor In the pop up menu touch the Trace Scaling selector until it shows Forced This does not affect any trace already on the screen but will cause all traces you create in the future to be high precision traces For this exam ple leave Trace Scaling set to Optional The remainder of this example will be clearer without multiple traces on the display L Step 21 Select and remove each of the simple t
248. lay adjust on the other There is no need to calibrate the reference channel manually Once you have determined the reference value you can calibrate the other heads to this value either manually or automatically To manually calibrate delay adjust on other heads first display the calibrator signal on the reference channel and note the horizontal position of the rising edge Then using the same signal cables and settings display the signal on either channel of the sampling head that you want to calibrate The top knob is assigned to the calibration value Adjust the calibration value so that the signal event is placed at the same horizontal position as on the reference channel You can specify whether or not the CSA 803A should automatically maintain the results of delay adjust Touch the Delay Compensate selector of the Delay Adjust pop up menu to set the delay adjust parameter to either On maintain delay adjustment or Off do not maintain the delay adjustment automatically 3 59 Enhanced Accuracy Offset for Sampling Sampling probes such as the SD 14 use an automated offset adjustment that sets both both offset null and offset gain Probes The offset null adjustment removes unwanted DC offset that may be present in the sampling probe This adjustment effectively zeroes the offset circuitry in the sampling probe so that a 0 V input signal delivers a 0 V output The offset gain adjustment matches the requested offset fro
249. le as listed in the pop up menu shown on the next page You may specify up to six measurements to be taken simultaneously on the selected trace C Step 7 Press the MEASURE button Figure 2 34 The Measure Major Menu The Measure major menu is displayed see Figure 2 34 initially this menu will appear mostly blank Six of the selectors are reserved for your measure ment readouts The Measurements selector brings up a pop up menu to let you choose which measurements you want see Figure 2 35 2 55 Example 5 Taking Automated Measurements Timia g Sr eqgRome ir Figure 2 35 The Measurements Pop Up Menu C Step 8 Touch the Measurements selector The Amplitude Timing and AreaEnergy sections of this pop up menu show ail the various measurements that you may specify Touch the selec tors in these areas to turn each measurement on and off When a measure ment is turned on that selector is highlighted in the menu Also one of the selectors in the major menu area displays that measurement value E Step 9 Touch the RMS and Frequency selectors This pop up menu does not disappear as soon as you select a measure ment so that several measurements may be turned on at one time The measurements are displayed but you may want to view the trace while watching the measured values CJ Step 10 Touch the Exit selector at the bottom of the pop up menu The readout areas of two of the selectors in the
250. le will show you how to use the two channels and step generators of an SD 24 to perform differential and common mode TDR measurements For this example you need at least one SD 24 installed in the left acquisition slot of the CSA 803A You also need one SMA cable preferably of 5 ns length Step 1 Initialize the CSA 803A press UTILITY touch Initialize and touch initialize again E Step 2 Attach one end of the cable to any SD 24 sampling head input Leave the other end unattached C Step 3 Press the SELECT CHANNEL button on the sampling head input channel to which you have connected the cable C Step 4 Touch the Sampling Head Fne s selector C Step 5 Touch TDR Preset C Step 6 Attach the loose end of the cable to the lower channel connec tor on the same sampling head 0O Step 7 Adjust the display size and position to show a trace similar to that shown in Figure 3 96 In Figure 3 96 notice that there is only one rising edge that of the incident TDR step There is very little or no reflection because the impedance of the termination in the receiving channel connector matches the impedance of the cable C Step 8 Press the SELECT CHANNEL button for the lower channel on the sampling head Adjust the vertical and horizontal settings to display the TDR step generated by the upper channel The horizontal distance separating the leading edges on the two traces is the time it takes the step transmitted by channel
251. lowed but the measurement is taken from unav eraged samples Not for random data such as eye patterns Any display mode Measurements are taken from a single trace re cord regardiess of display mode Unaffected by dis play or functions Only sampling head smoothing will affect hard ware measure ments Faster Full range of mea surements avail able except fre quency domain measurements All trace expres sions that include an active channel are supported For random data such as eye patterns Color graded mode only One active trace per graticule Affected by dis played vertical size and trace functions e g averaging smoothing and dual graticules Limited to 512 point record length Updated when color graded data base is updated selectable be tween 5 and 100 seconds or when a measurement parameter changes such as mesial level CSA 803A User Manual 3 145 Measurements 3 146 Use the Measurements pop up menu of the Measure major menu to select the measurement mode At the top of this pop up menu are three selectors Software Mode Statistics Mode and Hardware Mode The selector for the current mode is always highlighted Touch the selector for the mode you want When you select Hardware Mode the Amplitude Area Energy Duty Cycle Phase and Jitter measurement selectors do not appear If any of these measurements were established when you selected hardware measur
252. lt parameters or the parameters of another measurement such as Rise to move the left limit to the left of the first eye crossing If you use dual graticules each graticule has only 128 vertical values compared to 256 for a single graticule so set the vertical size as large as possible for better precision The time required to take statistical measurements can vary from a few hundred milliseconds to over a second depending on which measure ments are selected and what the measurement parameters are Whenever making Statistics Mode measurements of an eye pattern trace set the Eye Pattern selector in the Measurements pop up menu to On Refer to the table on the next page to determine the best measurement type for your application 3 144 Reference Measurements Table 3 11 Measurement Mode Comparison Software Hardware Statistics Functions Trace Complexity Display Restrictions Resolution Speed Ail measurements except Noise Jit ter and SNR avail able All trace expres sions supported Not for random data such as eye patterns Any display mode Measurements are taken from a single trace re cord regardless of display mode Affected by dis played vertical size and trace functions e g averaging and smoothing Slower Limited to 7 timing measurements Only traces with out arithmetic op erators or func tions are allowed Averaging and en veloping are al
253. m more closely ACQUISITION aroser narooopy SEQUENCE RUN snc shoal CJ GI La Figure 3 2 Front Panel Acquisition Lights Next to the ACQUISITION button are RUN and STOP lights One or the other of these lights is always on telling you whether acquisition is occur ring The Acquire Desc pop up menu in the Waveform major menu also controls acquisition You can specify that acquisition stop after ail the data points are sampled for a single record If you use the averaging or enveloping features you can specify that acquisition stop after enough records have been ac quired to provide a complete average and or envelope NOTE See Averaging and Enveloping on page 3 13 for details of how to use this pop up menu to specify averaging or enveloping modes You can also stop acquisition based on the number of samples or wave forms acquired for a color graded display the number of samples or wave forms acquired for a histogram or the number of hits acquired in mask testing See the sections on Display Persistence page 3 43 Histograms page 3 99 and Mask Testing page 3 119 for more information about these acquisition conditions You use the selectors in the Stop Acquisition On section of the pop up menu to specify that acquisition stop on these various conditions You can specify One Record Average Complete Envelope Complete or Both Avg and Env If you select One Record al waveforms will be reacquired and acquisition w
254. m the user to the sensitivity of the probe offset circuit If offset null and offset gain are not both adjusted correctly measurements taken will be incorrect The absolute voltage values for any cursors dis played in the trace will also be incorrect 3 60 Reference Displaying an Eye Diagram CSA 803A User Manuai Eye Diagrams An eye diagram is typically the display of a random digital data signal versus time with the display triggered by the data clock This section provides general instructions to help you display a constellation or eye diagram on the CSA 803A You will need the following equipment Atleast a single channel sampling head Two SMA cables Astatic protection wrist strap To display an eye diagram perform the following steps C Step 1 Press the UTILITY button touch Initialize in the Utility1 major menu and then touch Initialize in the Verify initialize pop up menu C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A C Step 3 Connecta cable from your data line to channel 1 C Step 4 Connect a cable from your clock to the DIRECT trigger input on the front pane or the PRESCALE trigger input Use the DIRECT input for signals of less than 3 0 GHz otherwise use the PRESCALE input for signals up to 10 GHz Be sure not to exceed the maximum input voltage listed below each of the trigger inputs C Step 5 Press the TRIG
255. may notice that the trace blinks as it is cleared and replaced The Remove Clr pop up menu can also be used to clear the selected trace Figure 3 4 The Clear Trace Pop up Menu 3 5 Acquisition 3 6 Reference Audio Feedback When you select a function on the touch screen a beep indicates that your selection has been noted and is being acted on This beep can be turned on or off To turn the audio feedback on or off use the Instrument Options pop up menu from the Utility major menu Touch the Audio Feedback selector in this pop up menu to turn the beep off or on See Figure 3 5 Audio Feedback o iv Selector S7 46 Ontime 1465 Fh warps Figure 3 5 The instrument Options Pop up Menu CSA 803A User Manual 3 7 Audio Feedback 3 8 Reference Autoset Adjusting an oscilloscope to display a stabie trace of usable size and ampli tude can be a time consuming process The Autoset feature of the CSA 803A can quickly give you a stable meaningful trace display The AUTOSET Button ACQUISITION MUTOSET marocopy SSSusiCe sA Figure 3 6 Front Panel Autoset Button NOTE The sampling head channels must be calibrated for autoset to work properly See Enhanced Accuracy on page 3 49 for more informa tion on sampling head calibration When you press the AUTOSET button located above the sampling heads you tell the CSA 803A to examine the signal and adjust the following con
256. mission For both traces common mode operation appears as though the cable is open at the middle since the two steps meet and are cumulative C Step 10 Turn either knob on the mainframe to adjust the delay for channel 2 This varies the time when channel 2 asserts the TDR step Notice that on the upper trace the second edge moves horizontally and on the lower trace the first edge moves horizontally They are actually the same step seen at different times by the two channels Step 11 Press the WAVEFORM button On the display touch Sam pling Head Fne s Touch 1 and the TDR Polarity selector This causes channel 1 to assert a negative TDR step Touch Exit Reference TDR Notice that the upper channel is asserting a negative TDR step This is equivalent to differential TDR Note that in both traces the step appears as though the cable is shorted at the center of the cable since the two steps meet and cancel to zero volts When the TDR steps on the two channels are opposite one positive and one negative you can now define a trace that represents the true differen tial signal by touching the DefTra icon and touching Mainframe 1 Mainframe 2 Enter Desc When the TDR steps on the two channels are the same polarity both posi tive or negative you can define a trace that represents the true common mode signal by touching the DefTra icon and touching Mainframe 1 Mainframe 2 Enter Desc This exampie has been
257. most portion of the trace You can use horizontal magnification to see the exact data points of a trace record Set horizontal magnification to the maximum and turn off trace vectoring Trace Vectoring is discussed in the Vectored Traces section page 3 217 The display will show each sampled data point of the trace See Figure 3 52 3 109 Horizontal Controls sgppe ne SMI heh BEA PTOI TT NDT Pees 7 3 a SS rrr AS Figure 3 52 Horizontal Magnification with Pan Zoom 3 110 Reference Changing the Horizontal Reference Point CSA 803A User Manual Horizontal Controls When you change the horizontal size of a trace you magnify or compress the horizontal scale Normally the same point of the trace shows at the left edge of the display after the horizontal size is changed The point about which the expansion or contraction of the trace occurs is called the horizon tal reference point You may find that having the horizontal reference point at the left edge of the display is not appropriate for your task For example you have a trace that shows a rising edge of a pulse near the center of the display When you increase the horizontal size of the trace the rising edge moves off the right edge of the display You must move the trace to the left with horizontal position in order to view the rising edge of the pulse at its new size You can change the horizontal reference point to keep the interesting portion
258. n Since the trace is already selected it can also be removed by pressing the SELECT CHAN NEL button on the sampling head The sampling head channel light can have three states off channel not displayed on steady channel displayed only on non selected traces or blinking the selected trace displays this channel The operation of the channel button depends on the light a If the yellow light is off channel not displayed pressing the button creates a trace of that channel ifthe yellow light is on steady channel displayed but not part of the selected trace then pressing the button selects that trace causing the light to blink ifthe yellow light is blinking channel is part of the selected trace pressing the button wili entirely remove alf traces displaying that chan nel L Step 34 Press the sampling head SELECT CHANNEL button beside the blinking light to remove the remaining trace CSA 803A User Manual 2 29 Example 2 Managing Multiple Traces 2 30 Operating Basics Example 3 Defining Complex Traces This example shows how you can create traces that combine signals from more than one channel For this example you will need a CSA 803A with at least one dual channel sampling head installed Also a power divider and two SMA cables of different length will be used 2 ns and 5 ns cables are recommended You may substitute a signal splitting T adapter for the power divider You will also need a stati
259. n fed to the trigger circuits Though the prescal er s divide ratio is fixed it is randomized to prevent locking on a particular bit in a bit stream with a pattern length that is a multiple of eight Signals fed to the PRESCALE connector are AC coupled and can be up to 10 GHz You can set the trigger mode to auto mode which will produce an internal trigger in the absence of other trigger events on the trigger signal Option 10 instruments do not have the prescaier installed CSA 803A User Manual 3 213 Triggering You can assign the knobs to set the trigger level of the selected trace by touching the 7 icon to the left of each graticule Use the Trigger major menu to access ail other trigger controls See Figure 3 104 The selectors in this menu are NOTE Use the trigger icon 7 to assign the knobs to set the trigger level m Source displays a pop up menu that lets you select the signal that the CSA 803A monitors for the trigger event The External Direct source is the DIRECT connector on the CSA 803A front panel The Internal Clock source is synchronized with the CALIBRATOR output on the CSA 803A front panel The External Prescaler source is the PRES CALE connector on the CSA 803A front panel External Prescaler is dimmed if the prescaler option is not installed Figure 3 104 The Trigger Major Menu and Source Pop up Menu m Level assigns the knobs to set the trigger level Touching this selector
260. n on Channel 2 by pressing the select channel button next to the input connector E Step 8 Turn on Channel 1 by pressing the select channel button next to the input connector 3 25 Constellation Diagrams G Step 9 To acquire a constellation diagram you need to sample the data on both channels at a point where it is stable this is not transition ing between states See Figure 3 11 Figure 3 11 Adjusting the Main Position C Step 10 To set the CSA 803A for this condition create a normal YT waveform on each of the two channels Adjust the horizontal size and position to expand a small section of the waveform horizontally and to fill most of the screen vertically The exact settings required to achieve this result will depend on your signal For fast signals you can even set the horizontal size to zero ps div by keying in 0 on the knob pop up keypad Repeat this process for both channels until you have two waveforms that look something like Figure 3 12 3 26 Reference CSA 803A User Manual O O 0 0 Constellation Diagrams at te a a Se i a 45 cHRt ns ipgs div 45 21Btenrs Figure 3 12 How the Expanded Waveforms Should Appear Step 11 Adjust the Main size to 0 ps div You should see two or more distinct voltage levels depending on the signal across the full screen If noi go back to 1 ns div and reposition the four states on the left grati cule edge Step 12
261. n screen menu that always displays the current knob assignment The knob menu aiso lets you display the Keypad menu Knob Resolution The amount of change caused by each click of a knob Major Menu The menu that is displayed at the bottom of the screen alongside the Knob menu One of the several major menus is always displayed Major Menu Button A labeled button above the knobs that determines which major menu is displayed Measurement An automated numeric readout that the CSA 803A provides directly from the displayed trace in real time without operator intervention Measurement Parameter One of several controls that the CSA 803A operator can exercise over the automated measurement process Measurement Statistics The accumulation of a history of individual measurement readouts showing the mean and standard deviation of a selected number of samples Measurement Tracking The process of automatically adjusting the measurement parameters to reflect changes in the trace Mesial The middle point of a range of points As used in the CSA 803A the middle measurement point between proximal and distal points for timing measurements and the intermediate height between baseline and topline for amplitude measurements Glossary Outline Box A visual feedback mechanism of the touch panel Your potential selec tion is always indicated by a box while you have your finger touching the screen Persistence The amount of time a data point
262. nate method is particularly suited to pulse waveforms with ringing or other anom alies Try this method whenever the IEEE method produces unstabie topline and baseline results This choice also affects Automatic Windows see page 3 225 for more information The IEEE method is always used for statistics mode measurements Reference Measurement Mode CSA 803A User Manual Measurements Measurements may be taken in software mode hardware mode or statistics mode In software mode measurements are taken from the digitized trace data record the same data that forms the trace on the display Software mode is the default In hardware mode measurements are taken from the analog signal output from the sampling head before it is digitized and assembled into a trace record The CSA 803A uses special timer circuits to take hardware measure ments The advantage of hardware measurements is that they are per formed faster than software measurements in statistics mode measurements are taken from color graded waveform data and are based on histograms computed at the crossing levels You can use statistical measurements to measure random data such as eye dia grams Statistics mode also provides jitter and noise measurements and can be more accurate for other measurements on waveforms with significant jitter or noise Statistics mode can be selected only in color graded display mode Because the color graded database does not distinguis
263. nd with Trace Vectoring bottom 3 217 Figure 3 107 The Instrument Options Pop up Menu 3 218 Figure 3 108 Vertical Controls 0 0 0 00 0 cece ee ee ees 3 219 Figure 3 109 A Window Trace Display 20 0 e ee cee 3 223 Figure 3 110 The Window Mode Pop up Menu 3 225 Figure 3 4111 An XY Trace ab aint ext nt haw abVan wes crecnanaee ss 3 229 Figure 3 112 The Horizontal Desc Pop up Menu 3 230 xvii List of Figures xviii Contents CSA 803A User Manual List of Tables Table 2 1 Measurement Mode Comparison 0 0 00 2 63 Table 3 1 A Sample Assignment of Colors to Hit Density 3 45 Table 3 2 Time Base Cal Mode Comparison 3 50 Table 3 3 Delay Compensate Comparison 2 0 3 50 Table 3 4 Repetition Encodings c ccs sdeiwaceaehe eae cs ooien8 3 94 Table 3 5 Hardcopy Defaults ccc eee ee eens 3 97 Table 3 6 CCITT G 703 Electrical Standards Masks teen 3 133 Table 3 7 ANSI SONET CCITT SDH Optical Standards Masks 3 134 Table 3 8 ANSI 71 102 Electrical Standard Masks 3 135 Table 3 9 Miscellaneous Standards Masks 0205 3 135 Table 3 10 Measurements 0 00 c cence eres 3 138 Table 3 11 Measurement Mode Comparison 0 0 200 3 145 Table 3 12 Measurement Parameters 0 0 0 0 ce cee eens 3 151 Table 3 13 Trace Functions 1
264. ng m Stored Traces specify a previously stored trace a Syntax includes parentheses Back Space which can be used for successive entries and Enter Desc which enters your completed expression removes the pop up menu and creates the trace Cancel removes the pop up without defining a trace Now you can enter a difference expression M1 M2 if you are using differ ent channels you will use different numbers This example uses M1 for the channel the short cable is connected to C Step 10 Touch 1 under Mainframe Channels in the numeric keypad area 2 under Mainframe Channels and Enter Desc all in the pop up menu 2 33 Example 3 Defining Complex Traces The difference trace is created Notice that on the sampling heads both of the yellow lights for the source channels are blinking indicating that both channels are represented in the selected trace faethe al ee ENET NEN prea Vertical Description Beceem een aw an nm a a anann a a ARN NEE SOON RN Samay anenee ev Mainframe Channels Figure 2 22 The DefTra Pop Up Menu 2 34 Operating Basics Vertical Adjustment of Complex Traces Example 3 Defining Complex Traces You can change the vertical size and offset of only one input channel at a time even if the selected trace represents several inputs C Step 11 Make the selected trace the single source trace from the short cable Select this trace by touching it Check the Vertic
265. ng moni tored by the trigger circuits passes through a specified voltage eve in the specified direction the trigger slope Until a trigger event takes place a newly defined trace will not appear on the display If triggering of an acquired trace stops the last trace record is left frozen on the display The trigger status is shown to the left of the graticule as either trig d or Inot trig d The trigger source can be the internal clock or a signa that you apply to one of the trigger input connectors on the CSA 803A front panel You can con nect the signal being sampled to the trigger input connectors using a signal splitter or power divider so that the sampled signal is also the trigger signal Whatever signal you use as the trigger source it should be synchronized with the signal you are sampling and displaying For Direct input you can only view the trigger event if it preceded the observed event by at least 21 ns NOTE When you use an external trigger source the CSA 803A may not be supplied with triggers To restore operation supply a trigger signal to one of the trigger inputs or select the Auto mode External triggers can be connected to either the DIRECT or PRESCALE connectors on the CSA 803A front panel Signals connected to the DIRECT connector are fed directly to the trigger circuitry The signal is DC coupled and can be up to 3 0 GHz Signals connected to the PRESCALE connector are divided by eight and the
266. ng the Reference You will use this measurement value as a reference value The Compare amp Value References pop up menu allows you to save this value and cause all meas urements to be displayed as a difference from this vaiue See Figure 2 47 just References Figure 2 47 The Compare amp References Pop Up Menu C Step 13 Touch Compare amp References and then touch Save Current Meas Values as References You will see that this reference value for the cross measurement is now very close to the cross measurement value in the major menu area they may not match exactly because of noise or horizontal jitter The Cross selector in the major menu area displays the measurement parameters pop up menu The Cross Ref selector in the Compare amp Refer ences pop up menu assigns the knobs to adjust the reference value this is useful when you want to establish your own standard reference value The Compare selector in the Compare amp References pop up menu changes the entire measurement system This makes the measurement system display the measured deviation from the references rather than the direct measurement C Step 14 Touch the Compare selector to set compare on and touch the Exit selector to remove the pop up menu The Cross measurement selector in the major menu area has changed to ACross and the value being displayed is at or near zero The zero value shows that this cabie deviates very little from its own signal prop
267. nger is the second cable The Graticules 3 3 selector on the Waveform major menu lets you choose feet meters or Inches inches for the horizontal axis See Figure 2 46 C Step 10 Press the WAVEFORM button and touch the Graticules selector Figure 2 46 The Graticules Pop Up Menu 2 76 Operating Basics CSA 803A User Manual Example 7 Taking Comparison Measurements Using a Reference Trace The pop up menu shows an X Units section near the bottom You can select seconds meters feet or inches In addition the Propagation Velocity selector can be used to assign the knobs to let you indicate the signal speed of your cable The default 0 7 indicates that the horizontal axis labels if inches feet or meters will be based on a cable that passes signals at 0 7 times the speed of a cable having free air insulation O Step 11 Touch Inches Feet or Meters in the pop up menu If you know that the propagation velocity of your cable differs from the default touch the Propagation Velocity selector and adjust this parameter If you don t know the velocity or are using Tektronix polyethylene dielectric SMA cabies accept the 0 7 default C Step 12 Press the MEASURE button to redisplay the Cross measure ment The measurement readout is in the units of distance that you selected Also the horizontal axis is labeled in the units chosen 2 77 Example 7 Taking Comparison Measurements Using a Reference Trace Usi
268. ning Window FFT Magnitude Displayed Using Hamming Window GPIB Rear Panel Connector and Lights The GPIB RS232C Pop up Menu 65 Graticule with Trace 55 Aa een eon teeke cae sued Dual Graticules with Multiple Traces The Graticules Pop up Menu 02 2200s Printer Connectors on Rear Panel The Hardcopy Pop up Menu 6 i gicoe scsi eawtiias eee Front Panel Hardcopy Button 005 A Histogram Displayed on an Eye Diagram The Persist Histograms Pop up Menu Using Stop N WMS 24s C a lho Ses sera daly FA eean Histogram Readout Appears Below the Trace ee enny ranyoy EAS AAAn Horizontal Magnification with Pan Zoom The Horizontal Desc Pop up Menu The Initialize Verification Pop up Menu Labels Displayed with Active Traces The Labeling Pop up Menu 00200 Mask Testing on an Eye Diagram The Standard Masks Pop up Menu Pages 2 and 3 of the CCITT Electrical Standards The Mask Testing Pop up Menu 004 Editing a Mask od acre es act Faved dhe le aun cd oa aaa cee 3 46 3 49 3 51 3 55 3 57 3 62 3 66 3 67 3 68 3 70 3 72 3 73 3 75 3 75 3 76 3 77 3 77 3 78 3 79 3 80 3 83 3 84 3 85 3 89 3 91 3 96 3 99 XV List of Figures Figure 3 62 Figure 3 63 Figure 3 64
269. ntal Desc pop up menu in the Waveform major menu and is determined by the time base and record length A trace record of N points in the time domain corresponds to a record of the same number of points in the frequency domain However for any reai signal the frequency domain data will be symmetrical about DC so only the positive part of the spectrum is displayed Of the displayed points of the FFT trace the N 2 even numbered points are the frequency lines computed by the FFT the N 2 odd numbered points are added by linear interpolation The maximum frequency that can be determined by a Fast Fourier Trans form is the Nyquist frequency which is equal to one half the effective sample rate In fact the maximum frequency displayed by the CSA 803A Finay is slightly lower than the Nyquist frequency it is equal to the Nyquist frequency minus the frequency interval oF the interval between frequency lines The frequency range displayed is from DC 0 Hz to Finay The frequency interval SF is equal to the Nyquist frequency the maximum possible recognizable frequency divided by the number of frequency lines in the FFT display half the record length of the time domain trace Since the Nyquist frequency is half the effective sample rate this works out to the effective sample rate divided by the record length 7 effective sample rate _ _ sample interval effective sample rate ae record length effective sample rat
270. o histogram displays The range for refresh rate is 5 s to 180 s To change the refresh rate display the Per sist Histograms pop up menu and touch Refresh Rate Both of the knobs are now assigned to control the refresh rate You can also set the refresh rate to 0 using the keypad pop up menu which means the display is never updated The color graded database is not affected by the refresh rate only the display is so setting the refresh rate to 0 may speed some computations such as measurements lf any displayed waveform has a record length longer than 512 points when Color Grading is selected the record length is set to 512 points anda message is displayed informing you of the change in record length interpreting the Color Graded Display Colors in the color graded display are based on the number of hits that have fallen in a bin with a bin assigned to each pixel of the display A bin can represent a maximum of 65 535 hits In a single graticule dispiay the bins are arranged in a 512 horizontal by 256 vertical matrix In a dual graticule display there are 512 horizontal by 128 vertical bins on each graticule There are three algorithms used to assign colors to the display The algo rithm used depends on the maximum number of hits for any pixel in the display These algorithms are detailed in Appendix D Aigorithms An exam pie of the assignment of colors is shown in the table below Max in the table represents the max
271. ode is selected from the Persist Histograms pop up menu To display the Persist Histograms menu press the DISPLAY MODES button and then touch Persist Histograms See Figure 3 20 Figure 3 20 The Persist Histograms Pop up Menu CSA 803A User Manual 3 43 Display Persistence Setting the There are four persistence modes in the Persist Histograms pop up menu Persistence Mode To select the mode touch the appropriate selector Normal In normal mode each record replaces its predecessor record by erasing it from the screen Variable In variable persistence mode the CSA 803A accumulates waveform data on the screen for a user specified period and then automatically removes them from the screen after the time has expired or aged The duration over which the waveform is displayed on the screen before the data is removed is user selectable The range for persistence is 200 ms to 20 s To set the duration select Persist Time and use the knobs or the keypad pop up menu to set the time Variable persistence mode cannot be selected when histograms are dis played or mask testing is occurring Histograms and mask testing can be displayed only in infinite persistence and color grading modes If any dis played waveform has a record length longer than 512 points when Variable Persistence is selected the record length is set to 512 points and a mes sage is displayed informing you of the change in record length Infinite In infin
272. of hits for a given pixel Color grading adds a third dimension to the persistence display and allows accumulating data in a statistical database for later analysis with histograms or masks To turn on color grading touch the Persist Histo grams selector touch the Color Grading selector in the pop up menu and touch the Exit selector to remove the menu For more information on color grading see Setting the Persistence Mode on page 3 44 O Step 11 After enabling color grading measure eye pattern characteris tics such as risetime jitter and noise in the Statistical Measurement Mode To turn on Statistical measurement press the MEASURE button touch the Measurements selector touch the Statistics Mode selector and then touch the desired measurement for example risetime For more information on statistics mode see Measurement on page 3 137 3 63 Eye Diagrams ERE A NN TT HHH EE AEA AAAI HHH tt SSS MMH a he s rH 3 64 Reference CSA 803A User Manual Fast Fourier Transforms You can use the Fast Fourier Transform FFT capability of the CSA 803A to obtain a frequency domain display of a trace You can display both the magnitude and the phase of the frequency components of the signal using a linear or decibel vertical scale You can perform Fast Fourier Transforms on any arbitrary trace The record length of the trace must be a power of two up to a maximum of 4096 points Because the CSA 803A performs FFT calculations
273. of the first graticule division C Step 4 Terminate the cable using a 50 Q terminator Observe that the impedance change moves the entire trace vertically on the display C Step 5 Remove the 50 Q terminator C Step 6 Turn baseline correction on L Step 7 Replace the 50 Q terminator on the cable Observe that this time the baseline of the signal has not moved vertically on the display instead the vertical axis coordinates have adjusted to the new trace values being displayed 3 17 Baseline Correction 3 18 Reference CSA 803A User Manual Calibrator The CALIBRATOR output connector provides a known signal output for your use in calibrating sampling heads This connector is found at the bottom right of the front panel See Figure 3 9 ood a oh J t awl L The CALIBRATOR and INTERNAL CLOCK Outputs Figure 3 9 Location of the CALIBRATOR and INTERNAL CLOCK Outputs The signal from the calibrator output is a fast risetime 250 mV square wave with a period of approximately 10 us The internal clock trigger source is synchronized with the calibrator output and provides a trigger event approximately 21 ns prior to the rising edge of the calibrator signal This synchronized trigger signal is available at the INTERNAL CLOCK connector located below the sampling heads To see the calibrator signal on the screen follow these steps g Step 1 initialize the instrument press the UTILITY button touch Initial
274. oints have been sampled The following safety information is provided for your protection and to pre vent damage to the CSA 803A This safety information applies to all opera tors and service personnel See Appendix C for additional safety information Terms in Manuals CAUTION statements identify conditions or practices that could result in damage to the equipment or other property WARNING statements identify conditions or practices that could result in personal injury or loss of life Terms on Equipment CAUTION indicates a personal injury hazard not immediately accessible as one reads the marking or a hazard to property including the equipment itself DANGER indicates a personal injury hazard immediately accessible as one reads the marking Symbols in Manuals Static Sensitive Devices Introduction Symbols on Equipment 4 A DANGER Protective ATTENTION High Voltage ground earth Refer to terminal manual Power Source This product is intended to operate from a power source that will not apply more than 250 Vays between the supply conductors or between either supply conductor and ground Grounding the CSA 803A The CSA 803A is grounded through the power cord To avoid electric shock plug the power cord into a properly wired receptacie where earth ground has been verified by a qualified service person Do this before making connections to the input or output terminais of the CSA 803A Without the prote
275. ollowing settings are not affected when you initialize Stored traces and stored settings Sampling head calibration values e Time and Date w The following GPIB parameters Address Mode and Terminator u The following RS 232 C parameters Baud Rate Echo Stop Bits Parity Flagging Delay and EOL String w Hardcopy parameters CSA 803A User Manual 3 113 Initialization Initializing and Erasing Nonvolatile RAM 3 114 You can erase all information stored in nonvolatile RAM by holding down both the WAVEFORM and TRIGGER major menu buttons when you turn on the CSA 803A Release the buttons when the lights next to the major menu buttons stop flickering When the power on sequence is complete the message Teksecure Erase Memory Status Erased Instrument ID on time and number of power ups retained will appear on the display When nonvolatile RAM is erased in this manner the CSA 803A writes the hexadecimal value DEAD over all nonvolatile RAM locations for settings traces and saved trace descriptions The following information is not lost when nonvolatile RAM is erased Serial number of the CSA 803A Accumulated time the CSA 803A has been on Number of times the CSA 803A has been powered on Factory calibration constants which are established at the factory and cannot be changed by the user or by the CSA 803A Enhanced Accuracy calibration constants which are periodically calcu lated and updated Time and Date
276. on a complete trace record you should use the shortest record length that provides adequate resolution FFT traces update slowly at long record lengths The CSA 803A offers a choice of six FFT windowing functions which modify the time domain data to minimize leakage of energy across frequency components The three automated measurements spectral frequency speciral magnitude and total harmonic distortion are intended for FFT traces See Measure ments on page 3 137 for more information on these measurements You can also use the cursors to take magnitude and phase measurements on frequency domain traces 3 65 Fast Fourier Transforms Defining an FFT You can define an FFT display of a trace using the DefTra pop up menu or Trace you can use the FF Tmag and FFTpha icons Defining an FFT Display Using the DefTra Pop up Menu You can define a trace that displays the FFT magnitude or FFT phase using the DefTra pop up men which is displayed when you select the DefTra icon The FFTmag and FFTphase selectors can be used to define a display of the magnitude or the phase of the frequency spectrum of a trace See Figure 3 27 The part of the trace description that is within the FFTmag or FFT phase function may be any arbitrary trace Mainframe Channeis FFT mag and FFT phase Selectors Figure 3 27 The DefTra Pop Up Menu 3 66 Reference CSA 803A User Manual Fast Fourier Transforms Defining an FFT D
277. on in the MENUS column touch Initialize in the major menu and touch Initialize in the verification pop up menu C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A C Step 3 Connect the CALIBRATOR output to any sampling head input w aol w awd L Figure 2 33 Connections for Example 5 C Step 4 Press the SELECT CHANNEL button on the sampling head channel you have connected to the calibrator signal C Step 5 Press the TRIGGER button and touch Source in the major menu Select Internal Clock in the pop up menu and touch Exit to remove the pop up menu CSA 803A User Manual 2 53 Example 5 Taking Automated Measurements 2 54 C Step 6 Press the AUTOSET button You should have a stable display of the calibrator signal showing several cycles It is important that all of the signal is on the display and that there are no places where the trace extends above or below the graticule area NOTE Get a stable signal display before using the automated measure ment system Operating Basics Specifying Measurements CSA 803A User Manual Example 5 Taking Automated Measurements The automated measurement system lets you specify a set of measure ments for every trace on the display The readouts of these measurements are continually updated to track changes in the signal Up to twenty eight different measurements are availab
278. on is unaltered Figure 3 102 The Remove Selector in the Remove Clr Pop Up Menu Removing Traces Using the Sampling Head Channel Button You can use the Select Channel button on the sampling head to remove all traces displaying that channel as part of their trace expression When a sampling head channel is incorporated as part of the selected trace the yellow channel light on the sampling head is on and blinking If you press the channel button on the sampling head when the light is blinking a traces displaying that channel are removed Removing Traces Using the Store Recall Delete Trace Selector You can delete displayed traces by using the Delete Traces pop up menu in the Store Recall major menu This pop up menu may also be used to delete displayed traces 3 210 Reference Trace Definition and Management In the Delete Traces pop up menu touch the selectors for the displayed and stored traces you want to delete The traces are not deleted until you touch the Delete Selected Traces selector You may select several traces to be deleted before touching the Delete Selected Traces selector As you select traces to delete their selectors highlight to tell you they will be de leted If you touch a trace selector by accident touch it again to remove the highlighting If you want to delete all the displayed and stored traces touch the All Traces selector CSA 803A User Manual 3 211 Trace Definition and Management Trace Sc
279. on medium you can convert their dielectric constant to a propagation velocity using the following equation 1 Prop velocity gt meeer Vdielectric constant The horizontal axis is now calibrated in your chosen units of measurement 3 194 Reference CSA 803A User Manual TDR NOTE Measurements and cursor readouts are always expressed in the same units as the graticule axes To set the vertical axis to rho you need to specify the amplitude in volts of the incident step that the sampling head sends through the cable Touching the Reference Amplitude selector assigns both knobs to this parameter For the SD 24 this step amplitude is 250 mV This amplitude is also the default setting of this parameter so you don t need to change this parameter when using the SD 24 For the SD 20 the step amplitude depends on the external signal source used Note that when using the TDR Preset function the vertical axis scaling is automatically set to Rho 0O Step 8 Touch Exit to remove the pop up menu and view the trace and graticule 3 195 TDR Example Differential and Common Mode TDR 3 196 The CSA 803A can perform differential and common mode TDR measure ments with the SD 24 sampling head As described earlier the sampling head has two sampling input channels and two independent step genera tors The step generator output for each channel is selectable for positive or negative polarity and amplitude This examp
280. on the CSA 803A rear panel see Figure 3 76 The CSA 803A is configured as data communications equipment DCE and the computer must be configured as data terminal equipment DTE RS 232 C Connector Figure 3 76 Location of RS 232 C Connector CSA 803A User Manual 3 165 RS 232 C Parameters Setting RS 232 C Communication between the CSA 803A and the attached computer can Parameters occur only if the two are configured in a compatible manner Use the GPIB RS232C pop up menu in the Utility major menu to set the RS 232 C parameters directly before you attempt to communicate with the attached computer See Figure 3 77 Figure 3 77 The GPIB RS232C Pop up Menu The following list describes each selector in the RS232C Parameters sec tion of this pop up menu Baud Rate assigns the knobs to adjust baud rate and delay You can set the baud rate to 110 150 300 600 1200 2400 2400 4800 9600 or 19 200 You should set the baud rate to match the computer you are using NOTE The RS 232 C parameters are not changed when you initialize the CSA 803A Echo lets you set echo to ON or OFF If you observe two identical characters transmitted when you expect only one echo is on when it shouldn t be If you see no character transmitted when one was ex pected echo might be set to off inappropriately 3 166 Reference RS 232 C Parameters Stop Bits lets you select among 1 1 5 or 2 stop
281. one trace or maintain enough vertical separation be tween traces so they don t overlap Also histograms can be displayed caiculated after waveforms have been accumulated in color graded mode even if acquisition has been stopped whereas they cannot in infinite persistence mode By using dual graticules you can acquire color graded information on two traces simultaneously Display one trace on each graticule and set up a histogram for each trace Both histograms are acquired but only the histo gram for the selected axis is displayed Since the color graded database is used the second histogram can be seen later 3 101 Histograms Hi stogram Controis The histogram display can be affected by several controls You can specify which part of the selected trace is used to calculate the histogram You can stop acquisition based on the number of waveforms acquired or the number of histogram samples acquired You can set how often the histogram display is updated with new data and you can set scaling to logarithmic or linear AH the histogram controls are located in the Persist Histograms pop up menu Changing the Size of the Histogram Box To change the section of the selected trace used for the histogram touch either Vertical Limits or Horizontal Limits Touching the Vertical Limits selector assigns the top knob to Upper Limit and the bottom knob to Lower Limit Touching Horizontal Limits assigns the top knob to Left Limit and the botom
282. onnection is coshai div ewhesreadesary EEI EEPE 3 79 Setting GPIB Parameters 2 ccc seen ee acne nn eennee 3 80 GPAUCUICS ise ead eed costa teens eee ener sneaks beams 3 83 Managing Graticules and Traces 000 eee secre 3 86 Changing Axis UnHS aanassrsnunnranenrnveannasnn gt 3 87 Vertical Axis Units 2 cca new ous ociven Weaene es eee es dg ees 3 87 Horizontal Axis UniS wii iota esa uel tues awe aceess 3 88 PIStOCOBY ot oo eed See t unea tos ean Ge nhs keane ewedte eee 3 89 Installing the Printer lt 2 csc20 e6 cescece cites eas eile oe aes 3 89 Hardcopy Parameters 0 0 cece eee eee eee eens 3 91 Printer Selections 5540 v0y lt un aoe sve tale eee eu aeeh ws 3 91 COON WAP Liccsinntak an bax tae Oe Gea OW mae aE eae 3 93 ocreen Format we scctenss ered dou ccs ees sate ce eG na 3 93 LS CUOM va yn GG e assent wea E Ae COR ea EOE Eos 3 93 Data Format siesid sou ia ea E oo wudnt ae Roe A EEES 3 94 Qutput Pome aaeada cana we ein peek nie ba ae ANN utes 3 95 Making a Hardcopy 2 6 2 6 4esdne ieee ise eee dente aww ees 3 96 Terminating A Hardcopy In Progress 00seeauee 3 97 Hardcopy Defaults snsnrenserssnserenrrrsrrnusrones 3 97 PUSIOUTAMNS ossos coe eases naa e d e ea e eee ETDAN EN 3 99 Displaying a Histogram sasasssesusnanssurevusansna 3 101 Histogram Controls esessessssnnsrsrssnnsensrrneus 3 102 Changing the Size of the Histogram Box 005 3 102 Limiting Acqui
283. op Gain Calibration in Vectored Trace Mode Calibrating Blowby Compensation Manually To calibrate blowby compensation manually first establish a display of the calibrator signal on the sampling head channel you want to calibrate Adjust the vertical size to 50 mV div and the horizontal size to 500 ps div Center the rising edge of the calibrator trace on the graticule Adjust the calibration value to the display that gives the flattest horizontal trace segments Calibrating Offset Manually To calibrate offset manually first attach a 50 Q terminator to the sampling head channel you want to calibrate Establish a trace showing this channel with a vertical size of 50 mV div For the most accurate results you should provide the trigger for this calibration that will be used to perform measure ment and testing of the input signal If possible you should also set the trigger hold off to the same value that will be used in test If you do not provide a trigger the CSA 803A will automatically use the internal clock as a trigger At the Acquire Description pop up menu selected at the Waveform major menu set Average N to On Touch the vertical icon and the Vert Offset knob label selector to show the Numeric Keypad pop up menu On the 3 57 Enhanced Accuracy 3 58 pop up menu touch 0 and Enter This sets the vertical offset to zero posi tioning 0 V at the center height of the graticule This calibration does not apply to the S
284. op of the pop up menu The Back Space selector lets you correct errors as you type When your trace expression is complete touch the Enter Desc selector to remove the pop up menu and create the new trace For example to enter the expression Log M1 M2 touch the following selectors in sequence Log 1 2 Enter Desc Another example of a trace expression M1 2 Smooth ST0O1 5 is en tered as 1 2 Smooth Stored Traces STO1 5 Enter Desc The selectors presented in the DefTra pop up menu are grouped into the following categories a Channel Selectors let you specify a sampling head channel The CSA 803A presents only those channel numbers where a sampling head is installed Numeric Keypad lets you enter a numeric value as part of your trace expression or one of the four arithmetic operators and a Trace Functions let you specify a function which are listed on the next page This area of the menu is shared with the stored traces selec tors described below If the Trace Functions selector is highlighted the trace function selectors are shown Touch the Trace Functions selector to highlight it if the stored traces list is shown NOTE Trace Functions and Stored Traces can both be included in a single trace expression 3 204 Reference Trace Definition and Management Vertical Descristian i E PEES ner TR ba oe eid i F are TEA N Trace Expression gag Main
285. op up menu This sequence pressing the UTILITY button and then touching the Initialize selector will always set the CSA 803A to a default state C Step 3 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A CSA 803A User Manual 2 5 Example 1 Displaying a Trace Connecting Cables To view the calibrator signal you must connect a cable from the CALIBRA TOR output to any sampling head input connector Cj Step 4 Connect an SMA cable from the CALIBRATOR output to either input connector of any installed sampling head see Figures 2 3 and 2 4 Read the Operator Overview section for information about SMA compatible connectors Figure 2 3 Cable from the CALIBRATOR Output to a Sampling Head input Beside each sampling head input is a small SELECT CHANNEL button Pressing it is a quick way to display that channel The resulting yellow light near the button teils you that the channel is being displayed 2 6 Operating Basics Example 1 Displaying a Trace APC 3 5 input Connectors TDR SAMPLING HEAD Figure 2 4 Sampling Head Control Panel SD 24 shown 0O Step 5 Press the SELECT CHANNEL button nearest the SAPR head input you have connected to the calibrator The yellow light on the sampling head blinks indicating that the channel is being displayed ate You don t see a trace on the display because the trace is not triggered The trig
286. ora the knob fabeis to see the Keypad Menu which description of the various major menus fets you enter a numeric value for any knob conitrolied parameter See page 1 15 CSA 803A User Manual 1 13 Ata Glance Icons lt gt Touch the horizontal icon to assign the knobs to adjust the trace horizontal size and position See page 3 167 at Def Tra Touch the Define Trace icon to display a pop up menu that lets you define a new trace to be displayed See page 3 203 FFTmag Touch this icon to display the magnitude of the frequency spectrum of the selected trace This icon is then replaced by FFTpha See page 3 65 Window Touch the window icon to create a new trace that represents an enlarged portion of another trace See page 3 223 Cursors Touch the cursors icon to display bar or dot cursors for 5 Afia Sag measurements of trace re o iy values See page 3 29 Normal Li cnrarnetanan en atatenatatantatn fame A Pe x Touch the trigger icon to assign Touch the vertical icon to i the knobs to adjust the trigger t assign the knobs to adjust Gna A pilin level if the instrument is not the trace vertical size and g hatis diep d triggered not appears above position See page 3 219 Peni Matse Clepiayed the word trig d See page 3 213 1 14 Getting Started Knobs Knob Menu and Keypad Menu Ata Glance if you touch the wrong knob label by accident the top two selector
287. ose Interface Bus An interface that allows remote computer control of and data capture from a CSA 803A Graticule The grid where traces are displayed Hardcopy A paper print or plot of the display Hardware Measurement An automated measurement that is captured by special circuitry that monitors signals directly as opposed to software measurements that are derived from acquired trace samples Highlighted Trace The selected trace in a single graticule or dual graticule display Also in a dual graticule display the last selected trace on the non active graticu ie the graticule without icons Horizontal Reference Point The point about which the trace is expanded or contracted when hori zontal size adjustments are made The horizonta reference point re mains anchored as the rest of the trace grows or shrinks around it Glossary CSA 803A User Manual Glossary Icon A marker on the edge of the graticule that performs a specific function when touched Initialize Setting the CSA 803A to a completely known default condition Internal Clock A trigger source that is synchronized with the Calibrator signal Keypad Menu A pop up menu that controls knob resolution and lets you enter specific numeric values for any control to which a knob is assigned Knob One of the two large rotary controls to the right of the CSA 803A screen Knob Assignment The value that a knob will adjust at a given time Knob Menu The o
288. osition of the trace which is set using the knobs After the first point is digitized the CSA 803A waits for another trigger event before sampling and digitizing the second point of the trace record For the second point the waiting time between the trigger event and the sampling and digitizing of the point is increased by the sample interval Sampie Interval First Sampled and Digitized Point Trigger Event on Trigger Signat Horizontal Position Figure 3 1 Acquisition of a Trace The acquisition process continues until all the points in the trace are sam pled and digitized Points are acquired in order from left to right and each point is sampled from a separate trigger event When all the points in the trace record have been sampled and digitized the trace is displayed Note that for very siow trigger rates with traces that do not involve math functions or operations a partial trace will be displayed even before all data points are accumulated Acquisition Determining the Sample Interval 3 2 A trace remains on the display until it is replaced by a more recent acquisi tion or until you clear the trace The process of clearing traces is described on page 3 5 You can set the number of points in a trace record called the record length to be 512 1024 2048 4096 or 5120 points Setting the record length is described in more detail on page 3 163 The sample interval is the time difference represented be
289. oss Cross and Slope negative 4 If Slope positive search for the third left most mesial crossing and continue the search to find the next upper signal noise ratio level cross ing to the right If Slope negative use the next lower signal noise ratio level crossing to the right The horizontal coordinate of this crossing is Cross 5 Calculate the period Period Cross Cross Linear interpolation between vertical points and between time intervals is necessary to determine the crossing time when the mesial value does not correspond to acquired data Phase 1 On the selected waveform search the measurement zone for the teft most mesial crossing The horizontal position is Crossge 2 Onthe reference waveform search the measurement zone for the left most mesial crossing of the same slope The horizontal position is CrosSyef D 18 Appendices Appendix D Algorithms 3 Calculate the skew Skew CrO8Sjep CrOSS sei Linear interpolation between vertical points and between time intervals is necessary to determine the crossing time when the mesial value does not correspond to acquired data 4 Calculate the period value of the selected waveform Perform a Period measurement 5 Calculate the phase shift 2 Skew Phase 30 x Pood mod 360 lf the measurement of either Period or Skew results in an error the Phase measurement will show error Prop Delay 1 On the selected trace search the
290. out the protective ground connection all parts of the CSA 803A are potential shock hazards This includes knobs and controls that may appear to be insulators Use the Proper Fuse To avoid fire hazard use only the fuse specified in the parts list for your product and which is identical in type voltage rating and current rating Do Not Operate in Explosive Atmospheres The CSA 803A provides no explosion protection from static discharges or arcing components Do not operate the CSA 803A in an atmosphere of explosive gasses Do Not Remove Covers or Panels To avoid personal injury do not operate the CSA 803A without the panels or covers Operating the instrument without the covers in place may cause overheating and harm the instrument C 2 Appendices Electrical Connections CSA 803A User Manual Appendix C Safety SMA Compatible and Other Precision Connectors You must attach cables to SMA compatible connectors carefully to prevent damage to the cable or the instrument connector Do not overtighten SMA compatible connectors When attaching a cable to or removing a cable from an SMA compatible connector do not turn the cable turn only the nut Align the two connectors carefully and engage the connector nut over the exposed threads on the other connector Use only finger pressure to make this initial connection Then use a torque wrench only to tighten the connection to the range of 7 10 Ib in 79 112 N cm
291. owerupe Touch this selector to turn clock See page 3 201 7 on or off time and date 1 26 Getting Started At a Glance Enhanced Accuracy Major Menu Calibrate blowby compensation of the sampling heads that use this calibration See page 3 49 Calibrate gain of sampling heads See page 3 49 na Calibration m RYT Pie Lace hain nme j j j j j j i j j TRIGGER MEASURE pes sitye i j i Henu DISPLAY MODES STORE RECALL UTHITY This pop up menu controls the automatic self calibration system This pop up menu provides assistance in making ail See page 3 49 calibrations of a sampling head quickly See page 3 49 CSA 803A User Manual 1 27 A 3 i H At a Glance Use this pop up menu to compensate for minor timing variations between sampling heads See page 3 49 Relay R dustment Calibrate offset of sampling heads See page 3 49 i H paranana EE TRIGGER MEASURE DISPLAY MODES STORE RECALL UTILITY Use this selector to access the Utility2 major menu See page 1 29 Setieortast Channel p Seiected Channel ri 3 Calibrate the TDR amplitude of those sampling heads that support TDR See page 3 49 1 28 Getting Started Utility2 Major Menu WAVEFORM TRIGGER MEASURE DISP
292. own The Sampling Head Fne s Pop up Menu The Store Setting Pop up Menu The Recail Setting Pop up Menu The Delete Setting Pop up Menu Front Panel SEQUENCE SETTING Button The Store Trace Pop up Menu The Recall Trace Pop up Menu The Delete Trace Pop up Menu The Identify Pop up Menu Step Generator Simplified Schematic Diagram Step Generator with a Shorted Output Step Generation with a 50 Q Load Step Generation with a 50 Q Load Connections for Example TDR Step and Reflection The Graticules Pop up Menu Single Channel TDR Channels 1 and 2 TDR Ensuring Pulses Arrive at the Reference Plane atthe pean ee eee oe ee ee a srtrewvanrveekana es een oe ee ee sos ee Pe a Cd ee ee Pe 2 Ce nunsuisus gt suoasopa e Ce ee ee re ee ete ena ee oe oh eee Pe ee ee evano nsasaanr o gt eo cee ee oe et eo es eee tee RRR HE Cr a eo The Instrument Options Pop up Menu Deere eee ern eee ere er eo ee ew ee ee Contents CSA 803A User Manual List of Figures Figure 3 102 The Remove Selector in the Remove Clr Pop Up MON ii Sirens Aracd Hee cone eh ee eames wees dale ewes 3 210 Figure 3 103 The Instrument Options Pop up Menu 3 212 Figure 3 104 The Trigger Major Menu and Source Pop up Menu 3 214 Figure 3 105 The Trigger Major Menu and the Trigger Holdoff PODAUD MEME 4 22506 ue vet poised ys eit teed eens ueosanede 3 216 Figure 3 106 identical 512 Point Traces without Trace Vectoring top a
293. p 1 Initialize the CSA 803A press the UTILITY button in the MENUS column touch Initialize in the major menu and touch Initialize in the verification pop up menu C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A C Step 3 Connect the short cable from the CALIBRATOR output of the CSA 803A to a sampling head input t w l m md a L Figure 2 45 Connections for Example 7 C Step 4 Press the TRIGGER button and touch Source and Internal Clock Touch Exit to remove the pop up menu Cj Step 5 Press the SELECT CHANNEL button on the sampling head input that the calibrator signal is connected to C Step 6 Turn the top knob to the left to set the horizontal scale to 10 ns div You will see the calibrator signal on the display 2 75 Example 7 Taking Comparison Measurements Using a Reference Trace You will measure the difference in propagation time down the two cables which are different lengths The cross measurement which shows the time delay from the trigger to the rising edge of a signal will be the basis of your comparison C Step 7 Press the MEASURE button C Step 8 Touch Measurements and Hardware Mode LC Step 9 Touch Cross and touch Exit if you want to observe the trace Setting X Axis Units The measurement will be more useful to you if it is expressed in distance to Meters Feet or rather than time how much lo
294. p 13 Press the SELECT CHANNEL button of the sampling head channel to which you have connected the INTERNAL CLOCK output Cj Step 14 If both traces are on a single graticule move one to the other graticule by touching either Lower Graticule or Upper Graticule and Move Trace to Other Graticule You should now see a trace on each graticule You will use split dot cursors to measure the delay time between these traces Cl Step 15 Touch either trace on which you want to place a cursor In this case since there are only two traces on the dispiay this step is already done Cj Step 16 Touch the Cursors icon and the Cursor Type selector Touch the Split Dots selector Figure 2 44 The Cursor Type Pop Up Menu in Split Dots Mode 2 71 Example 6 Taking Delay Measurements Using Cursors When you first select split dots cursors both dots are on the selected trace The Cursor Type pop up menu remains on the display until you select the trace you want to move the other cursor to See Figure 2 44 Beneath the selectors that allow cursor choice a second set of selectors lists ail of the traces currently on the display The highlighted selector always shows which trace the second cursor is assigned to NOTE Each trace selector for the second cursor shows the trace descrip tion Initially both dots are placed on the selected trace so the highlighted selec tor shows the selected trace Touching the only other trace selector in t
295. pabie of performing single ended TDR when used with an external signal generator This discussion pertains mainly to the SD 24 TDR Sampling Head The step generator circuitry consists fundamentally of an adjustable current source and a diode switch Initially before the step the diode switch is biased to conduct current to the output When the diode switch opens the step occurs Figure 3 89 a simplified diagram shows the switch and the current source Acquisition Point 50 rh 10 MA Figure 3 89 Step Generator Simplified Schematic Diagram Because of the architecture of the step generator the output voltage of the step depends on the DC resistance to ground of the device under test The following sections describe the operation with a short circuit an open circuit and a 50 Q load 3 189 TDR 3 190 Operation Into a Short Circuit Initially the diode switch is conducting 10 mA Since the step generator output is initially shorted the resistance to ground is 0 Q and the output voltage is 0 V When the diode switch opens reverse biased apparent resistance to ground at the acquisition point and at the channel connector is 25 Q because the internal termination resistance is 50 Q and the connector impedance is 50 Q The voltage at the acquisition point rises to 250 mV The transition propagates to the short in the device under test and is nega tively reflected back to the acquisition point cancelling the
296. paration When you use the icon to offset any trace the Chan Sel selector in the lower right corner of the screen can be used to select which channel you want to size or offset Touch the Chan Sel selector until it shows the channel you want When you use the icon to offset a window trace the Chan Sel selector can be used to select Trace Sep When you set the Chan Sel selector to Trace Sep the vertical offset knob moves the selected trace up or down without moving other traces that show the same channels as the selected trace This lets you visually separate the selected window trace from other window or main traces that may overlap it 3 224 Reference Positioning Window Traces Automatically CSA 863A User Manual Windows The CSA 803A can position your window traces automatically based on an electrical event that occurs on the main trace This triggers the window trace in a manner similar to triggering of the main trace Automatic window posi tioning can only be used on traces that do not use arithmetic operators or trace functions NOTE The limitations on window complexity when automatic positioning is used are identical to the complexity limitations on hardware meas urements You initiate and contro automatic window positioning using the Window Mode pop up menu in the Waveform major menu Touch the Position Mode selector in this pop up menu to set the positioning mode to Auto matic or to Manual See Figure 3 110 WHin
297. partment of the CSA 803A mainframe is always mainframe channel 1 regardless of any reposition ing or omission of sampling heads Complex Trace A trace with a trace expression beyond a single channel specification Any trace using a numeric value a function a reference to a stored trace or an arithmetic operator is a complex trace Control Knob see Knob CSA 803A User Manual Glossary G 2 Cursor Any of four styles of paired markers that you position with the knobs The CSA 803A displays the positions of the cursors and the distance between them in axis units Default Measurement Parameter A value from the default set of measurement parameters The operator can change the default values Whenever a trace is created the meas urement parameters are copied from the default set Distal The most distant point from a reference point As used in the CSA 803A the ending measurement point for timing measurements Dragging The act of changing your touch panel selection by moving your finger without removing it from the screen The selection that is activated is the iast one that you were touching before removing your finger Dual Graticule A display with two graticules Each one is half the height of the single graticule Entry Line A text line that shows your input as you enter selections in a pop up menu Enveloping Displaying a trace that shows the extremes of variation of several acqui sitions GPIB General Purp
298. play You may wish to press different major menu buttons and observe the changes on the display Each major menu presents a group of conirols that are related to each other WAVEFORM controls trace definition sampling head control and acqui sition control m TRIGGER controis triggering m MEASURE controls the automatic measurement system DISPLAY MODES controls histograms mask testing and editing and other display features STORE RECALL controls storage and recall of trace data and CSA 803A settings a UTILITY controis general CSA 803A parameters such as display colors GPIB and RS 232 C settings and the clock You can access the en hanced accuracy system which performs internal calibrations of the CSA 803A and installed sampling heads through the Utility major me nus Example 1 Displaying a Trace Utility Major Menu The Waveform major menu has two pages and the Utility major menu has three pages Press the appropriate menu button to display the first page of the major menu Press the same button a second time to display the second page of the menu Initialize the CSA 803A to default settings using the Initialize selector which appears in the Utility major menu C Step 1 Press the major menu UTILITY button located in the MENUS column If you see a different major menu than that shown on the oppo site page press the UTILITY button again to change the page This illuminates the UTILITY button s lig
299. play mode in which trace data remains on the display as new values are added building a history of all displayed trace points Color grading enables you to visually distinguish the relative density of trace data on the display As trace data values are accumulated areas where more trace record points fall are displayed in a different color from areas where fewer points occur RMantinucusi Figure 2 31 The Persist Histograms Pop Up Menu Operating Basics Example 4 Using Signal Processing v C Step 16 Select Persist Histograms in the major menu and select ON Color Grading in the pop up menu Select Exit to remove the pop up menu After waiting a few seconds for a sufficient amount of data to be acquired observe the colored regions of the trace On the major menu you can select Color Grad Scale to see how colors are assigned to regions of the histogram Select Exit to remove the pop up menu C Step 17 Select Persist Histograms again and select Normal to return to the normal trace display Select Exit to remove the pop up menu CSA 803A User Manual 2 49 Example 4 Using Signal Processing Smoothing Some sampling heads including the SD 24 provide another way to reduce apparent noise To access it you use the Sampling Head Fne s selector in the Waveform major menu C Step 18 Press the WAVEFORM button in the MENUS column and touch Sampling Head Fne s in the major menu In the pop up menu touch 1 or whichever ch
300. point when Vertical Histogram is se lected When horizontal Histogram is selected Pk Pk is the difference between the left most data point and the right most data point within the histogram box m RMSA is the RMS deviation also known as standard deviation u 10 represents the percentage of waveform points which fell within one standard deviation of the mean 20 and 30 represent the percent age of waveform points which fell within two and three standard devi ations of the mean respectively Wims is the number of waveforms that have been acquired since the histogram display was turned on Hits is the number of waveform data points that have fallen inside the histogram box Reference Horizontal Controls The horizontal controls let you set the horizontal size and placement of your traces Touch the horizontal icon lt gt to access these controls Horizontal icon a BPE oer aad at h prea eth sere ge i e KFR d fo i l trigd i y i lt mba nas wesc RAA NEE N ANNNDRISREDO NIR See 3 i i i Knob Labels Pan Zoom Selector Figure 3 51 Horizontai Controls CSA 803A User Manual 3 107 Horizontal Controls Setting Horizontal Size and Position 3 108 You can change the horizontal magnification or size of a trace You can aiso move the trace left or right to see different portions of the trace This is called adjusting the horizontal position To do either of these touc
301. quency per point of the waveform Peak Search Mode 1 Scan the FFT Magnitude waveform to find the nth spectral peak A spectral peak is defined as a waveform peak above a user adjusted reference level 2 Apply the FFT interpolation algorithm described above to find the spec tral frequency Appendices Appendix D Algorithms Max The maximum digitized or calculated data point in the measurement zone of the trace record An overrange value in the trace record will qualify the measurement readout with gt If the trace is null the measurement value will show error Mean WG 1 WY Mean gmp ee ee 2 20 m where m index of left most measurement zone sample n index of right most measurement zone sample WG sampled data point The summation extends over the interval of time corresponding to one period when Data Interval is set to one period or the entire measurement zone when Data Interval is set to the entire zone Mid An overrange value in the trace record will qualify the measurement with gt and an underrange value in the trace record will qualify the measurement with lt If the trace record has both underrange and overrange values the measurement readout will be 0 0000 V If the trace is null the measure ment value will show error Min The minimum digitized or calculated data point in the measurement zone of the trace record An underrange value in the
302. races that represent a single input channel Use the Remove Clr Trace n selector of the Knob menu 2 38 Operating Basics Windows CSA 803A User Manual Example 3 Defining Complex Traces A window is a trace that represents a horizontally magnified portion of another trace A window trace is sampled separately from the main trace it is magnifying Windows are created by touching the Window icon above the graticule C Step 22 Touch the Window icon 59 b6ns S bps div 64 66ns Figure 2 25 A Window Trace Display The CSA 803A automatically added a second graticule with the window trace The main trace was placed on the top graticule and its highlighted portion shows what the window trace is displaying see Figure 2 25 NOTE Window traces can be moved from one graticule to another or combined into a single graticule display In Example 2 when you created a dual graticule display both traces shared the same time base Here the two traces have different horizontal measures because they represent different views of time This can be seen in the graticule labels and the trace descriptions presented in the alternate Trace Status major menu 2 39 Example 3 Defining Complex Traces 2 40 C Step 23 Touch the WAVEFORM button and then touch the More selector in the major menu The original trace is on the Main time base while the currently selected window trace is on a window time base C Step 24 Tou
303. rd m The value 32 767 hexadecimal 8001 represents a data value below the dynamic range of the digitizer This is called underrange Under range values do not appear on a displayed trace m The value 32 767 hexadecimal 7FFF represents a data value above the dynamic range of the digitizer This is called overrange Overrange values do not appear on a displayed trace When a trace function encounters one of these three data values it passes the invalid data value as its output When a measurement encounters one of these three data values the measurement is noted as an error There are exceptions to these rules as noted below All trace functions assume that the trace record contains data other than these three values unless specifi cally noted Absolute Value Abs n Wn for W n 0 Abs n W n for W n lt 0 where n index into the record of data points Win input sampled data point Appendix D Algorithms Average Ayg n Win forp 1 Win Avg _ n Avg n Avg n PINT log 4 p loge 2 fori lt p lt P W n Avg n Avg n Avg n MAE forp P where n index into record of data points Win input sampled data point p record number P total number of records specified for average INT integer part of Differentiate Diff n WO W 0 T forn 0 Diff n Wa 1 Wn 1 27 forisns R 1 Diff R 1 WR 1 WR 2 T foran R 1 whe
304. re n index into the record of data points W n input sampled data point T time interval between successive sampies R record length D 2 Appendices Appendix D Algorithms Envelope Eny n W n forp 1 Env n Minimum of Eny n Wn W n 1 forp gt Landn even 2 4 6 R 1 Env n Maximum of Env n Wa 1 W n forp gt landn odd 3 5 R 2 where n index into record of data points W n input sampled data point p record number R record length P the total number of records specified for enveloping is used only to determine compietion for conditional acquisition when acquisition is stopped on envelope complete Exponential Exp n e where n index into record of data points W n input sampled data point This function is implemented by the 80287 math coprocessor and support ing routines Fast Fourier Transform The instrument computes an integer radix 2 FFT of a complex sequence x n Win jb where Win the time domain waveform point b n 0 X k the compiex sequence representing the Discrete Fourier Transform of the sequence x n is computed as R 1 X k gt x n x wh n 0 Jor k 0R i where R the record length is a power of 2 CSA 803A User Manual Appendix D Algorithms The linear magnitude FFTmag and the phase FFTppase of the FFT are computed as FFT nak YAK BEY Bk F F
305. record of data points W n input sampled data point s smoothing interval Round sf f risetime time per dot x 1 10557 risetime the second argument to Filter where risetime gt 10 ps and lt 50 ms h half interval s 1 2 rounded up R record length in points The centered mode smoothed trace is derived by computing the average value of the corresponding point of the original trace and some number of points of the original trace on either side of the corresponding point The number of points on either side is derived from the smoothing interval the second argument of the Smooth function Near the ends of the trace nonex istent points beyond the ends of the trace are required for averaging The nonexistent points are assumed to be the value of the corresponding end points This method of extending the trace is arbitrary so the results within a smoothing interval of the ends of the trace must be interpreted accordingly Appendices Appendix D Algorithms Shifted Mode Causal Filter Algorithm R Smooth n 4 S won n DWO m 0 forn lt s n Smooth n 1 gt Wim m nAn st forns The shifted mode trace only uses points that occur before the correspond ing point Thus the only points that are assumed occur before the trace not after Integrate Intg n 0 forn 0 m Intg n uwo z Wim vane oe forl san sR where n index into record of data points W n inp
306. remains displayed There are four persistence modes available in the CSA 803A Normal Variable Infinite and Color Grading Pixel A visible point on the display The CSA 803A display is 551 pixels wide and 704 pixels high Each pixel may be set to any of the display colors Pop up Menu A temporary menu that provides an interactive dialog for a specific purpose A sub menu of a major menu Principal Power Switch The master power switch located on the rear panel of the CSA 803A Proximal The point closest to a reference point As used in the CSA 803A the beginning measurement point for timing measurements Record Length The number of samples data points that make up a trace RS 232 C An interface that allows remote computer control of and data capture from a CSA 803A Sample interval The time interval between successive samples in a trace record Sampling Head A high performance amplifier that captures the incoming signal of a channel and reports the sampled data to the CSA 803A Saved Trace Description A specification of a trace that is not displayed Selected Trace The highlighted brightest trace of a multi trace display The selected trace is the trace that is acted on by the knobs and menu selectors Selector An area of a menu that performs some action when you touch it Setting The state of the front panel and sysiem at a given time Software Measurement An automated measurement that is derived from acquir
307. rence values for the measurements established on the selected trace are copied from the current measurement readouts 3 147 Measurements Figure 3 68 Compare amp References Pop up Menu When compare mode is off you can use the knobs or keypad menu to set the reference values A selector appears in the Adjust References section of the Compare amp References pop up menu for each measurement cur rently established on the selected trace Each of these has the word Ref after the measurement name for example the RMS Ref selector Touch the reference selector for the measurement reference you want to adjust and both knobs are set to adjust that reference value Turn either knob or touch either knob label to display the keypad pop up menu to enter the numeric reference value 3 148 Reference Changing Measurement Parameters CSA 803A User Manual Measurements Once you have established a measurement on a trace you can find out more information about the measurement and you can control the way the CSA 803A takes the measurement by changing the measurement parameters Touch the measurement readout selector in the major menu area to see the additional information This displays a pop up menu for the individual meas urement It also displays annotation lines that overlay the selected trace displayed on the graticule These lines snow the value of the measurement parameters that periain to that particular measurement
308. rigger Holdoff Pop up Menu 3 216 Reference Vectored Traces Vectored traces is a display mode that enhances the appearance of dis played traces by eliminating any gaps or discontinuities See Figure 3 106 The trace display area is 512 pixels dots wide When a trace with a record length of 512 samples is displayed each sample has its own unique hori zontal position on the display When traces with record lengths longer than 512 samples are displayed two or more samples must share the same horizontal location For a trace of 5120 samples each horizontal piace shows the results of ten samples When more than one sample shares the same horizontal location the result ing display is always a series of vertical lines called columns that extend from the top sample to the bottom sample The CSA 803A normally does not extend the coiumns to touch adjacent columns so that gaps are shown in the trace You can turn on trace vector ing so that intermediate data is assumed for display purposes and columns are extended to touch adjacent columns Fac lint aL os ae AN co piae E PEX Gi i i gt es R Miva Rs ihe a a ate 5g gns ps dirx P be 4ans Figure 3 106 Identical 512 Point Traces without Trace Vectoring top and with Trace Vectoring bottom CSA 803A User Manual 3 217 Vectored Traces Trace vectoring makes the biggest difference in the appearance of a trace with 512 samples As the record len
309. riod T xX Mm Mp where M first mesial dot number from comparators M second mesial dot number from comparators T time between successive dots of trace D 26 Appendices Color Grading CSA 803A User Manual Appendix D Algorithms Prop Delay PropDelay Dly T x M Db T x M where Diy delay time from trigger to left edge of selected trace T time between successive dots of selected trace M selected trace dot number from comparators Dly delay time from trigger to left edge of second trace T time between successive dots of second trace M second trace dot number from comparators Rise Rise T x Ma Mp where M distal dot number from comparators M proximal dot number from comparators T time between successive dots of trace Width Width T x Mm M m where M first mesial dot number from comparators M opposite slope second mesial dot number T time between successive dots of trace Three algorithms are used to assign colors to the Color Grading display A statistical database is used to track the number of times a waveform point falis on each pixel of the display where each time a data point falls on a pixel it is counted as a hit The algorithms are based on the maximum num ber of hits that have occurred on any pixel in the display In the following algorithms Max is the maximum number of hits For Max gt 15 Hit Density Default
310. ro rho the selected trace must be re moved and redefined However you can also recalibrate the zero rho point for better results 3 31 Cursors 3 32 Once you have positioned the cursors select Proceed The CSA 803A will calculate a constant RHOZERO to be saved with the selected trace The RHOZERO constant is added to the rho position RHOPOS for the selected trace Every time RHOPOS is recalculated for the selected trace for exam ple by baseline correction RHOZERO will be added to RHOPOS again This makes the cursor readout and the automated measurement system more accurate for the selected trace Removing Cursors You can remove cursors by touching the Exit selector in the status area The front panel will return to the previously selected major menu Additional Cursor Facts Once cursors are established on a trace or trace pair touching another trace selects that trace and moves both cursors to it w Split Dots cursors cannot be used on XY traces Other cursor types operate normally on XY traces If the horizontal axis displays time the normal case then the horizontal cursor readout shows the inverse of the delta 1 At which can be used to show frequency The cursor readout also shows the absolute values of the cursor locations and the distance between them A dot cursor is displayed as a vertical bar if it is placed on a trace where trace data cannot be displayed For example if your trace is not trig
311. roceed selector The instrument will calibrate automatically NOTE Some calibrations such as Offset have more than one calibration value Automatic calibration adjusts all the calibrations associated with that parameter To save the current calibration values touch the Store Constants selec tor in the pop up menu Any time you want to restore the calibration to the stored value touch the Recall User Const selector in the pop up menu a When the CSA 803A is powered on the sampling head calibration values are taken from the stored user constants It is a good idea to store calibration values immediately after you finish each calibration w To reset the calibration value to the factory default touch the Recall Defaults selector in the calibration pop up menu CSA 803A User Manual 3 55 Enhanced Accuracy Jo calibrate manually you will need to establish a specific trace display before beginning to calibrate Once the proper trace display is estab lished press the UTILITY major menu button touch Page to Enhanced Accuracy and touch the desired calibration selector in the major menu area Select the sampling head channel you want to calibrate Then touch the Manual Calibrate selector in the pop up menu This assigns the knobs to that calibration You adjust the knobs to see the effect on the trace If the pop up menu is in the way touch the Exit selector to remove it NOTE Once you assign the knobs to calibrate manually t
312. rsors Cursors provide a way to measure the difference between two trace loca tions that you specify Cursors are markers that you position using the knobs Once the cursors are positioned readouts in the Cursors major menu show the absolute locations of the two cursors and the difference A between them m Vertical cursors are a pair of vertical bars The position of the cursors and the horizontal distance between them is shown in horizontal axis units Horizontal cursors are a pair of horizontal bars The position of the cursors and the vertical distance between them is shown in vertical axis units m Paired Dots cursors are a pair of small diamond shaped dots resting on the trace As you move a dot cursor using the knob it follows the trace to the left or right The cursor readout shows both the vertical and horizontal positions in the respective axis units m Split Dots cursors appear similar to paired dots except the dots may be on different traces The readout indicates both the vertical and hori zontal measuremenis in the respective axis units NOTE Consider using the automated measurement system to take meas urements before using cursors You can use cursors to take several measurements However the auto mated measurement system is easier faster and more accurate You can take many common measuremenis using the Measure major menu See Measurements on page 3 137 for more information CSA 803A User Manual 3 29
313. rument They will be available when you power on The following instrument controls are not saved with stored settings and are not changed when settings are recalled x Stored traces a GPIB and RS 232 C parameters except GPIB address is saved m Enhanced accuracy calibrations except Delay Compensate and Time Base Cal Mode are saved a Display colors and intensity audio feedback vectored trace mode and hardcopy mode a Sequence settings mode CSA 803A User Manual 3 175 Stored Settings Storing Settings Use the Store Setting pop up menu in the Store Recall major menu to store a setting After you setup the instrument touch the Store Setting selector to display the pop up menu See Figure 3 81 Menu Displayed with Stored Setting Free NoanvVolatile PAM 2ibS7E amp bates Figure 3 81 The Store Setting Pop up Menu You can choose which major menu you want to be displayed when the stored setting is recalled Touch the selector of the desired major menu in the section of the pop up menu titled Menu Displayed with Stored Setting Both Waveform major menus are listed as options After you choose the major menu you want recalled with the stored setting touch Store Next FPS to store the setting The FPS Front Panel Setting number that will be assigned to that setting appears under the label Set Next FPS if you want to specify a number other than the default you can assign the knobs to set the number by to
314. s A Dual Graticule Display 0 00 cc eee Connections for Example 3 0 eee ee eee The DefTra Pop Up Menu 0 000 Complex Trace Aberration Caused by Off Graticule Component sper ocean Linc acten ee aoe cee etic es Figure 2 24 Figure 2 25 Figure 2 26 Figure 2 27 Figure 2 28 The Chan Sel Selector in the Knob Menu A Window Trace Display 0 0 ccc eee eee The Chan Sel Selector in the Knob Menu Connections for Example 4 00 0 0 A Horizontally and Vertically Expanded Portion of the CalbralOrSiGnabs tice vimnca ae low et iw a e ened es umes Figure 2 29 Figure 2 30 Figure 2 31 Figure 2 32 Figure 2 33 Figure 2 34 The Acquire Desc Pop Up Menu 0 Averaged and Normal Traces 0 2 eseeee The Persist Histograms Pop Up Menu The Sampling Head Fne s Pop Up Menu Connections for Example 5 lt 200 2abve eset lees The Measure Major Menu 0 cae ee ee 2 11 2 12 2 14 2 16 2 19 2 20 2 21 2 22 2 23 2 24 2 26 2 27 2 28 2 31 2 34 2 36 2 36 2 39 2 40 2 43 2 44 2 46 2 46 2 48 2 50 2 53 2 55 xiii _ List of Figures Figure 2 35 The Measurements Pop Up Menu 0 Figure 2 36 Measurements of a Trace 0 00 e eee eee Figure 2 37 The RMS Pop Up Menu and Annotation Lines Figure 2 38 The Default Parameters Pop Up Men
315. s let you choose the other knob parameter for Keypad Menu manipulation Numeric Entri You can use the Keypad Menu to enter a numeric value for your parameter instead of turning the knob until the parameter is set Touch number seleciors as if you were typing the number and end your entry by touching the Enter selector CHS changes the sign of your number Back Space lets you correct errors The p pico n nano H micro and m milli selectors let you scale your number The knob labels always show the knob assignments the parameters that the knobs will control The bottom half of each knob label shows the current value of the parameter When you turn a knob you will see the current value change and you will see the change on the display and on any displayed menus that show the parameter Any time knob labels change they will change color When you turn a knob the fabels return to normal This selector lets you remove a trace from the display First select highlight the trace you want removed by touching it then touch this selector A pop up menu will ask you to select remove or clear See page 3 270 The Coarse Medium and Fine selectors affect the knob resolution When set to coarse each knob click represents a greater change than when set to medium or fine The Set to Min and Set to Max selectors tet you quickly set a parameter to either extreme of its range of adjustment
316. s as signed to set that clock parameter See Figure 3 99 Next to the time and date selectors is a readout showing how many times the CSA 803A has been powered on and how many hours it has been on instrument Qptions 7 Autaoseat ptions Time Date Gntime Powergel Time and Date Selectors Figure 3 99 The Instrument Options Pop up Menu 3 201 Time and Date Displ aying Time and You can display the time and date that a trace was stored by selecting Stored Tra Time Date in the Instrument Options pop up menu of the Date with Stored Utility major menu The time and date for each stored trace appears in the Traces stored trace selectors Time and date can be displayed with stored traces regardiess of whether Stored Tra Time Date was on when the traces were stored When the Stored Tra Time Date display is on the time and date stamp appear underneath any stored trace selector in all appropriate pop up menus including the Recall Trace and Delete Trace pop up menus in the Store Recall major menu the Vertical Desc and Horizontal Desc pop up menus in the Waveform major menu and the Labeling pop up menu in the Utility 1 major menu 3 202 l Reference CSA 803A User Manual Trace Definition and Management Traces are the visible representation on the display of the electrical signal or combination of signals that the CSA 803A samples and digitizes You can define and display up to eight traces simul
317. s div Appendix B Specifications Table B 9 CSA 803 Time Base Specifications Characteristic Specification Internal reference clock Crystal controiled oscillator voltage con trolled oscillator for timebase Sampie rate 200 kHz maximum Record length User selectable 512 1024 2048 4096 or 5120 points Sweep rate resolution 1 2 5 steps or 1 ps div increments Record duration 10 ps to 50 ms Maximum sweep rate 512 point record 1 ps div 1024 point record 1 ps div 2048 point record 2 ps div 4096 point record 5 ps div 5120 point record 5 ps div Time interval measurement 10 ps 0 01 of selected delay accuracy Table B 10 CSA 803 input and Output Specifications Characteristic Specification Touch panel Infrared beam touchable array 22 rows of 11 columns Knobs 2 general purpose knobs set by user to desired function Calibrator output step Voltage 500 mV open circuit or 250 mV into 50 O Frequency Approximately 100 kHz 50 kHz if divide by two mode selected Risetime Approximately 250 ps into 50 Q Internal clock output Synchronized with TDR and calibrator output Voltage Positive pulse from 0 to 2 0 V Source impedance 500 Repetition rate Approximately 100 kHz 50 kHz if divide by two mode selected B 8 Appendices CSA 803A User Manual Appendix B Specifications Table B 11 CSA 803 Trigger Specifications Characteristic Specification Trigger source Trigger mode Auto
318. s for Creating User Masks To ensure the best results when creating masks remember the following and refer to Figures 3 62 and 3 63 w Locate one point along the left edge or right edge of the mask further left or further right than any other You can still create straight lines along the edge just place one point further ieft or right than the others on the edge a Points are connected left to right a All points above the imaginary line between the left most point and the right most point are grouped together as the top All points below the imaginary line between the left most and right most point are grouped together as the bottom Thus an added point that fails below the imaginary line will be added in left to right order to the bottom group of points And an added point which falls above the megmar line will be added to the top group of points Top Bottom These Points Form Dividing Line the Top of the Mask Not Displayed Left Most These Points Form Right Most Point the Bottom of the Mask Point Figure 3 62 Creating a User Mask m if you wish to create a mask with a concave area create several masks to cover the same area Data failing into two overlapping masks is counted only once as part of Total 3 726 Reference Mask Testing Mask With Point Added Below Top Bottom Dividing Line Mask With Point Added Above Top Bottom Dividing Line Figure 3 63 How Points are Connected in a User Mask
319. s highlighted to show that it is the current selection C Step 16 Touch the Fine selector in the pop up menu and turn the bottom knob Observe that the trace movement is now finer than it was before The Keypad pop up menu can also set a parameter to its minimum or maximum using the Set to Min or Set to Max selectors NOTE Look at ihe Set to Min and Set to Max selectors to see the valid range of any parameter C Step 17 Touch the Vert Size M1 knob label Then touch the Set to Max selector in the Keypad pop up menu Vertical size is now the maximum volts per division producing the smallest height trace possibie You can directly enter any value you wish using the Keypad pop up menu _ Step 18 Touch the Vert Size M1 knob label Then touch the following selectors 5 0 m Notice the entry line being formed above the Numeric Entry label in the pop up menu Use Back Space to remove incorrect entries Touch Enter to complete entry Vertical size is now set to 50 mV per division CSA 803A User Manual 2 15 Example 1 Displaying a Trace mer Numeric Figure 2 11 The Knob Menu and Keypad Pop Up Menu 2 16 Operating Basics Major Menu Knob Assignments CSA 803A User Manual Example 1 Displaying a Trace Each major menu assigns the knobs to different parameters Whenever you select a major menu the knob assignments will be the assignments that were in effect when that major menu was active
320. s i H H 3 i i H H f ANC cupa a a oe ye a Labeling i 3 pero Seti a et a a i i TRIGGER MEASURE DISPLAY MODES STORE RECALL UTILITY Use this selector to initialize the instrument to a known state See page 3 113 Use this pop up menu to label traces and settings See page 3 715 CSA 803A User Manual 7 25 At a Glance Use this pop up menu to set Hardcopy parameters See page 3 91 This pop up menu enables you to set the colors of various elements of the display See page 3 21 creen Horizont TRIGGER 2d me Use this selector to w access the Enhanced Accuracy major menu See page 1 27 MEASURE DISPLAY MODES STORE RECALL j AREE ee ees Sar eee H Hutesebh Uptians A 4 UTILITY Autoset controls are Touch this selector to turn the described on page 3 9 audible beep on or off See page 3 7 Turn on or off vectored traces with this selector Touch this selector to assign See page 3 217 the knobs to control display eeeereeeeeae DEGMNeSS Spe pays s4t Control trace scaling a property of traces with this These selectors control FFT selector See page 3 212 windowing and scaling parameters See page 3 65 Select shifted or centered filter mode See page D 6 stamps for stored traces See page 3 181 Bee ze Pate i i Ontime Bs Aaaa P
321. s pop up menu only when an FFT magnitude waveform is selected and only in the Software Mode 3 143 Measurements Statistical Measurement Considerations A number of factors can affect measurements in statistics mode Most of these limitations result from the need to collect histograms to determine the topline baseline and crossings of the trace Note that you must be in color graded mode to use statistics mode Measurements may be incorrect if not enough trace records have been acquired Eye diagrams and signals with significant noise or jitter are examples of signais that will require many trace records for accurate measurements If a rising or falling edge is nearly instantaneous relative to the horizon tal size no data may be acquired on that edge and timing measure ments will be incorrect or will report an error The CSA 803A may not be able to recognize an eye diagram if the the areas above and below the eye crossings are closed or if the proximal and distal levels do not pass through the open areas You may need to adjust the proximal and distal parameters so that they pass through these areas and adjust the mesial so that it does not Refer to the Eye Pattern discussion page 3 61 for additional information If the measurement zone left limit passes through the crossing of an eye diagram the statistics mode algorithm will automatically move the left limit for timing measurements To reset the left limit use the defau
322. s to calibrate manually one for each polarity of TDR puise Calibrate both separately by setting the TDR polarity of the sampling head before making the calibration TDR Polarity is se lected from the Sampling Head Fne s pop up menu of the Waveform major menu After calibrating TDR amplitude check to see that the Reference Amplitude in the Graticules pop up menu is set to match the voltage calibrated here Adjusting Delay Adjust Manually The delay adjust calibration corrects for minor deviations in time coincidence between sampling heads You select which head you want to use as a reference and then calibrate the other heads to that standard Reference CSA 803A User Manual Enhanced Accuracy This calibration is not an attribute of any one sampling head so the values for this calibration cannot be stored in the heads There are no Store Con stants or Recall User Const selectors in the Delay Adjust pop up menu To establish the reference channel you select the desired channel in the Delay Adjust pop up menu and then touch the Measure Reference Chan nel selector The display will show a message for you to connect the calibra tor output signal to the specified channel When you have done so touch the Proceed selector and the system will measure the delay automatically NOTE The two channels of dual channel sampling heads are locked in time coincidence When you have calibrated one channel there is no need to calibrate de
323. s to the desired vertical position The major menu shows the positions of the cursors and the distance between them in Y units a Paired Dots which you move with the knobs to the desired horizontal position The dots float vertically on the trace you cannot contro the vertical position The major menu shows both vertical and horizontal positions of the cursors in graticule units Also if the X units are sec onds the inverse of the distance between the cursors is shown m Split Dots which operate like paired dots but on two different traces of your choice The same information is shown as for paired dots Operating Basics Example 6 Taking Delay Measurements Using Cursors Figure 2 42 The Cursors Major Menu and Cursor Type Pop Up Menu The horizontal bar cursors are used to take amplitude measurements You move them up and down with the knobs to the position you desire See Figure 2 43 Step 9 Touch the Cursors icon and then the Cursor Type selector Step 10 Touch the Horizontal Bars selector Select Exit to remove the pop up menu E Step 11 Use the upper and lower knobs to move the bars over the upper and lower levels of the trace NOTE To precisely position the cursors set the knobs to fine resolution by using the Keypad pop up menu Setting the resolution of one knob changes the resolution of both The major menu area shows the voltage values of each cursor and AV shows the distance
324. sampling head will turn on a red light next to the channel input connec tor indicating that TDR is activated for that channel TDR can be used on each channel independently 2 89 Example 10 Taking TDR Measurements 2 90 Ti L i Status i Main Figure 2 53 The Sampling Head Fne s Pop Up Menu O Step 6 Touch 1 or whichever channel you are using and then TDR Preset to define a trace and turn on TDR O Step 7 Adjust the display sizes and positions to show a trace similar to that shown in Figure 2 54 The vertical and horizontal gt icons will let you make fine adjustments The first rise of this trace is the TDR pulse leaving the sampling head the second rise is the reflection of the pulse returning from the end of the cable Operating Basics Example 9 Creating a Histrogram Display aA lean ce Figure 2 51 A Vertical Histogram Display You can adjust the histogram limits to restrict the range of trace record points that the CSA 803A will recognize as valid data points g Step 11 Touch Persist Histograms to redisplay the pop up menu C Step 12 Select Vertical Limits in the pop up menu The knobs are now assigned to Top and Bottom O Step 13 Use the knobs to adjust the top and bottom limits of the histo gram and observe the changes in the distribution displayed Note that in Infinite Persist mode changing a limit causes all trace data to be cleared and new data to be
325. se The Noise measurement is available only in statistical measurement mode 1 Find the leftmost mesial crossing using timing histograms This horizon tal value is Cross lf no mesial crossing is found set Acenter midway between the measurement zone Left and Right limits 2 Ifa first mesial crossing was found find the second mesial crossing using timing histograms This horizontal value is Cross If no second mesial crossing is found set Acenter midway between Cross and the measurement zone Right Limit 3 ifa second crossing was found center hcenter between Cross and Cross for an eye diagram the center of the eye 4 Set the left and right limits of the histogram at hcenter 5 lf Noise Location is Baseline then center the top limit of the histogram midway between the topline and the baseline and set the bottom limit at the bottom of the graticule 6 If Noise Location is Topline then center the bottom limit of the histogram midway between the topline and the baseline and set the top limit at the top of the graticule Appendices Hardware Measurements CSA 803A User Manual Appendix D Algorithms 7 Collect a vertical histogram within these limits If the histogram is empty and the trace is not recognized as an eye diagram then set Acenter midway between the first crossing and the Left limit of the measurement zone and measure the Noise from a vertical histogram within the limits determined Phase
326. se the Graticules pop up menu in the Waveform major menu The section of this pop up menu labeled Y Units governs the vertical axis units You can touch either the Volts or Rho selectors to set the vertical axis labels to those units The current setting is highlighted Rho is not selectable unless the following are true a The selected trace can be displayed in Volts units as opposed to U or N units Traces such as Log M1 or M1 M2 are not scaled in Volts and therefore cannot be scaled in Rho Any linear combination of channels and stored traces can be displayed in Volts or Rho s TDR must be on in ali channels in the selected trace 3 87 Graticules 3 88 The Reference Amplitude selector assigns the knobs to control the rho reference amplitude This has meaning only when the vertical axis units are rho For TDR measurements the rho reference amplitude should be set to the absolute amplitude of the TDR pulse sent by the sampling head A voltage change equal to the reference amplitude corresponds to a change in rho of 1 The Baseline Correction selector is discussed in Baseline Correction page 3 17 in this manual The baseline correction feature of the CSA 803A is used to hold the vertical position of a trace on the display when the TDR pulse level shifts due to a change in termination impedance This selector appears in the Y Units section of the Graticules pop up menu because the feature is most useful when TDR puls
327. se the stored trace as a basis for compar ing other traces This is similar to Exampie 7 where you used a reference measurement as a basis of comparison This time the entire trace will be saved as a reference For this example you will need a CSA 803A with at least one sampling head instalied and one SMA connecting cable O Step 1 Initialize the CSA 803A press the UTILITY button in the MENUS coiumn touch Initialize in the major menu and touch Initialize in the verification pop up menu C Step 2 Put on the wrist strap and ensure that it is connected to the antistatic connector on the front panel of the CSA 803A CO Step 3 Connect the CALIBRATOR output to any sampling head input m al d wd pe wd C3 Figure 2 48 Connections for Example 8 C Step 4 Press the TRIGGER button and select Source in the Trigger major menu Select Internal Clock and touch Exit to remove the pop up menu C Step 5 Press the SELECT CHANNEL button on the sampling head input you have connected to the CALIBRATOR signal C Step 6 Press UTILITY Instrument Options and Vectored Trace for a vectored trace display CSA 803A User Manual 2 81 Example 8 Comparing Traces to Stored Traces C Step 7 Press the AUTOSET button You should have a stable display of the calibrator signal showing several cycles Make sure that all of the signal is on the display and that there are no places where the trace extends above or below the graticule
328. selector to assign the two knobs to these parameters C Step 16 Touch the RMS selector in the major menu to remove the pop up menu The knob assignments remain after the pop up menu is removed so that you can set the limits without a menu covering part of the display C Step 17 Turn the top knob clockwise so that the left limit bar moves into the area of the trace previously highlighted When you used the limit bar to exclude the portion of the trace where the measurement was being taken the CSA 803A took the measurement at the next opportunity on the trace This is shown by the highlighted portion of the trace moving to the right This new left limit is effective for all measurements on this trace including the frequency measurement CSA 803A User Manual 2 59 Example 5 Taking Automated Measurements Default Measurement Parameters 2 60 Left and right limits are examples of measurement parameters Measure ment parameters are settings that you change to control the measurement system Most parameters are shared by all the measurements being taken on any one trace This means that each trace has an associated set of measurement parameters If you are taking measurements on several traces and want them all to have the same parameters you can set the default parameters before creating any of the traces Each time a trace is created its measurement parameters are copied from the default parameter set In addition you c
329. sition assersrne ies Rooted emo hanks 3 102 Changing the Display Update Rate 3 104 Changing Scaling 2 6647 8c4 Gees nOnrortiand ube vance ee tes 3 105 Clearing the Histogram Data 0 0 00 c cee ee 3 105 The Histogram Readout 0002 cee en ee encenenevanee 3 106 Horizontal Controle cis ss sie eies caren cas oleae ore er eee ae ea 3 107 Setting Horizontal Size and Position 0040e000s 3 108 Interactions With Other Traces 00 cence eens 3 108 Pan ZOOM oeaan Ena deere Gee aan a a sew ane 3 109 Changing the Horizontal Reference Point 3 111 CSA 803A User Manual vii Table of Contents Initialization ean week ei ocd pea Giw eer a Ghee tees ee asa sees 3 113 initializing and Erasing Nonvolatile RAM e805 3 114 Labeling 2 sori sir oe Gewese sete seu ideo A a Ged 3 115 Creating Labels ic di tapes npr dado BEE Er EAE a 3 116 Displaying Labels with Traces ussunnessuenoniveusnso 3 118 Mask Testing s iienascarwnuenes vas edr e ia ara aaaea 3 119 Using Predefined Telecommunication Masks 3 121 Selecting a Predefined Mask 0 00 cece ee eee 3 122 Creating Masks vic siy caso eds epaaaveee verse eabeee vee 3 124 Deleting User Masks oc cste casayud aah tsdanaieee acta 3 125 Hints for Creating User Masks 0 0 0 cee cae ee cee ee 3 126 Storing Mask Definitions 0 cece eee eee ees 3 127 Modifying
330. splay is easy press the SELECT CHANNEL button of the sampling head channel you wish to add g Step 13 Press the sampling head channel button of the signal from the INTERNAL CLOCK output You should be aware of several important points about this display see Figure 2 15 m Both traces share the same time base and so both traces display the same span of time The horizontal axis labels apply to both traces This may not hold true for the vertical axis m While the CSA 803A can display up to 8 traces at once there is always one selected trace The selected appears brighter than other traces Most menu selectors the knobs the status displays and autoset all operate on the selected trace The CSA 803A can display four different colors so that when up to four traces are displayed each trace is dis played in a different color If greater than four traces are displayed additional traces are displayed in the same colors used for the first four traces m The graticule axes and the axis labels are the same color as the selected trace The channel lights on the sampling head are lighted to show that both channels are being displayed The light for the selected trace blinks Ee T ae ee 691 9ns Bas diu 58 6946 Figure 2 15 Graticule with Two Traces 2 22 Operating Basics Selecting Traces by Touch CSA 803A User Manual Example 2 Managing Multiple Traces To select a different trace simply touch the desired tra
331. splays the next setting to be recalled When you have stored all the settings you want to sequence through and have enabled sequencing use the SEQUENCE SETTING button to recall the next setting of the sequence This button is located above the sampling head compartments near the ON STANDBY switch The SEQUENCE SETTING Button ACQUISITION AUTOSET HARDCOPY i am d aoe a C Figure 3 84 Front Panel SEQUENCE SETTING Button 3 179 Stored Settings 3 180 Reference CSA 803A User Manual Stored Traces A stored trace is a trace record of a single acquisition cycle You can think of itas a snapshot of a trace In normal acquisition mode the stored trace is the same as the trace record on the display For traces acquired in variable persistence infinite persistence or color grading modes only the current 512 point trace record is saved not the entire history of displayed points Once you have stored a trace you can use it as an element of trace expres sions in other traces For example you could define a trace to be M1 STO3 This trace acquires data from sampling head channel M1 and subtracts from each sample the data recorded in stored trace number 3 Stored traces are saved when you power off the instrument and are avail able when you power it on again 3 181 Stored Traces Storing Traces When you store a trace the instrument takes a copy of the trace record of the selected trace The trace record is always
332. ss the DISPLAY MODES button and then touch Standard Masks Then touch the desired mask label for the signal displayed After selecting a standard mask the CSA 803A performs the following ifauser mask not predefined is currently displayed the instrument will ask you to store the mask in a setting If you choose not to store the mask it is removed If a standard mask is currently displayed it is removed without asking you to store it because any standard mask can easily be selected again w The CSA 803A displays the mask you selected a The CSA 803A resets the time per division setting appropriate for the selected mask Note however that you are free to change the time per division setting without altering the mask The instrument updates the two line Standard Masks label on the Display Modes major menu to indicate which mask is displayed 3 122 Reference CSA 803A User Manual Mask Testing The instrument displays the message A front panel AutoSet will now use a mask specific algorithm while in the Display major menu This means that the autoset function is now modified to perform an autoset to the signal characteristics of the selected standard mask You can choose to have the instrument perform this Autoset to Standard auto matically whenever you select a standard mask from the Standard Mask pop up or to perform Autoset to Standard only when you push the Autoset button This feature is controlled from the Instrument Op
333. ssfully the instrument will return to the state it was in before the self test ran In the case where the self test diagnostics were executed after power on the instrument will return to the state it was in when last powered off if the self test diagnostics fail the Extended Diagnostic menu is displayed and the failure is noted on the display You can exit the extended diagnostic system and try to use the instrument but until the failure is repaired you should not rely on any measurements taken Cail your service person to repair the cause of any failures 3 37 Diagnostics Extended You can enter the extended diagnostic system by touching the Extended Dia gn ostics Diagnostic selector located in the Utility2 major menu press the UTILITY button until the Utility2 menu appears and then touching Extended Diag nostic in the verification pop up menu When self test diagnostics fail the extended diagnostic system is entered automatically See Figure 3 17 Figure 3 17 The Extended Diagnostic Pop up Menu in the Utility2 Major Menu The extended diagnostic system is an independent subsystem of the instru ment While in this system few of the front panel buttons operate and the Extended Diagnostics menu covers the entire display To leave the extended diagnostic system and return to normal instrument operation touch the E Exit selector in the extended diagnostic menu twice The instrument will return to the state it was in be
334. ssigning Trace Colors Setting the Display Intensity CSA 803A User Manual Color Display Aithough the four trace colors are assigned to traces in order as they are created you can change a trace s color assignment using the Selected Tra Color selector at the bottom of the Color pop up menu The status area below the Selected Tra Color shows the trace number of the selected trace and the number of the color assigned to that trace for example Trace Color 1 The box next to the selector displays the color of the trace Touch the Selected Tra Color selector to change the color assignment of the selecied trace As you touch the Selected Tra Color selector it cycles through the four trace colors and window trace color Touch the Window Trace selector to change the color assignment of the window trace You can adjust the overall intensity or brightness of the display Touch the Display intensity selector in the Color pop up menu to assign the knobs to control the intensity of the display Display intensity can be from 0 to 100 3 23 Color Display RA AE Etat Tr HHH HTH Sri HHHHGMVHAN Hr eer rRNA YHA i SSAA HHA hr AA a a 3 24 Reference Displaying a Constellation Diagram CSA 803A User Manual Constellation Diagrams A constellation diagram is the result of displaying one data signal against another in an XY format resulting in a matrix display of the various signal levels This section provides general instructions to
335. supported For ali types of traces including random data such as eye patterns Color graded mode oniy One trace per graticule Affected by dis played vertical size and trace functions g averaging smoothing and the use of dual graticules Updated when color graded data base is updated selectable be tween 5 and 100 seconds or when a measurement parameter changes such as mesial level CSA 803A User Manual 2 63 Example 5 Taking Automated Measurements Figure 2 39 The Hardware Measurements Pop Up Menu You have now converted all your measurements on this trace to hardware measurements Since hardware measurements cannot support amplitude or area energy measurements these do not appear in the pop up menu and the RMS measurement has been removed from the major menu area See Figure 2 39 The third measurement mode is Statistics Mode Statistics measurements can be selected only when the color grading display mode is enabled All measurements are selectable in Statistics Mode except for the three fre quency domain measurements spectral frequency spectral magnitude and THD Noise Jitter and SNR measurements which cannot be selected in software or hardware measurement mode are selectable in statistics mode C Step 22 Press the UTILITY button to display the Utility major menu Touch the Instruments Options selector in the major menu then touch the Autoset Mode selector in th
336. t mu Filtering assigns a knob to set the number of successive trace sam ples that must cross the transition level before the transition is counted as valid Noisy signais will be affected most by filtering This affects only an automatic window with tracking on or an automatic window when locate window is performed Level Mode selects between Absolute you specify the transition level in terms of volts or Relative you specify the transition level in terms of percentage of baseline to topline height of the trace m Level assigns a knob to set the transition voltage level in the mode determined by the Level Mode selector Tracking This affects only an automatic window with tracking on or an automatic window when locate window is performed Three types of tracking are available Relative tracking Baseline and topline are recalculated and used to calculate an absolute level Window position is then found using that absolute level Absolute tracking Absolute level used to find window position No tracking either No position change until Locate Window is selected A Relative tracking or Absolute tracking measurement is performed once each time Locate Window is selected Locate Window meaningful only when Position Mode is Automatic and Tracking is Off tells the CSA 803A to position the window trace 3 226 Reference CSA 803A User Manual Windows Top Base Method allows you to selec
337. t any trace There are three methods that you can use to select a trace touch the trace on the display or on its displayed label use the All Trace Status major menu or use the sampling head SELECT CHANNEL button Selecting Traces by Touch The fastest way to select a trace is to touch it on the display or on its dis played label When you touch the graticule area of the display a box is displayed that shows the boundaries of your touch If a single trace passes through the boxed area when you remove your finger that trace will become the selected trace The touch box disappears when you withdraw your finger and select a trace You can drag your finger across the display to change the position of the box before you remove your finger to select the trace If several traces pass through the area indicated by the touch box one becomes the selected trace when you remove your finger Touching the same area repeatedly will select different traces You can select traces by touching the same spot on the display repeatedly until the trace you want is selected Selecting Traces Using the Trace Status Menu You can see the status of all displayed traces at once by using the Trace Status menu You are shown the trace number the first part of the trace expression the time base and the vertical and horizontal size per division To view this information touch the More selector in the Waveform major menu The entire Waveform major menu is repl
338. t the method of determining the topline and baseline You can choose between the standard IEEE meth od histograms or an alternate method that smooths and differentiates the waveform data before calculating topline and baseline The alternate method works better than the IEEE method for ramps triangular or irregular square waves The Top Base Method parameter affecis all window traces It also affects how automatic measurements are performed on all traces You can also change this parameter from the Measurements pop up menu in the Measure major menu 3 227 Windows 3 228 Reference CSA 803A User Manual XY Traces Most traces show a signal voltage the vertical axis as it varies over time the horizontal axis You can display a trace that shows how two traces compare with each other independent of time Such an XY trace shows the signal voltage of one trace on one axis against the signal voltage of the other trace on the other axis See Figure 3 111 ru s5 Simy five Boa 3 ive ELI f eonenna SETON EREE 25i mY Saaved iu 249 SmY Figure 3 111 An XY Trace NOTE You can have only one XY trace You cannot take measurements of XY traces This XY trace is a constellation diagram Constellation diagrams are discussed on page 3 25 When an XY trace is displayed the axis units cannot be changed from volts on either axis 3 229 XY Traces Horizontal Description J i GScquiring Timeb
339. taneously You define a new trace on the main time base by entering a trace expres sion A trace expression is a description of the signal sources and mathe matical computation that determines the trace display An example of a simple trace expression is M1 which specifies that a trace should show the signal source of mainframe channel 1 with no mathematical computation The trace defined by this trace expression displays the signal that the CSA 803A samples and digitizes from the specified sampling head input channel An example of a complex trace expression is Log M1 M2 which specifies that the signals from mainframe channels 1 and 2 are to be algebraically added and the base 10 log of the sum is to be shown as the final trace 3 203 Trace Definition and Management Defining New Traces NOTE You define traces on a window time base using the Window icon described on page 3 223 Defining Traces Using the DefTra Icon You enter trace expressions using the DefTra icon A DefTra icon appears above the top right corner of the graticule or graticules on the display Touch the DefTra icon above the graticule on which you want to define a new trace When you touch the icon a blank DefTra pop up menu is displayed This pop up menu covers the entire display as shown in Figure 3 100 You use the selectors of the DefTra pop up menu to type your trace ex pression As you type the trace expression you are building appears at the t
340. th inside dimensions at least 15 cm 6 in taller wider and deeper than the instru ment The shipping carton must be constructed of cardboard with 375 pound test strength Step 2 If you are shipping the CSA 803A to a Tektronix field office for repair attach a tag to the instrument showing the instrument owner and address the name of the person to contact about the instrument the instrument type and the serial number C Step 3 Wrap the instrument with polyethelene sheeting or equivalent materia to protect the finish O Step 4 Cushion the instrument on all sides by tightly packing dunnage or urethane foam between the carton and and the instrument allowing 7 5 cm 3 in on each side O Step 5 Seal the carton with shipping tape or an industrial stapler Appendices Trace Functions CSA 803A User Manual Appendix D Algorithms Digitized traces are a sequence of samples stored as16 bit signed integers The samples are numbered from 0 through the record length less one a 512 point record numbers samples from 0 through 511 Three sample values represent invalid data points u The value 32 768 hexadecimal 8000 represents nul an unacquired data point A trace that is defined but has never been acquired contains null values Clearing a trace fills it with null values A trace is either completely filled with null values or it contains no null values null values and non null values cannot coexist in the same trace reco
341. th selectable 1 x 10 x attenuation and AC DC coupling m AC coupled trigger prescaler to 10 GHz except Option 10 m Single ended and differential TDR measurements are available on all channels using SD 24 sampling heads 1 7 Introduction Automatic measurement capability that allows a wide variety of complex measurements on a signal and gives real time updating Twenty eight measurements are available including rise time fail time rms voltage delay width duty cycie and frequency Measurement statistics provide the mean and standard deviation of your measurements Measurements can be based on data in the color grading database for example fully automatic noise and jitter measurements Fast fourier transform capability that allows you to obtain a frequency domain display of a given trace You can display the FFT magnitude and FFT phase of the trace s A unique statistical measurement mode that allows pulse parameter measurements on random data for example eye diagrams as well as accurate timing measurements in the presence of jitter Major Menu Buttons Control Buttons Display and gt Touch Panei Knobs Power only Sampling Head Compartments Compartments s An Autoset function that allows quick adjustment of settings by pressing a single button m Menu driven touch screen operation that simplifies operator control of the CSA 803A It disables invalid selections and indicates to the operator
342. the internal circuit impedance is 50 Q and the connector imped ance is 50 Q This causes the acquisition point to rise to 250 mV The transition propagates to the open in the device under test and is re flected back to the acquisition point causing the voltage at the acquisition point to rise to 0 mV At the acquisition point the time displayed from the first step to the second step is the propagation time from the acquisition point to the open in the device under test and back See Figure 3 92 Baseline Correction Baseline correction is a feature of the CSA 803A instrument This feature holds the displayed baseline of a trace in one location despite variations of the offset in the sampling head These offset variations are caused by changes in impedance at the device under test as just described Baseline correction is especially useful with TDR TDT measurements With out baseline correction changes in the DC resistance to ground for the cable or device under test would cause the entire step to move vertically on the display Baseline correction keeps the baseline in one location vertically For the CSA 803A you can enable baseline correction from the Graticules pop up menu However if you use the TDR Preset selector to set up for TDR mea surements baseline correction is automatically turned on For more informa tion on baseline correction see page 3 17 3 191 TDR Example Taking TDR Measurements 3 192 This example d
343. tions pop up menu under the Utility major menu Note that the Autoset to Standard feature is only availabie for standard masks and is not avail able for masks that you create or modify except for the User Eye See Autoset on page 3 9 and Autoset Options on page 3 10 for more in formation You can also create a new mask that uses a standard mask as a base See Creating a New Mask from a Standard Mask page 3 128 Note that for all standard masks except eye pattern masks if you press the AUTOSET button or configure for automatic autoset the instrument auto matically turns on waveform averaging See Averaging and Enveloping page 3 13 and Autoset page 3 9 To perform testing using standard masks see Starting Mask Testing on page 3 130 3 123 Mask Testing Creating Masks A user mask is created by moving a cross hair cursor on the display and adding or deleting points as required You can edit or use the masks at any time by selecting the Mask Testing pop up menu from the Display Modes major menu See Figure 3 60 To create a mask press the DISPLAY MODES button and then touch Mask Testing This brings up the Mask Testing pop up menu To create a new mask select any one of the MaskN labels for example Maski Next touch Edit Mask Definition This displays the mask editing screen A cross hair cursor is located at the center of the display The cursor is moved by turning the knobs The upper knob is assigned to Mask Cursor
344. tions to this method The channel must not be displayed as part of any other trace being displayed If the yellow channel light is on either steady or blinking this method of defining a trace cannot be used a The trace expression will consist only of this channel You cannot use this method to enter complex trace expressions Trace Numbers When you define a new trace the CSA 803A assigns it a trace number Trace numbers range from 1 through 8 New traces are assigned the lowest available number Once a number is assigned to a trace the number does not change CSA 803A User Manual 3 207 Trace Definition and Management Selecting Traces When you define a new trace it is highlighted bright intensity on the dis play This indicates that it is the selected trace When multiple traces are displayed there is always one selected trace The graticule labels and axes match the color of the selected trace The selectors knobs and buttons operate on the selected trace The graticule axis labels show the vertical and horizontal size and position of the selected trace Selectors that show trace status such as the Vertical Desc and Horizontal Desc selectors in the Waveform major menu show the status of the selected trace When you use the gt and icons to assign the knobs to horizontal or vertical size and position the knobs affect the se lected trace When you have more than one trace on the display you can select and highligh
345. tivated for that channel TDR can be used on each channel independenily Reference TDR E Step 6 Adjust the display sizes and positions to show a trace similar to that shown in Figure 3 94 AUTOSET may make this job easier and the vertical and horizontal lt gt icons will let you make fine adjust ments reer Figure 3 94 TDR Step and Reflection The first rise of this trace is the incident TDR step leaving the sampling head the second rise is the reflection of the step returning from the end of the cable Changing Graticule Units for TDR The units of measure commonly used in TDR are units of rho p measured on the vertical axis and time on the horizontal axis You can change the measurements by using the Graticules selector on the Waveform major menu CSA 803A User Manual 3 193 TDR Figure 3 95 The Graticules Pop up Menu m Step 7 Touch Graticules in the major menu and Feet Meters or Inches in the pop up menu see Figure 3 95 If you know that the propagation velocity of your cable differs from the default touch the Propagation Velocity selector and adjust this parameter If you don t know the velocity or are using Tektronix SMA cables accept the 0 7 default This unitless number represents the fraction of the speed of light that signals pass through your network or transmission line If you don t know the propagation velocity but you know the dielectric constant of the transmissi
346. to your printer manual for the proper printer settings Installing the Printer Connect the printer to the CSA 803A Depending on the printer you will want to use the PRINTER connector the GPIB connector or the RS 232 C connector See Figure 3 44 RS 232 C Connector GPIB Connector Figure 3 44 Printer Connectors on Rear Panel a PRINTER is the appropriate connector for Centronics compatibie printers This is the standard interface for the CSA 803A and no special configuration of the CSA 803A is required GPIB is the General Purpose Interface Bus parallel interface connector Use a standard cable fifteen meters or less in length If you are not using a controller to initiate the hardcopy set the GPIB Mode parameter of the CSA 803A to Talk Only and set the printer to Listen Only or Listen Al ways mode address 31 Setting GPIB parameters is explained on page 3 80 CSA 803A User Manual 3 89 Hardcopy e RS 232 C is a serial interface connector Use a standard straight wired ae cable with male connectors on both ends Hard flagging is used so all Os lines must be connected Do not use a null modem cable The CSA 803A acts as a DCE device Connecting the CSA 803A to a com puter also requires a straight wired cable but soft flagging may be used The RS 232 C parameters baud rate parity and number of stop bits of the CSA 803A should be set to match those of the printer or computer When you connect a printer to the RS 232
347. tometry TDR and smoothing functions cannot be r controlled from the sampling head front panel These functions are con Smoothing Functions trolled using the Sampling Head Fne s pop up menu in the Waveform major menu The left part of the Sampling Head Fne s pop up menu lets you select the sampling head channel on which to set TDR or smoothing The selectors in the right part of the pop up menu always reflect the status of the TDR or smoothing for the sampling head channel selected in the left part Time Domain Reflectometry TDR and Time Domain Transmission TDT Time Domain Reflectometry or TDR is a method of characterizing a trans mission line or network by sending a signal into one end and monitoring the electrical reflections Some sampling heads have a TDR feature A TDR step can also be used to make Time Domain Transmission TDT measurements TDT is a technique that allows you to measure the response of a system by sending steps through a device and monitoring the output of the device on another channel The measurements are made on signals transmitted through the device rather than reflections from the device as in TDR The selectors in the Head Type section of the Sampling Head Fne s pop up menu see Figure 3 80 let you contro the TDR functions of a sampling head that has the TDR feature The TDR TDT selector turns the feature On or Off The TDR Polarity selector sets the polarity of the TDR step to or TDR
348. trace record will qualify the measurement readout with lt If the trace is null the measurement value will show error Over Shoot Max topline OverShoot 100 x _ topline baseline lf the values of topline and baseline are equal the measurement value will show error CSA 803A User Manual D 17 Appendix D Algorithms Peak Peak PeakPeak Max Min An overrange value in the trace record will qualify the measurement with gt and an underrange vaiue in the trace record will qualify the measurement with lt If the trace record has both underrange and overrange values the measurement readout will be qualified with If the trace is null the meas urement value will show error Period 1 Search the measurement zone for the left most mesial crossing of positive slope Continue the search to the right to find the first upper signal noise ratio level crossing to the right of the first mesial crossing The horizontal coordinate of this crossing is Cross 2 Search the measurement zone for the left most mesial crossing of negative slope Continue the search to the right to find the first lower signal noise ration level crossing to the right of the second mesial cross ing The horizontal coordinate of this crossing is Cross 3 If Cross lt Cross set Cross Cross Cross Cross and Slope positive If Cross gt Cross set Cross Cross Cr
349. transition The time displayed from the first transition to the second transition is the propa gation time from the acquisition point to the short in the device under test and back See Figure 3 90 Figure 3 90 Step Generator with a Shorted Output Operation Into a 50 O Load Initially the diode switch is conducting Since the step generator output is connected to a 50 Q load the resistance to ground at the acquisition point is 25 Q because of the internal 50 O impedance The 10 mA current source places 250 mV at the acquisition point Figure 3 91 Step Generation with a 50 Q Load When the diode switch opens reverse biased the return path to ground is broken and the acquisition point rises to 0 V The matched impedance allows the acquisition point to remain at 0 V See Figure 3 91 Operation Into an Open Circuit Initially the diode switch is conducting Since the step generator output is open the resistance to ground at the acquisition point is 50 Q because of the internal 50 QO impedance The 10 mA current source places 500 mV at the acquisition point as a starting condition Reference CSA 803A User Manual TDR 0 y mnnn snme oamon oonmmaoe omron oomen omeen oomen manana 250 mY 500 mV Figure 3 92 Step Generation with a 50 Q Load When the diode switch opens reverse biased apparent resistance to ground at the acquisition point and at the channel connector is 25 O because
350. ts then adjust the horizontal size and position to show the complete rising or falling edge Hardware measurements described on page 3 143 are an exception Hardware measurements are not taken from the displayed data and are not affected by the vertical size settings Hardware measurements are howev er affected by horizontal settings Once the trace display is established press the MEASURE button to display the Measure major menu Initially this menu is mostly blank The six empty selectors are reserved as places where measurement readouts will appear when you select your measurements See Figure 3 66 Figure 3 66 Measure Major Menu Touch the Measurements selector to display a pop up menu with all the measurement selectors available Touch the individual measurement selec tors to take measurements of your trace As you select each measurement the result of the measurement is immediately displayed in one of the selec tor areas of the Measure major menu The illustration below shows the Measurements pop up menu with two measurements Frequency and RMS selected The numeric readouts for these two measurements are in the major menu area See Figure 3 67 3 140 Reference Measurements ooe Areakner gu i i Aime litude Select measurements here j d t K aas poe 4 t x Remove the pop up mmm menu here i View the aes readouts here i i Figure 3 67 M
351. tting or settings to delete by touching the selectors in the top part of the pop up menu see Figure 3 83 If more than 15 settings are stored touch PageT and Page to scroll through the menu As you touch these selectors they highlight to show that they will be deleted when you touch the Delete Selected Settings selector Touch a highlighted selector a second time to remove it from the list of settings to delete The All Settings selector is a quick way to select all the stored settings Figure 3 83 The Delete Setting Pop up Menu 3 178 Reference Sequencing Through _ Stored Settings CSA 803A User Manual Stored Settings if you have several settings saved you can quickly cycle through the set tings This is useful if you have a series of test set ups that you want to use repeatedly The sequencing order of stored settings is the same as the order in which they appear in the Store Setting pop menu That is settings will recall or sequence in ascending numerical order Therefore you must set the se quencing order of stored settings by choosing the appropriate numbers for those stored settings Enable sequencing of settings by touching the Sequence Settings selector in the Store Recall major menu This selector can set sequencing to On or Off When this selector is set to Off the SEQUENCE SETTING button on the front panel see Figure 3 84 does not operate When it is set to On the Sequence Settings selector di
352. tween successive points on the trace record This is different from the sampling rate which is the actuai time that it takes to sample and digitize the successive points in the trace record Since only one point is sampled and digitized after a trigger event the sampling rate is much slower than the sample interval To compute the sample interval divide the time period that the trace record displays by the number of points in the trace record For example if you are display a trace at 20 ns per division the trace displays a little more than 200 ns of time There are a few points outside the 10 division graticule on either side If the trace has 2048 points the sampie interval is 200 ns di vided by 2048 or 100 ps All traces on the main time base have the same record length and horizontal size Similarly ail traces on window time bases share the same record length and horizontal size This means that the CSA 803A uses one sample interval for main traces and a different sample interval for window traces You can see what the current sample intervals are by looking at the top of the Horizontal Desc pop up menu in the Waveform major menu Reference Controlling Acquisition CSA 803A User Manual Acquisition You can freeze the traces on the display at any time by pressing the ACQUISITION button This button is found above the sampling heads near the column of major menu buttons This technique lets you stop live traces to examine the
353. u Figure 2 39 The Hardware Measurements Pop Up Menu Figure 2 40 A Jitter Measurement on the Calibrator Signal Figure 2 41 Connections for Example 6 005 Figure 2 42 The Cursors Major Menu and Cursor Type Pop Up WOOO ip oi we Os murs sen ale vale whites Rare ee te Ne WS eee Figure 2 43 Horizontal Bar Cursors Placed Over a Trace Figure 2 44 The Cursor Type Pop Up Menu in Split Dots Mode Figure 2 45 Connections for Example 7 1 0 0 ccc ee eee er ee eee Figure 2 46 The Graticules Pop Up Menu 005 Figure 2 47 The Compare amp References Pop Up Menu Figure 2 48 Connections for Example 8 0 2 6 ccc eee ees Figure 2 49 The Store Recail Major Menu and Store Trace Pop Up MER coin ta teen tad a EENE E e Baad eke Bee Figure 2 50 Connections for Example 9 cece ee cena Figure 2 51 A Vertical Histogram Display Figure 2 52 Connections for Example 10 000005 Figure 2 53 The Sampling Head Fne s Pop Up Menu Figure 2 54 TDR Step and Reflection 2 0 ccc eee eee ee Figure 3 1 Acquisition of a Trace LS ick ited RE hee SEA OS pate Figure 3 2 Front Panel Acquisition Lights 2 2 0 0 cece eee Figure 3 3 The Acquire Desc Pop up Menu 0 0 eee Figure 3 4 The Clear Trace Pop up Menu 0 0 05 Figure 3 5 The Instrument Options Pop up Menu
354. uch the trace to select it C Step 3 To average the trace press the WAVEFORM button touch the Acquire Desc selector in the major menu and then touch the Average N selector in the pop up menu See Figure 3 8 Cj Step 4 To envelope the trace press the WAVEFORM button touch the Acquire Desc selector in the major menu and then touch the Envelope N selector in the pop up menu The Vertical Desc selector status shows that the average or envelope function is part of the trace expression Reference Terminating Averaging or Enveloping Record Count Averaging and Enveloping Figure 3 8 The Acquire Desc Pop up Menu When you want to return to normal trace display touch the Average N or Envelope N selector in the Acquire Description pop up menu Several complete trace records are combined to form an averaged or envel oped trace You can set the number of records that the CSA 803A accumu lates and combines Use the Set Avg N and Set Env N selectors in the Acquire Desc pop up menu to assign the knobs to set the number of records The top knob sets the number of records to accumulate for an average and the bottom knob does ithe same for enveloping when you also limit acquisitions You can set the instrument to limit acquisitions for enveloping or averaging See imitng Acquisition in this section Each knob click changes the current value by a multiple of two in the coarse setting You can use the numeric keypad to enter speci
355. uching Set Next FPS You can choose any number from 1 to 9999 If you choose a number that is already in use the word Exists appears under the Store Next FPS label If you store the setting under that number the previously stored setting using that number will be deleted You can also replace an existing stored setting with the current setting by touching one of the selectors in the top haif of the Stored Setting pop up menu 3 176 Reference Recalling Stored Settings CSA 803A User Manual Stored Settings The Store Setting pop up menu keeps track of the amount of non volatile RAM available to store both settings and traces This information is listed under Free NonVolatile RAM This number will decrease after you store settings or traces and increase after you delete settings or traces You can recall a stored setting using the Recall Setting pop up menu in the Store Recall major menu see Figure 3 82 Touch the FPS n selector where n is the setting number you want to recall The Recall Setting pop up menu also provides a way io initialize the CSA 803A The Initialize Setting selector operates the same as the Utility1 major menu Initialize selector Initialization is described completely on page 3 113 Figure 3 82 The Recall Setting Pop up Menu 3 177 Stored Settings Deleting Stored Use the Delete Setting pop up menu in the Store Recail major menu to Seitin gs delete a stored setting Select the se
356. udes the number of power on cycies the uptime count all stored settings all stored traces and the instrument serial number Non volatile RAM settings stored traces and store trace descrip tions lost instrument ID data retained Part of the non volatile RAM was reset to default at power on because the non volatile RAM was corrupted This can reflect an internal problem or the settings can be corrupted by improper commands from a remote computer connected to the GPIB or RS 232 C interfaces Reference trace defaulted to selected trace The reference trace for a prop delay measurement is no longer a valid trace so the reference is now the same trace as the trace being measured For example assume you defined a prop delay measurement on trace 2 using trace 1 as a reference trace If you delete trace 1 then the next time you display the measurements on trace 2 you will see this message E 3 Appendix E Messages Rho scaling failed to find 1 p point Cannot calibrate rho scales if the trace is not triggered or if the portion of the trace to the immediately to the left of the display earlier in time is not a flat trace the voltage reference cannot be determined Time base calibration failed The time base controller detected an acquisition system error You should contact your service person Time base system error The time base controller detected an acquisition system error You should contact your service person
357. uf On w 24 Pin supports the Extended Epson command set for 24 pin dot matrix printers including the Epson LQ500 Epson LQ1000 NEC P6 and NEC P7 These printers typically use the PRINTER Centronics connector Set the configuration switches on your printer as recommended in its manual except set No Auto Line Feed No Auto Carriage Return No Perf Skip and Inbuf On amp Tek 4692 supports the Tektronix 4692 color graphics copier The Tek 4693D may also be used when set to 4692 emulation Full Color Maxi mized by Interpolation and Portrait Mode These printers typically use the PRINTER Centronics connector w Tek 4696 supporis the Tektronix 4696 and 4695 color inkjet plotters These printers typically use the PRINTER Centronics connector m Tek 4697 supports the Tektronix 4697 ColorQuick Ink Jet printer This printer typically uses the PRINTER connector Bitmap Dump provides the ability to acquire the screen data for external processing For exampie you can use this option to send the display data to a computer The format of this information is determined by the Data Format selector Data format is discussed on page 3 94 You will typically want to use the GPIB or RS 232 C connector for this type of transfer Alt Inkjet supports the HP ThinkJet and HP LaserJet printers The ThinkJet should be used in HP graphics mode not Epson emulation mode For the HP ThinkJet either Draft or HiRes screen mode may be used but
358. up to six measurements for each of your traces The readouts of the measurements of the selected trace appear in the Measure major menu The measurements are listed in the table below and on the next page Refer to Appendix D for a detailed discussion of each of these measurements 3 137 Measurements Selector Table 3 10 Measurements Measures Amplitude Measurements Max Min Mid Mean RMS Peak Peak Overshoot Undershoot Amplitude Extinct Ratio Noise Signal to Noise Ratio Maximum amplitude the most positive peak voitage rho value Minimum amplitude the most negative peak voltage rho value Middle amplitude halfway between maximum ampli tude and minimum amplitude Arithmetic mean of all signal points True Root Mean Square voltage The voltage difference between maximum amplitude and minimum amplitude The difference between the maximum amplitude and the topline value expressed as a percentage of the difference between the topline and baseline values The difference between the baseline value and the mini mum amplitude expressed as a percentage of the dif ference between the topline and baseline values The difference between the topline and baseline values Extinction ratio can be measured using three methods The default method is for extinct equai to be the topline value divided by the baseline value Using the Measure ments pop up you can set this measurement equal to F
359. us are similar and the illustration on the next page of the Offset pop up menu is typical of these menus When you use these pop up menus you first select the sampling head channel you want to calibrate The left side of the pop up menu is reserved for this The Selected Channel line at the top of this section shows which channel is currently selected You can use the selectors in this section to change the selected channel See Figure 3 24 Many of the calibration controls on the right of the pop up menu are com mon to ail five of the pop up menus All these common selectors operate similarly and give you the same options for each calibration Each of the calibrations can be made manually or automatically In addition you can set the calibration to the factory default or to be the same as a calibration you made earlier 3 54 Reference Enhanced Accuracy Uffset Calibration i thennel Fl Offset Nall epee litiiretye Menu i Moin i Figure 3 24 A Typical Calibration Pop up Menu z To calibrate automatically touch the Automatic Calibrate selector A message will tell you to either connect the CALIBRATOR output to the sampling head channel you are calibrating or to attach a terminator to the sampling head channel you are calibrating For most sampling heads a 50 Q terminator is appropriate Refer to the Installation User manual for the sampling head When you have done as directed touch the P
360. ut sampled data point T time interval between successive samples R record length in points Logarithm Log n log Wn where n index into record of data points W n input sampled data point This function is implemented by the 80287 math coprocessor and support ing routines CSA 803A User Manual D 7 Appendix D Aigorithms D 8 Natural Logarithm Lnn log W n where n index into record of data points W n input sampled data point This function is implemented by the 80287 math coprocessor and support ing routines Rho Rho is normally calculated to be between 1 and 1 by For trace M1 volts rho RA x pol wa rhopos _ Ref Voltage rhopos RA x pol 1 rhozero where RA Reference Amplitude normally 250 mV where the reference amplitude is equivalent to the change in volts that corresponds to a change of 1 in rho pol 1 if M1 has positive polarity 1 if M1 has negative polarity volts the voltage at any point in M1 Ref Voltage the voltage of M1 measured as early in time as possible Baseline correction keeps remeasuring the reference voltage and will force a recalculation of rhopos any time it changes by more than a few millivolts rhozero 0 by default The cursor feature Set Zero Rho sets this value For trace M1 M2 where M1 has positive polarity and M2 has negative polarity rhopos 5 RhoPos of M1 ee rhozero rhopos Ref Voltage M
361. ver the power is turned on s Self Test Diagnostics are a subset of the extended diagnostics and are executed as a group at power on You can also execute this group at any time This group of tests takes about 15 seconds to execute m Extended Diagnostics are a complete set of tests which you can exe cute either individually or as a group at any time A separate menu system controls the extended diagnostics Any time the self test diag nostics encounter a failure the extended diagnostics menu remains on the screen so that you are notified of the failure The extended diagnostics menu is primarily intended as an aid for those servicing the instrument This manual introduces the menu but does not discuss the extended diagnostics compietely For complete information see the CSA 803A Service Manual NOTE Do not touch the touch screen or press the front panel buttons during any diagnostic tests You may cause the diagnostics to report spurious failures CSA 803A User Manual 3 35 Diagnostics Power On Diagnostics The CSA 803A executes the power on diagnostics whenever you turn the power on this is the only time these tests are executed The power on diagnostics test the most fundamental operations of the microprocessors and the communication paths between microprocessors Power on diagnostics take about 5 seconds to execute During this time the front panel lights will blink and the display will show the following message if the
362. verted negative pulses but only if Time Base Cal Mode is set to Fast and not High Prec Standard mask autoset will produce errors for more complicated trace expressions Autoset Setting the Stan Mask Offset Adj selector to On causes the instrument to adjust the vertical offset during a standard mask autoset to make the wave form match the selected standard mask more closely Setting this selector to Off turns off vertical offset adjustments during a standard mask autoset This feature only applies to19 of the standard masks They are w CCITT G 703 Standard Masks Single Pulse 64 kb s Double Pulse 64 kb s Data Pulse 64 kb s Timing Pulse 64 kb s Pulse 1 544 Mb s Sym Pair 2 048 Mb s Coax Pair 2 048 Mb s Sym Pair 6 312 Mb s Coax Pair 6 312 Mb s Pulse 8 448 Mb s Pulse 32 064 Mb s Puise 34 368 Mb s Pulse 44 736 Mb s Pulse 97 728 Mb s m ANSI 71 102 Standard Masks Digital Signal 1 DS1 1 544 Mb s Digital Signal 1 DS1 old 1 544 Mb s Digital Signal 1C DS1C 3 152 Mb s Digital Signal 2 DS2 6 312 Mb s Digital Signal 3 DS3 44 736 Mb s For ail other standard masks vertical offset is always adjusted by the stan dard mask autoset regardless of how this option is set in the Instrument Options pop up menu 3 12 l Reference Averaging and Enveloping The averaging and enveloping functions allow you to examine and manage noisy signals m Averaging reduces the apparent noise of a displayed trace and provides a cleaner display The
363. waveform perform a period mea surement 2 Calculate the pulse width of the selected waveform perform a width measurement 3 If the positive portion of the part of the waveform measured for the Period measurement lies between the first two mesial crossings in the measurement zone then 100 x Width Duty Cycle Period If the positive portion of the part of the waveform measured for the Period measurement lies between the second and third mesial cross ings in the measurement zone then Duty Cycle 100 100 2 Width Period Energy Energy A xT jem where m index of left most measurement zone sample n index of right most measurement zone sample WG input sampled data point T time interval between successive samples Extinction Ratio topline Standard Extinction Ratio baseline no units FDDI Extinction Ratio 100 x baseline units topline topline SONET Extinction Ratio 10 x oga jee dB units Appendices Appendix D Algorithms Fail 1 Find the first point in the measurement zone that is greater than the distal value searching from left to right 2 From this point find the first distal crossing and note the time t4 3 From the distal crossing examine points to the right looking for the proximal crossing f Update if subsequent distal crossings are found 4 Calculate the fall time Fall t t Linear interpolation between vertical points an
364. were in effect when the major menu was active last NOTE Always glance at the knob labels before using the knobs When you turn the knobs you wil feel clicks instead of smooth motion Each click represents a minimum change the CSA 803A counts clicks to measure knob motion Depending on the value the knobs are assigned to each click changes the value by some linear increment a multiplicative factor or the next number in a 1 2 5 sequence Operating Basics Icons CSA 803A User Manual Example 1 Displaying a Trace E Step 13 Turn each knob left and right observing the trace changes When you are done restore the trace to its originai appearance by turning the knobs or by pressing the AUTOSET button above the sam pling heads To control the vertical size and offset of a trace you need to reassign the knobs You will use an icon to do this Above and to the teft of the graticule are several icons as shown in Figure 2 10 These icons are always availabie on the display regardiess of which major menu is being shown The trigger icon 7 the vertical icon and the horizontal icon gt assign the knobs Since the current knob assign meni is horizontal main size and position the horizontal icon lt gt is highlighted NOTE The trigger icon is presently unselectable because you cannot adjust the internal trigger level Touching the vertical icon changes the knob assignments as shown in the Kno
365. y sek wee cased Terms in Manuals Ce ed ee eS 2 a s Terms on CQUIDMENE 6oc ator et a oe ee enca med elena Symbols in Manuals lt 5 is oot ces ne whus esa pentane wows Symbols on Equipment lt s c4 sais Vo dope e eosin de wou Power Source ee s Grounding the GSA 803A aic2ceeieckads iekedode bee need Use the Proper Fuse 252 9 9 cu cua ak sea Cues oe sw velo ade Sa Do Not Operate in Explosive Atmospheres Do Not Remove Covers or Panels 0 00 eee eee Electrical Connections ccc ssiwesd ceewceceweesinecdinnieys SMA Compatible and Other Precision Connectors Electrostatic Discharge vos ces tyes SecSGuwawee sao eaees Front Panel Rear Panel Instaliation Ata Glance aeeetrea eae eee eT eT he Oh he he Th Re sttet eaten weer ene ee te hee ee Front Panel and Sampling Heads 0000005 Rear Panel soft e eae oe eee eee ah he OO TH MAY Display and Touch Panel 0 0eeceeee ee eeeeees ICONS cccesewsawesa ee eg Knobs Knob Menu and Keypad Menu 0 ceceeeen Major Menu Buttons ae et DM KKH ree ree a eel Waveform Major Menu ccc ere reer erence enn eunenens Trigger Major Menu Measure Major Menu 0 0ccce ccc ee ene ence ee ea eeees Display Modes Major Menu 00 c cece cence Store Recall Major Menu 500 cen een n ence teen eeeee Utility Major Menu wee Dn ee
366. y two mode selected CSA 803A User Manual B 3 Appendix B Specifications Table B 4 CSA 803A Trigger Specifications Characteristic Jitter Trigger source Trigger mode Auto Normal Maximum p p trigger input Direct Prescaler Maximum safe trigger input voltage Direct Prescaler Trigger level Trigger level resolution Trigger accuracy Trigger sensitivity Direct DC coupled Prescaler AC coupled Metastability Specification 1 3 ps RMS 4 ppm of position typical 2 0 ps RMS 5 ppm of position max Freq 2 5 GHz Vin 200 MV p p HF Off Enhanced On May require trigger level adjustment to avoid 250 ps pulse width when triggering on trailing edge External Direct Internal Clock or External Prescaler Free runs after 20 ms timeout Acquisition only after trigger event 1V p p 2 5 V pp 1 5V 2 5 V 1 Vto 1V 1 mV 10 of full scale 100 mV DC to 3 GHz Auto Enhanced Off Auto holdoff HF Off May require trigger level adjustment to avoid 250 ps pulse width when triggering on trailing edge for stable triggering 600 mV typical peak peak from 2 GHz to 8 GHz Less then 2 V from 8 GHz to 10 GHz Typically 0 ppm tested with 250 K trigger events at 2 5 GHz 100 MVp p trigger Enhanced On Appendices Appendix B Specifications Table B 4 CSA 803A Trigger Specifications Cont Characteristic Specification Main and window position Minimum 23 ns pre trigg
367. ystem speed Touch the Time Base Cal Mode selector of the Enhanced Accuracy major menu to display the pop up menu Note that Off and Once turn off automatic calibration thus if the instrument is left in either mode it can drift out of specification The instrument should be left in Fast or High Prec mode for normal opera tion Setting Fast High Prec Off Once Benefit Increases system throughput slightly Increases accuracy slightly Increases system through put Forces the instrument to per form one complete pass of the time base and vertical calibration then return to the OFF state This single calibration will be a Fast calibration if the pre vious Time Base Cal Mode setting was Fast High Preci sion if the previous setting was High Prec Table 3 2 Time Base Cal Mode Comparison Side Effects Reduces accuracy slightly Slows system throughput slightly System can drift out of speci fication if left in this mode Generally used in OFF state to force calibration The CSA 803A periodicaily compensates the sampling head delay adjust ments without your intervention This maintains the accuracy of the delay adjustment calibrations you have performed earlier You can specify whether or not you want the CSA 803A to perform this automatic compensation Touch the Delay Compensate selector in the Delay Adjust pop up menu to set this parameter to either On or Off Setting Off On Benefit

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