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DPOJET Jitter and Eye Diagram Analysis Tools

1. 2 Technical SUPPOMt Hx E E EE E EE EER EER RE 3 Customer Feedback ec i EE ESEE EER 3 Getting Started Product Description seereis an nonni ne EEE AAE EEE NEEN EA EEEE EEE EE E E EEEE E 5 DPOJET Option Levels necces rrr rot O EE DURAN EE E S ERR NE 5 nici EE EE EEE E NEEE EA EE EEE AERES 6 Requirements and Restrictions 0 ccc cece eee nnn nnn Ee EEEE sse nennen 7 Supported Probes e tees ERR Ed sana echa pM UH ea iene bebhadiunaabiadane chilies aawdan eds 7 Installing the Applicaton occus eto edt e nee qURO DpRR UNO QUE ese aa OD PUep d DEP Fee EG Ets 8 Po ndbluolljg EEUU 9 Operating Basics About Basic Operations Starting the Application ucieeeoeeoe oed eed eduse D ee pDI I ee breve xdv enop N E e ANNEN 11 Application Interface Menu Controls sssssssssssssssssssssse eee eese nens 11 Virtual Keypad cese ec ettet a ree deum UP ORE RR ETENA be S e a VIEN COLOR Ra ag 11 Tips on DPOJET User Interfaces iiron rnEeE eese me s eese esee enn 12 Basic Oscilloscope Functions Application Directories 4 2 eere pede Eoo E E Hep AERA SERES STU Ted STIS UM REC TUE qns 13 File Name EXtensions cee Teese eor eta deme een RAE e cant E ET RR SE EATER RN Eden 13 Application Menu Shortcuts 0c cece cece eee sese se eese hee nens 14 Returning to the Application ssssssssssssssssssssse ee eme ee eese eese enn 14 Saving and Recalling Setups SENA 15 Recalling a Saved Setup i eere ales re
2. 0 ccc ccc cece eee ene eee nen nee mesh messe ee nene 167 Bathtub Plot Parameters 00 ccc cece cence nnn nen me mesh eme se ere nnn 167 Transfer Function Plot Parameters c cece cece eee cence een eee eee meses 167 REPOTIS EEUU 168 Reference Progress Bar Status Messages 0ccce cece Eire E nnn eme ese e e esee ehe e nee 169 DPOJET Jitter and Eye Diagram Analysis Tools V Table of Contents Error C de UU 170 Measurement Values eese ertet rteeeste En E E E EEEE p Segre a bU E NAAG 172 Algorithms About Algorithms is 22 222 0ccaeneedeneas ded ete IS YE EE E O E EF ROETE EEEE ig teen 175 Period Freq Measurements uod MEET 175 Positive and Negative Width 22 2 0 00 cece cece cece eee nee nen eee seme ese mee eren 176 Fregen Gy 176 Dub 177 Positive and Negative Duty Cycle 0 cece cece een ene ee ee eee mene eee 178 602 JT P 178 Positive and Negative CC Duty esce bees tee pure er ES UL E ipe EIS ORE ECL ES E pnA 179 Jitter Measurements TIE gr EE 179 a M 180 Dual Dirac Random Jitter iiie ree n Preside a rene Eee ren uenis ree a e red 180 Jitter Summary M m 180 TIQBER EET 181 DID 181 Dual Dirac Deterministic Jitter sssssssssssssesssssseesssees eese meme mense eese 181 lutte ce
3. E2002 All the refs are used as sources by the measurements Export to Ref is not possible E2003 Ref x is already used as a measurement source E2004 E2005 Ref x is already used as a destination for other measurement No measurement s are selected Export to Ref is not possible E2006 No results available to export to ref E2007 There are no time trend results for the selected measurement s E2008 No ref destination is selected Results will not be exported to ref E3001 Could not open or create a log file Please ensure that you have read write permission to access log folders and files E3002 The specified path is invalid for example The specified path is not mapped to a drive E3003 The specified path file name or both exceed the system defined length For Example On Windows based platforms the path name must be less than 248 characters and file names less than 260 characters DPOJET Jitter and Eye Diagram Analysis Tools 171 Reference Measurement Values Code Description E3004 The specified path directory is read only or is not empty E3005 Please ensure that the file is currently not in use by other process and or has not exceeded the file size limit E3006 Invalid filename Check whether the file name contains a colon in the middle of the string E3007 Select at least one measurement from the table before
4. M 181 jl DUET 182 ID D A E E 182 DECDozssseisae serier Eei E E T EE E AEE 182 Timing Measurements INRCMUUICEEUULMST 183 Heb D 183 Ne EET 184 High TMe p T 184 LOW Mb ER 184 sn 185 FONG UT 185 Eye lx Ahi m 186 Width BER eM 186 siue iieri tito ona E E E OT E E O E EG 186 VEL dIl c oee E A EEEE EEE EE EAAS EE 187 Amplitude Measurements rU E A T 188 LOW M 188 Common Mode ai o er RU d OH TOL E WU E UU LAN EE RHET EID EOEKERI IE seen 189 vi DPOJET Jitter and Eye Diagram Analysis Tools Table of Contents Tn T Ratio sese roa ntt ee ER iN ee EU e vent eoa rax LENT OR E TE Vr Re D du dw A eodein 189 lube T 190 NV DI X OVE EEUU 191 Standard Measurements DDR Setup and Hold Measurements ccccee cece ence ence resres ene mese mese 191 IBN UMP 196 I e nn dbi 197 DDR Hold SE 2 ase ert ERE E FIR re RENTRER EE Cee hoe e eaves Mand ent es Extr NE RENS 197 DDR Hold Diff ccs 4 etre oo etr RR eER Tete tie aad shrig as Paesi ve x ne bhi ce aio ad D RE HET 198 DDR tCL aV8 esien erana E sv annaines ane EEEE E NE AEE E EEEE E EEAS EAEN 198 Ipse Cic ERE 199 DDR tERR n and DDR tERR m n cccceR eee Ree EEEE EEEE EEE AE erri 199 DDR JI T duty ern mt RR FREE AS thats
5. Signal amplitude is extremely low for Math NOTE The error or warning log is saved as DPOJETErrors log in C TekApplications DPOJET subfolder Navigation Panel The Navigation Panel appears on the left of the application window It consists of the following tabs Select Configure Results Plots and Reports 60 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 27 Navigation panel functions Control Panel Tab Description Select Displays the various measurements available for selection By default this tab is highlighted You can click any measurement categorized with Period Freq Jitter Time Eye and Amplitude tabs Configure Displays the configuration for the selected measurement Results Displays the result for the selected measurement Plots Displays the result as a two dimensional plot for additional measurement analysis You can select and configure plots for selected measurements Reports Displays the configuration for generating reports in mht format Allows you to select results plots and details Control Panel The Control Panel appears on the right ofthe application window Using this panel you can start or stop the sequence of processes for the application and the oscilloscope to acquire information from the waveform The controls are Clear Recalc Single and Run The following table describes each of these controls DPOJET Jitter and Eye Diagram Analysis To
6. 118 SEQUENCING us EE 119 Results as Statistics Viewing Statistical Results 3 Ag Er se OAR eS TE ed er eda ae 120 Export Results to Ref Waveform 0 0 0 ccc cece ence een ee eme eene ta 123 Plots R sults as Plots aote hoe ERO ES BL Dee bU EE ae RU eU erre e E 124 Plot Usageutczs esie eI ERU ES E RUE ieee a Ced RI TEE REIR uhi 126 Selecting Plots c E 129 Configuring Plots About Configuring Plots ins recte rr RSV es yep rebar R udya 130 Configuring a Bathtub Plot ssssssssssssssssssssssssssse mee ene 131 Configuring a Spectrum Plot 00 cece cece cece eee eee eee 132 Configuring a Time Trender 222 esi aun ERR E ANE EROR TARTE vedere E dd 132 Configuring a Histogram Plot 0 ccce cece cee eee nee een eme eene 133 Configuring a Transfer Plot 0 0 0 0 0 cece ccc ence eee nen n nnn nn natn nee nES 134 Configuring a Phase Noise Plot cc ccc cece cence nee e ener 136 Configuring an Eye Diagram Plot for Eye Height esee 136 Configuring an Eye Diagram for Mask Hits sess 137 Viewing Plots About Viewing Plots esssssssssssssssessssssee eee ee hee e eene 139 Using a Second Monitor to View Plots cccceecee ence ene e eee eee eme 139 Toolbar Functions in Plot Windows esses 139 Moving and Resizing plots 0 cece cece cee eee nen ee eese mee 140 Using Zoom in a Plot ecce e doe neasea ss AR EARS Ee ENERO NO br be ode 140 Using
7. The Parameters topics for range of values minimum units and default values of parameters B The programmer information in the online help of your oscilloscope Argument Types The syntax shows the format that the instrument returns in response to a query This is also the preferred format when sending the command to the instrument though any of the formats will be accepted This documentation represents these arguments as follows DPOJET Jitter and Eye Diagram Analysis Tools 211 GPIB Commands DPOJET ADDMeas Table 68 Argument types Symbol Meaning lt NR1 gt Signed integer value lt NR2 gt Floating point value without an exponent lt NR3 gt Floating point value with an exponent DPOJET ADDMeas This set only parameter adds the specified measurement to the bottom of the current DPOJET list of measurements and will appear in the results summary page Syntax DPOJET ADDmeas PERIod CCPeriod FREQuency NPERiod PwIdth NwIdth PDUTy NDUTy PCCDuty NCCDuty TIE RJ RJDirac TJber DJ DIDirac PHASENOise DCD DDJ PJ RISEtime SETup HIGHTime FALLtime HOLD LOWTime SKEW HEIght wIDth MASKHits WIDTHBer COMmonmode HIGH TNTratio HIGHLOW LOW VDIFFxovr DDRSETUPSe DDRSETUPDiff DDRHOLDSe DDRHOLDDiff DDRTCLaverage DDRTJITDuty DDRTCKaverage DDRTERrn DDRTJITper DDRTCHaverage DDRTERRMN PCIETTXDIFFPP PCIETNTRATIO PCIETTXA PCIETTXRISE PCIETT
8. Item Description Clock Source Select Ch1 to Ch4 Ref1 to Ref4 or Math to Math4 as reference source for clock recovery Clock Edge Specify whether the rising falling or both edges of selected source should be considered Clock Multiplier Specify the number of edges to be used Apply to All Apply Applies the current clock recovery configuration to all selected measurement s that have Clock Recovery as configuration tab Advanced Displays the Advanced Explicit Clock Edge see page 101 dialog wherein you can adjust the timing relation between reference clock source and data source DPOJET Jitter and Eye Diagram Analysis Tools 101 Operating Basics Advanced Explicit Clock Edge Advanced Explicit Clock Edge To compare the reference clock times to the edge times from the data source some assumptions must be made about how they align The default assumption is that each data source edge is associated with the reference clock edge to which it is nearest in time This assumption may not be optimum for example if the probes for the reference clock and data signal have different cable lengths To change the way the reference clock edges and data edges are associated you can control the Nominal clock Offset Relative to Data The positive or negative time delay you specify will be used to shift the reference clock edges before the measurement software associates each data edge with the closest clock edge Related Topics m
9. Vertical Autoset Failed Measurement error ISDB error code 7 on Source x W1011 A change to Source x vertical settings caused overload disconnect Original settings are restored and Source x is reconnected Ignore oscilloscope message E1012 E1013 Vertical Autoset Failed None of the selected measurements use live sources Ch1 Ch4 Horizontal autoset works for live sources only Vertical Autoset Failed Invalid signal on Source x E1020 Horizontal Autoset Failed None of the selected measurements use live sources Ch1 Ch4 Horizontal autoset works for live sources only E1021 E1022 Horizontal Autoset Failed On Source x cannot determine resolution of rising falling edges Horizontal Autoset Failed Horizontal resolution is at the maximum E1035 E1040 Oscilloscope has gone into invalid state Please restart the system Autoset Failed None of the live sources Ch1 Ch4 selected W1051 Ref Level Autoset Waveform for the source x is clipped W1053 Ref Level Autoset Source amplitude is extremely low E1054 Ref Level Autoset Error in setting reference levels E1055 Ref Level Autoset Failed No waveform to measure E1056 Ref Level Autoset Unstable Histogram for waveform on source x E1057 Ref Level Autoset No selected source E1058 E1059 Ref Level Autoset Failed Invalid signal on source x Ref Level Autoset Error Source x is not defined
10. Autoset Ref Level Autoset RefAuto Refx Reference level autoset for Refx is going on Autoset Ref Level Autoset RefAuto Mathx Reference level autoset for Mathx is going on Sequencing Sequencing Refers to the measurement setup edge extraction Measurement Name Running the measurement specified by name Plots Plotting Plotting is started Bathtub Creating Bathtub plot Spectrum Creating spectrum plot Time Trend Creating time trend plot Histogram Creating Histogram plot Transfer Func Creating Transfer Function plot Eye Mask Hits Creating Eye Diagram plot Eye Height Creating Eye Diagram plot Data Array Creating Data Array plot Phase Noise Creating Phase noise plot Edge Extraction Finding Edges Extracting Edges from signal waveform Clock Data Recovery Recovery Clk Clock and Data recovery Worst case logging Saving WC Wfm Logging the worst case waveform Trigger Slow Trigger Waiting for trigger trigger not available Measurements Name Progress Bar Display Amplitude High Low Ampl High Low Amplitude HighV Amp High Amplitude LowV Ampl Low CMV Common Mode DCD DCD DDJ DDJ DiffXovrV V Diff Xovr DJ DJ DPOJET Jitter and Eye Diagram Analysis Tools 169 Reference Error Codes Function Measurement module Status Message Description DJ66 DJ 6
11. Inputs lt NR3 gt Outputs lt NR3 gt DPOJET Jitter and Eye Diagram Analysis Tools 243 GPIB Commands DPOJET REFLevels CH lt x gt PERcent RISELow DPOJET REFLevels CH lt x gt PERcent RISELow Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH x PERcent RISELOW Inputs NR3 Outputs NR3 DPOJET REFLevels CH lt x gt PERcent FALLHigh Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt PERCent FALLHigh Inputs lt NR3 gt Outputs lt NR3 gt DPOJET REFLevels CH lt x gt PERcent FALLMid Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt PERCent FALLMid 244 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET REFLevels CH lt x gt PERcent FALLLow Inputs lt NR3 gt Outputs lt NR3 gt DPOJET REFLevels CH lt x gt PERcent FALLLow Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt PERCent FALLLow Inputs lt NR3 gt Outputs lt NR3 gt DPOJET REFLevels CH lt x gt PERcent HYSTeresis Sets the hysteresis value used for autoset Syntax DPOJET REFLevels CH x PERcent HYSTeresis Inputs NR3 Outputs NR3 DPOJET Jitter and Eye Diagram Analysis Tools 245 GPIB Commands DPOJET REFLevel CH lt x gt MIDZero DPOJET REFLevel CH lt x gt MIDZero
12. Operating Basics Source Autoset Source Autoset 68 The Source Autoset allows you to automatically adjust the oscilloscope s vertical and or horizontal settings for live sources Ch1 Ch4 to improve measurement accuracy The Vertical Scale option automatically checks the peak to peak level of live sources The vertical scale and offset of all signals with a peak to peak value less than six divisions are adjusted so the peak to peak will be eight divisions If the maximum or minimum value of a signal is clipped the vertical scale and offset are adjusted so that the peak to peak value will be eight divisions The Horizontal Resolution option automatically checks the number of samples edge on the rising and falling transitions Rise Time Resolution and Fall Time Resolution of all live channels The oscilloscope horizontal resolution is set to the largest value that does not cause the samples edge of the fastest edge to fall below the specified target The target is five samples per edge The Horizontal Resolution sets the acquisition sampling mode to Real Time for signals with very high edge speeds The default record length is 500 k points To automatically define both the vertical and horizontal settings for all channel sources select the Vert and Horiz button The Vert and Horiz option also applies an oscilloscope autoset on each channel before performing the vertical scale and horizontal resolution autoset DPOJET Jitter and E
13. Set using DPOJET LIMits FILEName Syntax DPOJET MEAS x RESULts CURRentacq MAXCC STATUS Outputs PASS FAIL DPOJET MEAS lt x gt RESULts CURRentacq MINCC Returns the maximum negative cycle to cycle delta of the selected measurement Syntax DPOJET MEAS x RESULts CURRentacq MINCC Outputs lt NR3 gt DPOJET MEAS lt x gt RESULts CURRentacq MINCC STATus Returns the pass fail status for the min cycle to cycle measurement for the currently loaded limit file Set using DPOJET LIMits FILEName Syntax DPOJET MEAS x RESULts CURRentacq MINCC STATUS Outputs PASS FAIL DPOJET Jitter and Eye Diagram Analysis Tools 251 GPIB Commands DPOJET MEAS lt x gt RESULts ALLAcqs POPUlation DPOJET MEAS lt x gt RESULts ALLAcqs POPUlation Returns the mean measurement value for the currently selected measurement for measurement slot lt x gt Syntax DPOJET MEAS x RESULts ALLACqs POPUlation Outputs lt NR1 gt DPOJET MEAS x RESULts ALLAcqs MEAN Returns the mean value for all accumulated measurement acquisitions for slot x Syntax DPOJET MEAS X RESULtS ALLACQqs MEAN Outputs NR3 DPOJET MEAS lt x gt RESULts ALLAcqs STDev 252 Returns the standard deviation for all accumulated measurement acquisitions for slot lt x gt Syntax DPOJET MEAS x RESULTS ALLACqs STDev Outputs NR3 DPOJET Jitter and Eye Diagram Analy
14. The results tab with error in a text editor Jitter and Eye Diagram Analysis Tools criptio a Std Dev zc fin pp opulation Max cc cC 0 0000s 23 030ps 31 550ps 33 171ps 64 721ps 51 590ps 51 491ps Imo RJ1 Ref1 RJ 601 Ref1 8 DJ 001 Ref1 Phase Noise1 Ref1 44 671ps 0 0000s 44 671ps 44 671ps 0 0000s 8 PJ14 Ref DDJ Ref1 DCD4 Ref oooeocs cjcjecs The results tab with warning A icon is as shown You can click View Log to view the error log information in a text editor Jitter and Eye Diagram Analysis Tools a Std D Mir Populati 0 0000s 8 9609ps 12 680ps 32 428ps 45 108ps 3750 1 5262ps 0 0000s 1 5262ps 1 5262ps 0 0000s 0 0000s 0 0000s 122 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Export Results to Ref Waveform Export Results to Ref Waveform Using this option you can export the time trend plot of a measurement to any of the available reference memory Refl Ref4 Click on the right corner of the results panel to select the Export Results to Ref option The Export Results to Ref waveform dialog box appears It lists all the possible measurements that have time trend result data that is measurements for which time trend plot is enabled in the plot panel From the list of measurements results of any one measurement can be exported to any one of the reference memory Refl Ref4 which is not used as source of any
15. The selected source is validated to have amplitude gt 50 mV When the amplitude of the selected source is gt 50 mV then autoset is performed to increase vertical and horizontal resolution of the signal The selected source is assigned for all single source Jitter measurements The results and plots are generated for a single sequence DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics One Touch Jitter Case 2 Only one source is active The application checks if the active source has amplitude gt 50 mV The selected source is assigned for all single jitter measurements The results and plots are generated for a single sequence Case 3 Two sources are active The application checks whether the active sources are a differential pair Creates a Math waveform taking the difference of the other two Example Math1 Refl Ref2 The lowest numbered Math waveform is considered as the source for all single jitter measurements The results and plots are generated for a single sequence If the active sources are not a differential pair the application checks if one of the source is a clock with a period that divides the other sources An explicit clock recovery method derives the clock from the clock source The application creates explicit clock measurements TIE Height TJ QBER RJ 66 DJ 60 and Width BER for the source The results and plots are generated for a single sequence If one of the active sources is not a clock the appli
16. Turns on or off the mid reference level voltage setting Syntax DPOJET REFLevel CH x MIDZero Inputs 1 0 Outputs 1 0 DPOJET MEAS lt x gt RESULts Returns the measurement branch for the currently selected measurement for measurement slot lt x gt Syntax DPOJET MEAS lt x gt RESULtS DPOJET MEAS lt x gt RESULts CURRentacq POPUlation 246 Returns the population measurement value for the currently selected measurement for measurement slot lt x gt Syntax DPOJET MEAS x RESULts CURRentacq POPUlation Outputs lt NR1 gt DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt RESULts CURRentacq POPUlation STATus DPOJET MEAS lt x gt RESULts CURRentacq POPUlation STATus Returns the pass fail status for the population measurement for the currently loaded limit file Set using DPOJET LIMits FILEName Syntax DPOJET MEAS x RESULts CURRentacq POPUlation STATus Outputs PASS FAIL DPOJET MEAS lt x gt RESULts CURRentacq MEAN Returns the mean measurement for the currently loaded limit file Syntax DPOJET MEAS x RESULts CURRentacq MEAN Outputs NR3 DPOJET MEAS lt x gt RESULts CURRentacq MEAN STATus Returns the pass fail status for the mean measurement for the currently loaded limit file Set using DPOJET LIMits FILEName Syntax DPOJET MEAS x RESULts CURRentacq MEAN STATUS Outputs PASS FAIL DPOJET
17. Zoom and Reset Zoom 140 Zoom in a Plot 140 DPOJET Jitter and Eye Diagram Analysis Tools
18. m P6015 P6101A B P6139A m P6241 m P6243 m P6245 m P6249 m P6150 m P6158 m P7240 m P7260 m P7330 m P7340A m P7350 m P7350SMA m P7360A m P7380A m P7380SMA m P7313A DPOJET Jitter and Eye Diagram Analysis Tools 7 Getting Started Installing the Application m P7313SMA m P7513 Installing the Application Refer to the Optional Applications Software on Windows Based Oscilloscopes Installation Manual for the following information m Software warranty List of available applications compatible oscilloscopes and relevant software and firmware version numbers m Applying a new option installation key label Installing an application Enabling an application Downloading updates from the Tektronix Web site You can find a PDF portable document format file for this document in the Documents directory on the Optional Applications Software on Windows Based Oscilloscopes DVD The DVD booklet contains information on how to install the application from the DVD and on how to apply a new option installation key label 8 DPOJET Jitter and Eye Diagram Analysis Tools Getting Started About DPOJET About DPOJET Click Help gt About DPOJET to view application details such as the release software version number application name and copyright DPOJET Jitter and Eye Diagram Analysis Tools 9 Getting Started About DPOJET 10 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Starti
19. DPOJET INTERp Inputs LINear SINX Outputs LINear SINX DPOJET SOURCEAutoset Performs a DPOJET horizontal vertical or autoset on both horizontal and vertical for any sources used in current measurements Syntax DPOJET SOURCEAutoset Inputs HORIzontal VERTical BOTH DPOJET REFLevels AUTOSet 238 Performs a DPOJET reflevel autoset on any sources selected using DPOJET REFLevels CH lt x gt AUTOSet Syntax DPOJET REFLevels AUTOSet Inputs EXECute NOTE All pieces of the reflevel branch have the ability to set ref levels for CH1 CH4 MATH I MATHA and REFI Ref4 Only the CH lt x gt portion is shown in this OLH but it exists and matches exactly for MATH DPOJET REFLevels MATH x and REF DPOJET REFLevels REF lt x gt DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET REFLevels CH lt x gt AUTOSet DPOJET REFLevels CH lt x gt AUTOSet Sets or clears the reflevel autoset state of the given source When set to 1 the given source will have a ref level autoset done on it during the next acquisition Syntax DPOJET REFLevels CH x AUTOSet Inputs 1 0 Outputs 1 0 NOTE The Ref Level Autoset state is shown only for Ch1 Ch4 sources It is the same for MATH and Ref waveforms For example DPOJET REFLevels MATH x DPOJET REFLevels REF x DPOJET REFLevels CH lt x gt BASETop Sets the base top method for autoset Syntax DPOJET REFLevels CH lt
20. NOMINALOFFset Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt CLOCKRecovery CLOCKMultiplier Sets or queries the clock multiplier Syntax DPOJET MEAS x CLOCKRecovery CLOCKMultiplier Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt BITType Sets or queries the measurement bit type setting Syntax DPOJET MEAS x BITType 228 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt BITPcnt Inputs ALLBits NONTRANsition TRANsitionj Outputs ALLBits NONTRANsition TRANsitionj DPOJET MEAS x BITPcnt Sets or queries the percentage of the center of bit to measure Syntax DPOJET MEAS x BITPcnt Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt BITCfgmethod Sets or queries the measurement bit configure method Inputs MEAN MODE Outputs MEAN MODE DPOJET MEAS lt x gt MASKfile Sets or queries the current mask file name DPOJET Jitter and Eye Diagram Analysis Tools 229 GPIB Commands DPOJET MEAS lt x gt MEASRange STATE Syntax DPOJET MEAS lt x gt MASKfi le Inputs String Outputs String DPOJET MEAS lt x gt MEASRange STATE Turns on or off the measurement range limits Syntax DPOJET MEAS lt x gt MEASRange STATE Inputs 1 0 Outputs 1 0 DPOJET MEAS lt x gt MEASRange MIN 230 Sets or queries the minimum measurement range limit value Syntax DPOJET MEAS x MEASRang
21. each transition between a menu and an option For example Analyze gt Wizard gt One Touch Jitter The terms DPOJET application and application refer to DPOJET The term oscilloscope refers to any product on which this application runs The term DUT is an abbreviation for Device Under Test The term select is a generic term that applies to the methods of choosing an option with a mouse or with the touch screen User interface screen graphics are taken from a DPO7000 series oscilloscope You can find a PDF portable document format file for this document in the Documents directory on the Optional Applications Software on Windows Based Oscilloscopes DVD The DVD booklet only contains information on installing the application from the DVD and on how to apply a new label You can also find the PDF and the Online Help at Start gt Programs gt TekApplications gt DPOJET DPOJET Jitter and Eye Diagram Analysis Tools Introduction to the Application Table 2 Icon descriptions Icon Technical Support Meaning This icon identifies important information A This icon identifies conditions or practices that could result in loss of data This icon identifies additional information that will help you E use the application more efficiently Technical Support Tektronix welcomes your comments about products and services Contact Tektronix through mail telephone or the Web site Click Cont
22. refer to Ref Levels see page 70 5 Click Configure in the left navigation panel to view the configure tabs For more details refer to Configuring Measurements see page 76 6 Click Plots to view the available plots for the selected measurement Select Time Trend and Spectrum plots for TIE measurement For more details refer to Configure Plots see page 130 7 Click Single to run the application When complete the result statistics is shown in the results tab The plots are displayed as follows DPOJET Plots Fol Ma vo TIE1 Spectrum oer ras reer L 1GHz 1 2GHz PERO Ten VITRE eo GO SOT OR PORTS ON 0 2GHz 0 4GHz 0 6GHz 0 8GHz NOTE You can log result statistics see page 37 measurement data points see page 38 to a csv file and worst case waveforms see page 46 to a wfm file Taking an Eye Height and Width Measurement For signal integrity application use the Eye Height and Width measurements 1 Select Analyze gt Jitter and Eye Analysis gt Select to run the DPOJET application 2 Goto Select in the left navigation panel Click Eye tab to select Height and Width measurement In this example Rt EyeTutorial wfm is recalled as Refl and is selected as source for Heightl and Widthl DPOJET Jitter and Eye Diagram Analysis Tools 151 Tutorial Taking an Eye Height and Width Measurement Jitter and Eye Diagram Analysis Tools Measurements Source s Width BER arent 3 Select Re
23. single ended DQS waveform and that of a data waveform based on their respective DDR specific reference level crossings DDR Hold Diff DDR tCK avg Elapsed time between the designated edge of a differential DQS waveform and that of a data waveform based on their respective DDR specific reference level crossings Calculated as the average clock period across a sliding 200 cycle window DDR tCL avg Defined as the average low pulse width calculated across a sliding 200 cycle window of consecutive low pulses 20 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 12 Standard measurements definitions cont Table of Measurements Standard Measurement Description DDR tCH avg Defined as the average high pulse width and is calculated across a sliding 200 cycle window of high pulses DDR tERR n Defined as the cumulative error across multiple consecutive cycles from tCK avg DDR tERR m n Defined as the cumulative error across multiple consecutive predefined cycles from tCK avg DDR tJIT duty Defined as the cumulative set of the largest deviation of any single tCH from tCH avg and the largest deviation of any single tCL from tCL avg DDR tJIT per Defined as the largest deviation of any single tCK from tCK avg PCI Express 2 0 PCle T Tx Diff PP Defined as the change in voltage level across a transition in the waveform PCle T TXA Defined as the measure
24. 46 logging export directory 55 Loop BW 99 Low 20 Low Pass 89 Low Pass filter 87 Low Time 184 Lower Frequency 113 M Main Edge 113 Mask 106 Mask files 13 Mask Hits 187 Max 121 Max or Min value 87 Max cc 121 Mean 121 Measure the Center 106 Measurement Range 87 Measurement Select Parameters 155 measurements 16 Measurements Amplitude 19 Measurements Eye 19 Measurements Jitter 17 Measurements Period Freq 16 Measurements Time 18 Menu Shortcuts Alt A J 14 Method 106 Min 121 Min cc 121 Moving and Resizing plots 140 Moving and Resizing Plots 140 N N Period 16 Navigation Panel 60 Neg Width 16 Noise Integration Limits 113 Nominal Clock Offset 103 Nominal Data Rate 97 Non Transition 107 Notifier Duration 52 Number of Bins 133 Number of Periods 117 O One Touch Jitter 22 Opposite as From 112 Oscilloscope model number 3 P p p 121 Pass or Fail status 56 Path Defaults 55 Pattern File Name 97 Pattern Length 108 Pattern Type 108 PCle 89 PCle Med Mx Jitter 80 PCle T nT Ratio 80 PCle T RF Mismch 80 PCle T Tx Diff PP 80 PCle T Tx Fall 80 PCle T Tx Rise 80 PCle T TXA 80 PCle Tmin Pulse 80 PCle UI 80 Period 16 Phase Noise 126 Phase Noise Plot Parameters 167 PJ 17 PLL Clock Recovery Setup 98 PLL Custom BW 99 PLL Model 99 PLL Standard BW 98 Plot files 13 Plot Summary Views 140 Plot Usage 126 Plots 61 Population 1
25. By default all measurements are selected Select All Selects all the measurements in the list Clear All Deselects all the measurements in the list Log Worst Case Waveforms Off Disables the application to save worst case waveforms for all selected measurements On Enables the application to save worst case waveforms for all selected measurements DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 18 Log Worst Case options cont Data Logging Worst Case Item Description Folder Browse Saves the csv file in the specified directory The default directory is C NTekApplicationsNDPO JET Logs waveforms File Names View Displays View Log File Names see page 47 dialog box which lists the selected measurements with source s and their corresponding log file names in YYMMDD_HHMMSS_ lt MeasurementName gt lt Source s gt _Max lt Source Number gt wfm and lt MeasurementName gt lt Source s gt _Min lt Source Number wfm t format t For example if the selected measurement is Skew1 with Ref1 and Ref3 as sources then the file names will be Skew1 Ref1 Ref3 Max1 wfm Skew1 Ref1 Ref3_Min1 wfm Skew1 Ref1 Ref3 Max2 wfm and Skew1 Ref1 Ref3 Min2 wfm View Log File Names The View Log File Names dialog box lists the selected measurements with source s and their corresponding log file names in YYMMDD HHMMSS MeasurementName Source s Max Source Number gt wfm and Measu
26. C rsors ma Plot rop opea e eoe REM e EE EIN EUH idee ee ia 141 Exporting Plot Files doe e RR EE A i urbia 142 Printing Plots coe etri EAR NER E TR Era ERE e TER t La eec ved 143 Reports About Reports 2i e p EVER TO ind vere ue RE ou re EU EUER IR FERES 143 DPOJET Jitter and Eye Diagram Analysis Tools Table of Contents Tutorial Introduction to the Tutorial 00 cece cece nnn e me ee memes sehen 147 Setting Up the Oscilloscope sssisrro iriri ee ther exe dundevaea een eevee exu He D REA e a RN e xe EUR S 147 Starting the Application iiec LIEST E T CHART H LPs eee OUR MUDU EET E Power ERI ERTRA 147 Waveform Files M LEEEEE UETT 147 Recalling a Waveform File e sccscsanicaaces eee rre cuancavers avenger RR RR Ve p Tea AIRE GA 148 Taking a Period Measurement 00 ccc cece cen cee enn ee eee ee mesh eme sees e n 148 Taking a TIE Measurement nete etre eris reu d reed EEE EEEE EREE ENESE SESA 150 Taking an Eye Height and Width Measurement sss mee 151 Summary T torial PUEDE 153 Stopping the BO VELIS 154 Returning to the Tutorial ilie ce odd dean bes dees taked T ee PER aneeaaeedsaasen dots aad EE ER Yn 154 Parameters About Parameters oe edd Lp RUE OE T TE E EEEE TEE EE 155 Measurement Select Parameters noncer erenn e e E A E EEEE EEE RE E enn 155 Autoset Parameters joc oce ber e EE EE P Rx ENEE EAEE E EE AR EN i Y 155 Ref Level Men Parameters croce eot gat vex et ede Trev bale dae wwielelb
27. CH1 CH4 Outputs CH1 CH4 DPOJET DESKEW DESKEWMidlevel Sets or returns the deskew channel midlevel value Syntax DPOJET DESKEW DESKEWMid level DPOJET Jitter and Eye Diagram Analysis Tools 279 GPIB Commands DPOJET DESKEW DESKEWHysteresis Inputs lt NR3 gt Outputs lt NR3 gt DPOJET DESKEW DESKEWhysteresis Sets or returns the deskew channel hysteresis value Syntax DPOJET DESKEW DESKEWHysteresis Inputs NR3 Outputs NR3 DPOJET DESKEW MAXimum 280 Sets or returns the maximum deskew value possible Syntax DPOJET DESKEW MAX mum Inputs lt NR3 gt Outputs lt NR3 gt DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET DESKEW MINimum Sets or returns the minimum deskew value possible Syntax DPOJET DESKEW MINimum Inputs NR3 Outputs NR3 DPOJET DESKEW EDGE Sets or returns the edge types used when calculating deskew Syntax DPOJET DESKEW EDGE Inputs RISE FALL BOTH Outputs RISE FALL BOTH DPOJET VERsion Returns the current DPOJET version string Syntax DPOJET VERSion DPOJET Jitter and Eye Diagram Analysis Tools DPOJET DESKEW MINimum 281 GPIB Commands DPOJET NUMMeas Outputs String DPOJET NUMMeas Returns the current number of defined measurements Syntax DPOJET NUMMeas Outputs lt NR1 gt DPOJET MEAS lt x gt DDR NPERCycle Sets or returns the
28. Cursors allow you to view numerical values associated with a plot based on cursor locations There are two types of cursors DPOJET Jitter and Eye Diagram Analysis Tools 141 Operating Basics Exporting Plot Files m Horizontal cursors Vertical cursors Table 65 Cursor functions in a plot Item Description g Displays the vertical coordinate where each cursor touches the plot and the difference A between the cursors Vt Displays the horizontal coordinate where each cursor touches the plot and the difference A between the cursors 3 Brings the cursors into the visible part of the plot RESET p Displays the plot properties Cursors in a Plot You can use cursors to read the coordinate where each cursor line touches the plot and also view the difference A between the two cursors The steps to use cursors in a plot details window are 1 Select any of the following cursors iva to use horizontal cursors V to use vertical cursors uh to bring cursors into the visible plot 2 Select and drag either cursor to move the cursor to the desired part of the plot The cursor readout changes to reflect the cursor position NOTE You can drag cursors only when the Zoom functions are disabled TIP If you prefer to move the cursors in the plot window with your finger you can activate the touch screen on the oscilloscope Exporting Plot Files 142 You can export plot image in Plot Toolbar w
29. DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt RESULTS STATus DPOJET MEAS lt x gt RESULTS STATus Returns the status of the given measurement values in slot MEAS lt x gt Valid for currently valid measurements or the error status such as Not enough edges Syntax DPOJET MEAS lt X gt RESULTS STATUS Outputs String DPOJET ADDPIot This set only command creates a plot of the specified type on the specified DPOJET measurement Up to four plots can be created Syntax DPOJET ADDPlot Inputs TIMEtrend DATAarray HISTOgram SPECtrum TRANSfer PHASEnoise EYE WAVEform BATHtub MEAS lt x gt Example DPOJET ADDPlot HISTOgram MEAS2 DPOJET CLEARALLPlots This set only parameter clears the entire current list of defined plots in DPOJET Syntax DPOJET CLEARALLPlots DPOJET Jitter and Eye Diagram Analysis Tools 257 GPIB Commands DPOJET PLOT lt x gt TY Pe Arguments NONE Outputs NONE DPOJET PLOT lt x gt TYPe Returns the current plot type for the selected plot Syntax DPOJET PLOT lt x gt TYPe Outputs TIMEtrend DATAarray HISTOgram SPECtrum TRANSfer PHASEnoise EYE WAVEform BATHtub DPOJET PLOT lt x gt SOUrce Returns the source measurement for the selected plot Syntax DPOJET PLOT lt x gt SOUrce Outputs MEAS1 MEAS99 DPOJET PLOT lt x gt TREND TYPe Sets or returns the trend type setting for
30. Effect of Nominal Clock Offset on Eye Diagrams Explicit Clock PLL Select Explicit Clock PLL as the clock recovery method if you want to feed the edges from the selected clock source through a PLL rather than using them directly The actual edges from the clock source will be used to drive a software PLL model and the edge times coming out of the PLL will be used as the reference edges for the target measurement If the Clock Multiplier is set to a number N other than 1 the output of the PLL will have N edges per actual edge 102 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Advanced Explicit Clock PLL Jitter and Eye Diagram Analysis Tools Explicit Clock PLL ay Clock Edge Clock Recovery Table 53 Explicit Clock PLL options Item Description Clock Source Select Ch1 to Ch4 Ref to Ref4 or Math1 to Math4 as reference source for clock recovery Clock Edge Specify whether the rising falling or both edges of selected source should be considered Clock Multiplier Specify the number of edges to be used Apply to All Apply Applies the current clock recovery configuration to all selected measurement s that have Clock Recovery as configuration tab Advanced Displays the Advanced Explicit Clock PLL see page 103 dialog wherein you can adjust the timing relation between reference clock source and data source Advanced Explicit Clock PLL In the Advanced Explicit Clock PL
31. Error TIE for that waveform If Constant Clock Mean is selected as the clock recovery method both the frequency and the phase are chosen to minimize the mean squared error If Constant Clock Fixed is selected as the clock recovery method the precise frequency specified is used but the phase is chosen so that the median error between the recovered and measured edges is zero DPOJET Jitter and Eye Diagram Analysis Tools 93 Operating Basics Constant Clock Mean If Constant Clock Median is selected as the clock recovery method the phase is chosen so that the median error between the recovered and measured edges is zero CC linear regressram EDGE LLI to C1 LLI aE k WT Indes in tk UI n delay Constant Clock Mean This method provides the following options that control how the clock recovery is performed Auto Calc First Acq Auto Calc Every Acq Selecting Autocalc First Acq will allow the clock recovery algorithm to choose a new best fit clock frequency and phase only on the first acquisition Subsequent acquisitions will choose a best fit on clock phase but retain the clock frequency found on the first acquisition Selecting Autocalc Every Acq will allow the clock recovery algorithm to choose a new best fit clock frequency and phase for each new oscilloscope acquisition Clearing the measurement results by choosing Clear on the sequencing panel will reset the clock recovery so that bo
32. Eye Diagram Analysis Tools GPIB Commands DPOJET EXPORT DPOJET EXPORT This sets only parameter saves the specified DPOJET plot to the specified file path The Format is determined through the filename extension with a default of png should no extension be specified Supported extensions include jpeg jpg tif tiff bmp emf and png For example DPOJET EXPORT PLOTI savedimage tif Syntax DPOJET EXPORT Inputs PLOT1 PLOT4 file string gt DPOJET Jitter and Eye Diagram Analysis Tools 285 GPIB Commands DPOJET EXPORT 286 DPOJET Jitter and Eye Diagram Analysis Tools Index Symbols and Numbers CC Duty 16 Duty Cycle 16 A About DPOJET Help gt About DPOJET 9 Active Edge 113 Advanced Explicit Clock Edge 102 Advanced Explicit Clock PLL 103 Advanced Filter Configuration 90 Advanced Filter Configure Parameters 164 Algorithms 175 All Bits 105 Application Directories installation directory for DPOJET 13 Application Interface Menu Controls 11 Apply to Al 95 Argument Types 211 Armed Disarmed 72 Auto Calc Every Acq 96 Auto Calc First Acq 96 Autocalc Every Acq 94 Autocalc First Acq 94 Autoset 72 Autoset Parameters 155 Autoset Ref Levels 75 B Band Pass 88 Base Top Method 75 Bathtub 126 Bathtub Plot Parameters 167 Bit Config for Amplitude 106 Bit Config for Eye Height 104 Bit Config for Mask Hits 105 Bit Config Parameters 159 blanked 90 blanking duration
33. Freq F1 1 Hz to 1000 GHz 1KHz Low Pass F2 Filter Spec No Filter 1st order 2nd order 3rd order No Filter Freq F2 1 Hz to 1000 GHz 1 KHz Advanced Filter Configure Parameters The Advanced Filter Configuration includes the following parameters Option Parameters Default setting Ramp Time O F to 10 F 2 F Blanking Time O F to 10 F AIF General Parameters The General configure menu has the following parameters Option Parameters Default setting Measurement Range Limits Off On Off Maximum and minimum values vary for different measurements For more details refer to Measurement Values Global Parameters 164 The Global configure menu has the following parameters Option Parameter Default setting Gating Gating Off Zoom Cursors Off Qualify Qualify Off On Off DPOJET Jitter and Eye Diagram Analysis Tools Parameters Global Parameters Option Parameter Default setting Qualify With Logic Source Ch1 Ch4 Ref1 Ref4 Math1 Math4 Ch1 Search1 Search8 Mid 20 V to 20V OV Hysteresis 0 to 10 V 30 mV Active High Low High Population Population Off On Off Population Limit Limits By Population Acquisitions Acquisitions Limit 1 to 2 31 1K Stop Condition Each Measurement Last Each Measurement Measurement DPOJET Jitter and Eye Diagram Analysis Tools 165 Parameters Histogram Plot Parameters Histogram Plot Parameters The Histogram plot has Autoset as the command
34. Includes a 3 dB cut off frequency Brick Wall Filter Configuration Measurements such as PCIe T nT Ratio and PCIe Med Mx Jitter use the Brick Wall filter A brick wall filter is applied to the PCIe signal to remove the low frequency jitter components The PCI Express application applies the filter as per the PCIe specification Brick Wall filter has a very sharp cut off frequency DPOJET Jitter and Eye Diagram Analysis Tools 89 Operating Basics Advanced Filter Configuration Jitter and Eye Diagram Analysis Tools PCle TinT Ratio1 Edges PCle Med Mx Jitter P cht Brick Wall Filter Filters j General Global Advanced Filter Configuration 90 The measurement filters are implemented using infinite impulse response IIR designs As with any causal filter a transient may occur at the filter s output in response to the arrival of the input signal It is usually desirable to exclude this transient from the measurement results In the DPOJET application the filter transient is managed in two ways First the input to the filter is gently ramped up from zero to its full value over some ramp time t Second the output of the ramp is blanked over some duration t so that the remaining effects of any transient are omitted from measurement results statistics and plots The sequence of operations is depicted here Unfiltered Blanking Filtered Measurement ftp Measurement The ramp function has a r
35. MaAx 1S the maximum of the Low non transition bit eye voltage at mid UI Mask Hits The Mask Hits measurement reports the number of unit intervals in the acquisition for which mask hits occurred for a user specified mask In the Results Summary view the Mask Hits measurement reports the total number of unit intervals for which a mask hit occurred in at least one mask zone In the Results Details view the number of hits in each of three segments is reported The population field shows the total number of unit intervals measured The Mask Hits measurement has several unique properties m Unlike other measurements it requires a Mask hits plot Adding a Mask Hits measurement will cause the corresponding plot to be created automatically If you delete a Mask Hits plot the application will remove the corresponding Mask Hits measurement after verifying the action with you B The Mask Hits measurement does not support the Worst Case Waveforms logging feature B The Mask Hits measurement does not support Measurement Range Limits DPOJET Jitter and Eye Diagram Analysis Tools 187 Algorithms High High Low 188 The High Amplitude measurement calculates the mean or mode of a selected portion of each unit interval corresponding to a 1 bit The application calculates this measurement using the following equation Vy n OP v perce n j Where Vy is the high amplitude measurement result OP is the selected Operation eit
36. Min Period Freq measurements Period 1 ms 1 ks 0 ns 0 ns 1 ks 0 ns CC Period 1ns 1s 1 fs 1ns 1 fs 1s Freq 10 GHz 50 GHz 1 MHz 10 KHz 50 GHz 1 MHz N Period 1ms 1 ks 0 ns 0 ns 1 ks 0 ns DPOJET Jitter and Eye Diagram Analysis Tools Reference Measurement Range Limits Max Measurement Range Limits Min Measurement Values Pos Width 10 ns 1 Ms 1 ps 1 ns 1 Ms 1 ps Neg Width Duty 90 96 100 96 0 96 10 96 100 96 0 96 Cycle Duty Cycle CC Duty 1 ns 1 ks 1ks 1ns 1 ks 1ks CC Duty Jitter Measurements TIE 1 ns 1 us 1 us 1ns 1 us 1 us RJ 1 ns 1 us 0 ns 1 ns 1 us 0 ns RJ 66 1 ns 1 us 0 ns 0 ns 1 us 0 ns TJ 1 ns 1 us 0 ns 0 ns 1 us 0 ns DJ 1 ns 1 us 0 ns 0 ns 1 us 0 ns DJ 66 1 ns 1 us 0 ns 0 ns 1 us 0 ns Phase Noise 1ms 1ms 0s 0s 1ms 0s DCD 1 ns 1 us 0 ns 0 ns 1 us 0 ns DDJ 1 ns 1 us 0 ns 0 ns 1 us 0 ns PJ 1 ns 1 us 0 ns 0 ns 1 us 0 ns Time Measurements Rise Time 200 ns 1 ks 0 ns 0s 1 ks 0 ns Setup 10 ns 1s 1s 0 ns 1s 1s High Time 10 ns 1 Ms 1 ps 0s 1 Ms 1 ps Fall Time 200 ns 1 ks 0 ns 0s 1 ks 0 ns Hold 10 ns 1s 1s 0 ns 1s 1s Low Time 10 ns 1 Ms 1 ps 0s 1 Ms 1 ps Skew 10 ns 1s 1s 10 ns 1s 1s Eye Measurements Height 500 mV 1 kV 0 mV 50 mV 1 kV 0 mV Width 1 ns 1s 0 ps 50 ps 1s 0 ps Mask Hits 500 Hits 1 MHits 0 Hits 0 Hits 1 MHits 0 Hits Width BER 0 9 Ul 1 0 Ul 0 UI 0 1 UI 1 0 UI 0 UI Amplitude Measurements Commo
37. Outputs NR3 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt RESULts ALLAcqs SEG lt x gt MA XHits DPOJET MEAS lt x gt RESULts ALLAcqs SEG lt x gt MAXHits Returns the maximum mask hits measurement for the given segment either SEG1 SEG2 or SEG3 Syntax DPOJET MEAS x RESULtS ALLACQS SEG x MAXHits Outputs NR3 DPOJET MEAS lt x gt RESULts ALLAcqs SEG lt x gt Hits Returns the mask hits measurement for the given segment either SEG1 SEG2 or SEG3 Syntax DPOJET MEAS x RESULtS ALLACQS SEG lt x gt Hits Outputs NR3 DPOJET MEAS lt x gt RESULts ALLAcqs MINHits Returns the minimum mask hits measurement for all segments Syntax DPOJET MEAS x RESULtS ALLACQS MINHi ts Outputs NR3 DPOJET Jitter and Eye Diagram Analysis Tools 255 GPIB Commands DPOJET MEAS lt x gt RESULts ALLAcqs MA XHits DPOJET MEAS x RESULts ALLAcqs MAXHits Returns the maximum mask hits measurement for all segments Syntax DPOJET MEAS x RESULtS ALLACQS MAXHi ts Outputs NR3 DPOJET MEAS lt x gt RESULts ALLAcqs HITS Returns the mask hits measurement for all segments Syntax DPOJET MEAS x RESULtS ALLACqs HITS Outputs NR3 DPOJET MEAS lt x gt RESULts ALLAcqs HITPopulation 256 Returns the mask hit population Syntax DPOJET MEAS x RESULts ALLACqs HITPopulation Outputs NR3
38. PARAR RR Eee X SE RISE EUER leeds none SE GIO RU EUR eda 200 DDR HR EL 200 DDR 1CH AaV ES cscs chatdicadin a hachaaaeeaboninmacdabiald sada bb kattee dpud ecn x Ux bb ui dove soit eio ils 200 PCle T Tx Ditte PP vii EUER 201 POl THT XA C 201 lue T T Fal pem 202 le TminPulse P a a E E a EE aN aaa 202 PCIe atiiBiCcobpP 203 PCle T TX Ribe rS 203 PCIe Ul ers a a a a E E NE E AE 204 PCIe Med MX Jittet riasenie eaa EEA E EEA E EE ENEE EEES 204 PCle T RF Mismeh i562 estes LETS 204 Jitter Separation Jitter Analysis Through RJ DJ Separation cssssssssssssssssssse me menm 205 RJ DJ Separation via Spectrum Analysis sess me me ene 205 RJ DJ Separation for Arbitrary Patterns 0 ccc cece ence eee ence eee eme eme mene 206 Estimation of T BER and Eye Width QBER sss 206 Jitter Estimation Using Dual Dirac Models 0c cece ese e cece ne eee cent ene mene 207 lip MEET 207 GPIB Commands About the GPIB Program 23 rr oi rr Oe Er e PUE VERD Sees ea VES Tear E ede 211 GPIB Reference Materials etre e eoe xe ene ERAS T Ee LEX REA a aua s e etas 211 ATOUMENE TYPES PEE 211 DPOJET ADDME S oriris iesise meiit iei E ce E E band seule wens dradeeaebardeenanieegteansenebiedes 212 DPOJET CLEARALLMIGS notte rere eee x pen EX SEE Fedex Free dba e eee e du eens 212 DPOJEESTALE eerte eee deepestenuedibbessatexe Robe ntu DO P receperit uxb opo tu
39. PJ DDJ DCD RJ 66 DJ 66 TJ BER Jitter Summary and Phase Noise m Time Rise Time Fall Time High Time Low Time Setup Hold and Skew B Eye Height Width Mask Hits and Width BER Ampl High Low Common Mode High Low T nT Ratio and V Diff Xovr B Standard DDR Setup SE DDR Setup Diff DDR Hold SE DDR Hold Diff DDR tCK avg DDR tCH avg DDR tCL avg DDR tERR n DDR tERR m n DDR tJIT duty DDR tJIT per PCIe T Tx Diff PP PCIe T TXA PCIe T Tx Fall PCIe Tmin Pulse PCIe T nT Ratio PCIe T Tx Rise PCIe UI PCIe Med Mx Jitter and PCIe T RF Mismch You can set the Source option as any of the following waveforms Chl Ch2 Ch3 Ch4 Refl Ref2 Ref3 Ref4 Mathl1 Math2 Math3 or Math4 Table 67 Source parameters Option Parameters Default Source Ch1 Ch4 Math1 Math4 Ref1 Ref4 Ch1 Source2 Ch1 Ch4 Math1 Math4 Ref1 Ref4 Ch2 Autoset Parameters The Configure Source Autoset includes the following command buttons B Vert Scale DPOJET Jitter and Eye Diagram Analysis Tools 155 Parameters m Horiz Res B Vert amp Horiz Undo Ref Level Menu Parameters 156 Ref Level Menu Parameters The Configure Ref Level menu parameters includes the following command buttons Autoset Setup Option Parameters Default setting Source Ch1 Ch4 Ref1 Ref4 Math1 Math4 Autoset Set Clear Set Rise High 20 V to 20 V 1V Rise Mid 20 V to 20 V OV Rise Low
40. Recov UI Name Measurements Config Edges ery RJDJ Filters General Global TIE Clock TIE nw nw a a p Data TIE a a y yw TJ BER Clock TJ yw w a a a a Data TJ a a a wv nw DCD Clock DCD a a a i a a Data DCD v w a a a RJ Clock RJ nw a a a a a Data RJ yw y y a iw DJ Clock DJ a iY a a a Yn Data DJ w w a a J DDJ DDJ Pl a a nv a a DPOJET Jitter and Eye Diagram Analysis Tools TT Operating Basics About Configuring a Measurement Table 34 Jitter measurements cont Clock Bit Recov UI Name Measurements Config Edges ery RJDJ Filters General Global RJ 66 Clock RJ 566 a a w w In w Data RJ 66 a a a a w DJ 66 Clock DJ 56 Val w w w w w Data DJ 66 Ll v nw w al PJ Clock PJ al al a Val al al Data PJ a a a a nw Jitter Sum mary 1 Phase al w Val w Noise 1 Jitter Summary is not an individual measurement but a convenience function Pressing this button automatically adds a set of eleven jitter related measurements with a single action The measurements are TIE RJ RJ 55 DJ DJ 55 PJ DDJ DCD TJ BER Width BER and Phase Noise Table 35 Timing measurements Clock Bit Recov Measurements Config Edges ery RJDJ Filters General Global Rise Time nw nw a y Fall Time De y a nw Skew a a a a High Time nw nw a Low Time a a Yn Setup v a Dd w Hold a a a a Table 36 Eye measurements Clock Bit Recov Measurements Config Edges ery RJDJ Filters General Global Width w a a Width BER Va
41. Span is divided 25 50 100 250 or 500 Horizontal Scale Auto Scale Causes the horizontal scale of the histogram to be adjusted automatically based on the accumulated data points If subsequently acquired data falls outside the current horizontal scale histogram bins are consolidated so that the number of bins is preserved and the horizontal scale allows all data to be plotted When checked disables the Center and Span numerical inputs Center Manually sets the value for the horizontal center of the Histogram for subsequent plot updates Span Manually sets the value for the total horizontal range of the Histogram for subsequent plot updates Autoset Uses the results of the latest acquisition to determine the logical values for the Center and Span options if the population of the measurement is three or more OK Accepts the changes and closes the window Configuring a Transfer Plot 134 Select a Transfer Function plot in the table on the right and click Configure to configure the plot PeerRen m Average Item Description Definition Numerator Measurement for which the magnitude spectrum is used as Denominator a reference Measurement for which the magnitude spectrum is used to normalize the numerator DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Configuring a Transfer Plot Item Description Vertical Scale L
42. Trend plots 258 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET PLOT lt x gt HISTOgram AUTOset Syntax DPOJET PLOT x TREND TYPe Inputs VECTOR BAR Outputs VECTOR BAR DPOJET PLOT lt x gt HISTOgram AUTOset Runs a histogram autoset for the specified slot Syntax DPOJET PLOT x HISTOgram AUTOset Inputs EXECute NOTE Undefined for non histogram plots DPOJET PLOT lt x gt HISTOgram VERTical SCALE Sets or returns the vertical scale setting for applicable plots either Linear or Log Syntax DPOJET PLOT x HISTOgram VERTical SCALE Inputs LINEAR LOG DPOJET Jitter and Eye Diagram Analysis Tools 259 GPIB Commands DPOJET PLOT lt x gt HISTOgram HORizontal AUTOscale Outputs LINEAR LOG NOTE Undefined for non histogram plots DPOJET PLOT lt x gt HISTOgram HORizontal AUTOscale Sets or returns the horizontal auto scale settings Syntax DPOJET PLOT lt x gt HISTOgram HORi zontal AUTOscale Inputs 1 0 Outputs 1 0 NOTE Undefined for non histogram plots DPOJET PLOT lt x gt HISTOgram HORizontal RESolution Sets or returns the horizontal resolution used in Eye Diagram plots Syntax DPOJET PLOT lt x gt HISTOgram HORi zontal RESolution Inputs lt NR3 gt Outputs lt NR3 gt 260 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET PLOT lt x gt HISTOgram NUMBins NOTE Undefined for non
43. a statistical measure The measurement requires a sufficient record length so that all deterministic effects can be observed and the random jitter can be modeled Width BER Ul mean TJ BER Mask Hits The number of unit intervals for which mask violations occurred A mask violation occurs when during a unit interval the waveform passes through a segment of the defined mask Mask hits are separately tallied for Segment 1 upper Segment 2 center of eye mask and Segment 3 lower and the total for all three segments is also reported Thus as many as three hits can be added to the total count for each unit interval The population for this measurement gives the total number of unit intervals observed Table of Measurements Amplitude Definitions of the amplitude related measurements are given in the following table Table 11 Amplitude measurements definitions Measurement Description High Vertical value in the central portion of the unit interval UI for high data bits The percent of the UI over which the waveform is evaluated is adjustable as is the method by which a single value is derived from this span The measurement may optionally be limited to transition or non transition bits only DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 11 Amplitude measurements definitions cont Table of Measurements Standard Measurement Description Low Vertical value in the centr
44. be dismissed manually Cancel Discards all changes and closes the Preferences window OK Accepts all changes and closes Preferences window Related Topics B Preferences Measurement W Preferences Path Defaults DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Preferences Measurement Preferences Measurement Click Analyze gt Jitter and Eye Analysis gt Preferences gt Measurement to view the following eo Preferences Setup 22o Setup T Limit RiseFall measurements to transition bits only General M Enable high performance eye rendering Dual Dirac Model PCUFB DIMM Y Waveform Interpolation Type Linear Y Path Defaults The Measurement tab allows you to limit Rise and Fall measurements to transition bits only or allow these measurements for all bits Here the transition bits refer to edge transitions for which the preceding transition was only one unit interval away This may be important for signals with pre emphasis since the transition following a string of two or more like bits has an intentionally low swing that you may not want to measure You can enable or disable high performance eye rendering from this tab This provides a trade off between greater fidelity or greater rendering speed You can also select the Dual Dirac model and the waveform interpolation type Table 23 Preferences Measurement options Item Description Limit Rise Fall measurements to transition
45. button Option Parameters Default setting Vertical Scale Log Linear Linear Number of Bins Resolution 25 50 100 250 500 250 Horizontal Scale Auto Scale Set Clear Set Center 1 00E 12 to 1 00E 12 1 00E 07 Span 1 00E 12 to 1 00 E 12 4 00E 09 Eye Diagram Plot Parameters The Eye Diagram plot has the following parameters Option Parameters Default setting Mask On Off Off Browser C NTekApplicationsNDPO JET Masks Horizontal Scale Auto Scale Set Clear Set Resolution 2 00E 13 to 2 00E 08 1 00E 12 Superimpose Reference Clock Eye Set Clear Clear if available Ref Clock Alignment Auto Centre and Left Auto Spectrum Plot Parameters The Spectrum plot has the following parameters Option Parameters Default setting Vertical Scale Log Linear Linear Base 20 to 15 15 Horizontal Scale Log Linear Linear Mode Normal Average Peak Hold Normal DPOJET Jitter and Eye Diagram Analysis Tools Parameters Time Trend Plot Parameters The Time Trend plot has the following parameters Time Trend Plot Parameters Option Parameters Default setting Mode Vector Bar Vector Phase Noise Plot Parameters The Phase Noise plot has the following parameters Option Parameters Default setting Vertical Position Baseline 200 to 0 170 Bathtub Plot Parameters The Bathtub plot has the following parameters Option Parameters Default setting Vertical Scale Log
46. changes and closes the window Measurement and Qualify sources must have the same Horizontal Sample Rate Record Length and Position to ensure that measurements function properly t For measurements that require clock recovery only the first qualified region will be measured even if multiple qualified regions are present t The default behavior for all reference levels is to automatically adjust based on the signal amplitude after a Clear operation unless you disable the autoset checkbox in the source configuration panel Whether you use the Qualify with Logic dialog box to adjust the levels or not be aware that the levels may change if automatic adjustment is still enabled For more information refer to Automatic Versus Manual Reference Voltage Levels see page 72 Search Behavior in DPOJET When search is configured the application analyzes the identified marks on the source waveform Read and Write bursts are selected in ASM when search is selected as the qualify source Each Mark indicates the start and stop of a burst These marks are used by the DPOJET measurement when the qualify source is configured to Search You can configure up to eight searches Searchl Search8 in ASM Advanced Search and Mark The same search number gets reflected in DPOJET Search is used for Multiple burst analysis Multiple burst is used for all DDR measurements except clock measurements For more details refer to your oscilloscope online help Po
47. clock or data If the signal is a clock the Clock Edge control will determine which edges are used otherwise the Clock Edge control will have no effect Clock Edge Rise Only the rising edges of the signal are used Fall Only the falling edges of the signal are used Both Both the rising and falling edges of the signal are used DPOJET Jitter and Eye Diagram Analysis Tools 111 Operating Basics Configuring Edges for Skew Measurements Configuring Edges for Skew Measurements This configuration tab is displayed for Skew measurements Item Description From Edge Defines which edge of the first waveform is used to take measurements Rise Only the rising edges of the signal are used Fall Only the falling edges of the signal are used Both Both the rising and falling edges of the signal are used To Edge Defines which edge on the second waveform is used to take measurements Same as From Each measurement is defined by a pair of like edges Rise to Rise or Fall to Fall Opposite as From Each measurement is defined by a pair of opposing edges Rise to Fall or Fall to Rise Configuring Edges for Differential CrossOver Voltage Measurements This configuration tab is displayed for Differential CrossOver Voltage measurements 112 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Configuring Edges for Phase Noise Measurements Item Description Main Edg
48. consecutive bits of the same polarity result in N identical period measurements Frequency The inverse of the period for each cycle or unit interval CC Period N Period The cycle to cycle period the difference in period measurements from one cycle to the next that is the first difference of the Period measurement The duration of N periods Pos Width Amount of time the waveform remains above the mid reference voltage level Neg Width Duty Cycle Amount of time the waveform remains below the mid reference voltage level The ratio of positive width to period expressed in 9o Duty Cycle The ratio of negative width to period expressed in 96 CC Duty The difference between two consecutive positive widths CC Duty The difference between two consecutive negative widths DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table of Measurements Jitter Table of Measurements Jitter Definitions of the jitter related measurements are given in the following table NOTE All jitter measurements except TIE are statistical measurements that require sufficient record length so that all deterministic effects can be observed and the random jitter can be modeled Table 8 Jitter measurements definitions Measurement Description TIE Time Interval Error is the difference in time between an edge in the source waveform and the corresponding edge in a referen
49. eR 28 87 Brick Wall Filter Configuration csse seme eme eme messe eese 89 Advanced Filter Configuration 00 0 cece cence ener eee eme ee se een 90 Clock Recovery About Clock RecoVery E SERRE ERR SR IUE ERU ETREPYRS 93 About Constant Clock Recovery 10 0 0 cccc cece cence een eee nen esee eene 93 Constant Clock Mean i oec p ne ET e S ERE e deg Be Eus 94 Constant Clock Median eec oorr retro To EHE POUR ERART VP rea 95 Constant Clock Fixed i assess e eee tiere Re adire pe r pera tas Dp ERES 96 Clock Recovery Advanced Setup sssssssssssssssssssssssseee eene 97 About PLL Clock Recovery Setup sss meme 98 PEL Standard BW 5 5 ticos es tees one Feet Tr Dee AE qne HERR Eee bERER eee ARES Er a 98 PLL Custom BW 51 1 uie REED RR ER Me ERE aoe 99 About Explicit Clock Recovery nrrssirirs sarircrrcieorii iet e me memes 100 Explicit Clock Edge esses e He mee eee 101 Advanced Explicit Clock Edge sss mene 102 Explicit Clock PELE ood sesto ride RUE e ER ER ERE EDO EU rra ge Revs 102 Advanced Explicit Clock PLL ccc ccc e cece cee nnn nent nent mene 103 Effect of Nominal Clock Offset on Eye Diagrams ccccce nce eee cence ene enaneees 104 Bit Config for Eye Height Measurements 0 ccce ccc e cece eee e ee ee emen 104 Bit Config for Mask Hits Measurements 00cccccen cee ee eee ee eese ne eee 105 Bit Config for Amplitude Measurement
50. histogram plots DPOJET PLOT lt x gt HISTOgram NUMBins Sets or queries the current histogram resolution Syntax DPOJET PLOT x HISTOgram NUMBins Inputs TWENtyfive FIFTY HUNdred TwOFifty FIVEHundred Outputs TwENtyfive FIFTY HUNdred TwoFifty FIVEHundred NOTE Undefined for non histogram plots DPOJET PLOT lt x gt HISTOgram HORizontal CENter Sets or returns the histogram center Syntax DPOJET PLOT lt x gt HISTOgram HORi zontal CENter Inputs lt NR3 gt Outputs lt NR3 gt NOTE Undefined for non histogram plots DPOJET Jitter and Eye Diagram Analysis Tools 261 GPIB Commands DPOJET PLOT lt x gt HISTOgram HORizontal SPAN DPOJET PLOT lt x gt HISTOgram HORizontal SPAN Sets or returns the histogram span Syntax DPOJET PLOT x HISTOgram HORi zontal SPAN Inputs NR3 Outputs NR3 NOTE Undefined for non histogram plots DPOJET PLOT lt x gt SPECtrum VERTical SCALE Sets or returns the vertical scale setting for applicable plots either Linear or Log Syntax DPOJET PLOT lt x gt SPECtrum VERTical SCALE Inputs LINEAR LOG Outputs LINEAR LOG NOTE Undefined for non spectrum plots 262 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET PLOT x SPECtrum HORizontal SCALE DPOJET PLOT x SPECtrum HORizontal SCALE Sets or returns the horizontal scale setting for applicable plo
51. is displayed for DDR tERR n measurement Jitter and Eye Diagram Analysis Tools L xim Data Eye Width Edges Number of Periods napos tAC Diff tDOSCK Diff ck pa E pos ck tDQSO Diff i pas na oore oa a General Global Item Description Clock Edge Rise Measurements are initiated only on the Rising edges of the Clock signal Fall Measurements are initiated only on the Falling edges of the Clock signal Number of Periods Timing error tERR requires number of periods n per to calculate error across multiple consecutive cycles from tCK avg You can configure n per up to 50 with a resolution of 1 Window Size Measurement analysis is done on a window of size 200 cycles with a step increment of 1 cycle As per the standard the default window size is 200 You can set window size up to 1M Configuring Edges for DDRtJIT per DDRtCK avg and DDRtJIT duty This configuration tab is displayed for DDRtJIt per DDRtCK avg and DDRtJIT duty Jitter and Eye Diagram Analysis Tools DDR tJIT per 1 DDR tCH avg 1 Eren ren forumam Ren 118 Filters General DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Sequencing Item Description Clock Edge Rise Measurements are only initiated on the Rising edges of the clock signal Fall Measurements are only initiated on the Falling edges of the clock signal Wind
52. measurement DPOJET Jitter and Eye Diagram Analysis Tools 123 Operating Basics Results as Plots Before exporting results to a reference memory the application checks for the following If any of the ref waveforms are already used as source for one of the measurement s then you cannot export the results on those ref destinations The application prevents exporting by displaying an error message 2003 see page 170 If all the reference waveforms Refl Ref4 are already used as sources for various measurements the Export Results to Ref Waveform is not displayed Instead an error message 2002 see page 170 is displayed If a ref destination is assigned to a measurement from the list which is not empty that is 1f the ref is already defined and holds any other recalled waveform a warning prompts you from overwriting the existing definition of the selected destination ref In case of any error 2002 or 2004 or warning Overwriting the existing definition and you select the response as No the destination ref reverts to its previous value For example if the selected measurement is Period Refl and the destination ref assigned to the measurement is Ref3 and if you try to change the destination from Ref3 to Refl an error message 2003 see page 170 is displayed Ref3 is retained as the destination ref Time trend result export to the reference waveform for a measurement is independent of time trend plot Time tren
53. measurement calculates the change in voltage level across a transition in the waveform The application calculates the High Low using the following equation Visas 1ow 02 Viva G V aye 1 Where Vuiau Low is the high low amplitude measurement result n is the index of a selected transition DPOJET Jitter and Eye Diagram Analysis Tools Algorithms V Diff Xovr i is the index of the UI bit location preceding the transition i is the index of the UI bit location following the transition Viever OP Vpercenr i is the state level of the unit interval bit period OP is the selected Operation either Mean or Mode Vpercenr 18 the set of voltage samples over the selected portion percent of the unit interval ranging from 1 to 100 NOTE If there are no waveform samples that fall within the identified percentage of the unit interval the single nearest waveform sample preceding the center point of the unit interval will be used V Diff Xovr The Differential Crossover Voltage measurement V Diff Xovr calculates the voltage level at the crossover voltage of a differential signal pair If there is timing jitter on one of the pair of signal lines relative to the other the crossover point will be modulated by the jitter The measurement is calculated using the following equation Crossover Tr ourcel Crossover V m n T n Where VCrossover is the crossing voltage V Source is the voltage
54. measurements you should do so before you take any measurements NOTE When you run any measurement Sampling mode in the oscilloscope should be set to Real Time You need to do this setting in the oscilloscope to take DPOJET measurements Selecting a Measurement To take a measurement click Analyze gt Jitter And Eye Analysis gt Select Alternatively to take a PCI Express measurement click Analyze gt PCI Express Jitter and Eye Diagram Analysis Tools Measurements Period Freq Period Pos Width Neg Width Freq N Period DutyCycle Duty Cycle CC Period CC Duty CC Duty Ampl Standard The application provides you different methods to set up the application B Wizard B Measurement Setup sequence The measurement categories are Period Freq Jitter Time Eye Amplitude and Standard as shown in the following table 58 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 26 Measurement selections Selecting a Measurement Category Measurements Period Freq Period Pos Width Neg Width Freq N Period Duty Cycle Duty Cycle CC Period CC Duty CC Duty Jitter TIE RJ RJ 66 Jitter Summary TJ BER DJ DJ 86 Phase Noise PJ DDJ DCD Time Rise Time Fall Time Skew High Time Low Time Setup Hold Eye Width Width BER Height Mask Hits Ampl High Common Mode Low T nT Ratio High Low V Diff Xovr Standard D
55. none of the supplied mask files meets your need you may create a custom mask file with a text editor by using one of the existing mask specification files as a template Bit Config for Amplitude Measurements 106 This configuration tab is present only for High Low and High Low measurements You can select the waveform bit type All Bits Transition Non Transition and method Jitter and Eye Diagram Analysis Tools Table 56 Bit Config for amplitude measurements Item Description Bit Type All Bits Eye analysis includes both transition and non transition bits Transition Eye analysis only on transition bits Non Transition Eye analysis only on non transition bits Measure the Center X of the Bit Determines what percentage 1 to 100 of a unit interval centered in the middle of the bit shall be included in each measurement The waveform points selected by the percentage form a distribution vertical histogram from which a single value is extracted based on the Method control Method Determines whether the Mean value or the Median of the selected distribution is used for the measurement value for each unit interval DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Bit Config for PCI Express Measurements Bit Config for PCI Express Measurements This configuration tab allows you to select which waveform bit types Transition Non Transition or All Bits are included when t
56. of the first source waveform Crossover js the crossover time when the Sourcel and Source2 waveforms are equal in voltage DDR Setup and Hold Measurements The following four measurements are modified versions of the basic Setup and Hold measurements found on the Time tab In contrast to the basic measurements which always use the Mid voltage reference to determine edge times these measurements use the High and Low references as required to conform to some DDR specifications For all these measurements the Strobe signal DQS is assigned to Sourcel and the Data signal is assigned to Source2 The measurements with names ending in Diff are appropriate if you have a have a differential Data Strobe DQS signal Either connect to DQS and DQS with a differential probe or acquire these signals with two single ended probes and create a pseudo differential signal using a Math expression for example Math Chl Ch2 In this case the data DQ signal uses thresholds other than the mid threshold but the DQS signal uses a mid threshold set to 0 V DPOJET Jitter and Eye Diagram Analysis Tools 191 Algorithms DDR Setup and Hold Measurements Check that the DPOJET reference levels for the data source are set to match the proper values of VIH ac VIH dc VIL ac and VIL dc for the DDR technology that you are measuring Depending on which edges you choose to measure Rising Falling or Both you may not need to set up all of t
57. reference level The closest data edge to the clock edge that falls within the range limits 1s used The application calculates this measurement using the following equation pony TM E pand Where T Setup is the setup time T Main is the Main input clock VRefMidMain crossing time in the specified direction T 2nd is the 2nd input data VRefMid2nd crossing time in the specified direction Hold The Hold Time measurement is the elapsed time between when the clock waveform crosses its own voltage reference level and the designated edge of a data waveform The closest data edge to the clock edge that falls within the range limits is used The application calculates this measurement using the following equation A aid qe pw Where T Hold js the hold time T Mainis the Main input clock VRefMidMain crossing time in the specified direction T 2nd is the 2nd input data VRefMid2nd crossing time in the specified direction DPOJET Jitter and Eye Diagram Analysis Tools 185 Algorithms Eye Width Eye Width The Eye Width measurement is the measured minimum horizontal eye opening at the zero reference level The application calculates this measurement using the following equation Toys waprg 7 Ul ave TIE mor Where Ul yc is the average UI TIE is the Peak Peak TIE Width BER Width BER is the Eye Width at a specified Bit Error Rate BER This extrapolated value predicts a horizontal eye opening that will be violate
58. saving statistics Clear All Deselects all the measurements from the list Save Statistics Save Saves the current statistics of selected target measurements to a log file File Name Browse Saves the csv file in the specified directory The file format is YYMMDD HHMMSS Stats csv The default directory is c TekApplications DPOJET Logs Close Accepts the changes and closes the window DPOJET Jitter and Eye Diagram Analysis Tools 37 Operating Basics Export Data Snapshot Measurement NOTE The default location for saving log files can be changed in the Preferences dialog box Related Topics B Export Data Snapshot Measurement Export Data Snapshot Measurement You can save a snapshot of the data points in csv format The default location is C TekApplications DPOJET Logs Measurements Click Analyze gt Jitter and Eye Analysis gt Export gt Data Snapshot gt Measurement to view the following Statistics Measurement Folder C TekApplications DPOJET Logs Measurements Grows 38 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 15 Data Snapshot Measurement options Item Select Target Measurements Export Data Snapshot Measurement Description Displays the measurement list Click a row to select the measurement By default all measurements are selected Select All Selects all the measurements in the li
59. single ended strobe DQS waveform and the designated edge of a data waveform The closest data edge to the clock edge that falls within the range limits is used The strobe is placed on Sourcel and the Data is placed on Source2 This is the base Hold measurement which does not include slew rate derating Slew rate derating tables can be found in the applicable JEDEC specification This measurement is identical to the basic Hold measurement except that instead of using the Mid reference voltage for determining edge times it uses the High and Low reference voltages for the data The mid reference level is still used for the strobe DQS For more details on the reference voltage setup refer to DDR Setup Hold Reference Levels Differential DQS see page 192 The application calculates this measurement using the following equation To TAM 77 Where T Hold is the hold time T Main is the Main input strobe or DQS crossing time of VRefMid in the specified direction T 2nd is the 2nd input data or DQ crossing time of VRefHighFall for falling data edges or VRefLowRise for rising data edges DDR tCL avg DDR tCL avg is defined as the average low pulse width calculated across 200 cycle window of consecutive low pulses The application calculates this measurement using the following equation 198 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms DDR tCK avg N tCL avg CL UI PaCK avg ja Where N 200 w
60. the TIE associated with that pattern is considered accurate Using a larger population means that more observations are averaged together so that the variance of the measurement is reduced Specifying a larger population has the disadvantage of requiring a longer measurement period before results can be calculated and it may be necessary to sequence the instrument several times before enough statistics are accumulated to provide results The arbitrary pattern approach for measuring jitter may not be appropriate if there are very long duration memory effects in your data link An example would be if there are impedance mismatch reflections that arrive long enough after the initial edge to fall outside the analysis window Jitter and Eye Diagram Analysis Tools Data Signal Settings Arbitrary X Table 59 RJ DJ analysis of arbitrary options Item Description Data Signal Settings Pattern Type Selects between repeating or arbitrary pattern analysis Window Length When the Pattern Type is set to Arbitrary sets the pattern window length in terms of Unit Interval UI used for arbitrary pattern RJ DJ separation DPOJET Jitter and Eye Diagram Analysis Tools 109 Operating Basics Configuring Edges Table 59 RJ DJ analysis of arbitrary options cont Item Description Population When the Pattern Type is set to Arbitrary sets the minimum population limit for each pattern to be qualified for arbitrary pattern RJ DJ separati
61. the reference levels manually follow these steps 1 Click T icon in the table which lists the selected measurements to view the source configuration screen 2 Select the desired source from the Source list NOTE You cannot select inactive sources DPOJET Jitter and Eye Diagram Analysis Tools T3 Operating Basics Ref Levels 3 Clear the Autoset option for the sources you wish to set manually 4 Select the reference levels or hysteresis options and manually adjust the values The values will not change when you select Autoset or take measurements NOTE A source will become inactive if all measurements on that source are removed If a new measurement is then added on that source the source once again becomes active and defaults to Autoset If you clear all measurement on a source that was set to Manual you must reselect the Manual state if desired when the source is again added Table 31 Configure sources ref levels configuration Item Description Autoset Calculates and displays the reference voltage levels for all sources where the autoset option is set according to the Autoset Ref Level Setup Setup Specifies the Base Top method and relative percent to be used for all reference voltage levels when autoset occurs Ref Levels Setup one level per source t Rise High Sets the high threshold level for the rising edge of the source Rise Mid Sets the middle threshold level for the ris
62. you save E3008 There are currently no results to save Please run a measurement E3010 Access to file directory denied Please ensure that the file directory has read write permissions E3011 Mask Hits Measurements will not be selected as this feature is not available for Mask Hits measurement E3012 Folder does not exist E4000 Not enough data points Unable to render plot s E4001 Out of memory Please remove a measurement and try again E4002 Not enough data points for spectrum computation E4003 Low Memory The entire waveform was not processed and the measurement results are for part of the waveform E4004 Edge Extraction failure E4005 Qualifier Horizontal parameters do not match across waveforms W4006 A maximum of 10 qualifier zones are supported The entire waveform will not be processed and hence partial measurement results are available Measurement Values 172 The following table lists the maximum and minimum values of all measurements NOTE Measurement Range Limits are provided for each measurement under the General configure tab of the DPOJET application These range limits are always ON OFF is disabled for two source measurements such as Skew Setup Hold and others The range limits are used by the algorithms to associate the valid edge of first source to the valid edge of the second source Measurement Range Limits Max Measurement Range Limits Min Name Default Max Min Default Max
63. 0ps Os Custom Measurement Name 1DS Diff base Description Disables the application from using the specified measurement limits 86 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 44 General options cont Item On Filters Description Enables the application to use the specified measurement limits Max or Min value Specify the maximum and minimum range of valid measurement values measurements The default values for the Measurement Range Limits options vary by measurement Custom Measurement Name Option to modify the measurement name Allows adding a user specified name to any measurement This is useful for aligning DPOJET measurements with a user measurement list or standard NOTE Ifa max value smaller than the min value is entered it is accepted and the min value is also silently reduced to the same value Likewise if a min value larger than the max is entered both are set to that value Filters This configuration tab allows you to modify the measurement data by applying a High Pass filter to block out low frequency band components or a Low Pass filter to block out high frequency band components For Example Selecting a 1 MHz high pass filter can reduce the effect of SSC on results For some measurements Period Frequency TIE Duty Cycle Duty Cycle CC Duty CC Duty CC Period Positive Width Negative Width N Period Rise Time Fall T
64. 1 Operating Basics One Touch Jitter One Touch Jitter 22 One Touch Jitter is a process for automatically performing complex jitter analysis with a single menu selection The process selects a waveform source sets the horizontal and vertical scales chooses measurements generates statistical results and creates plot summary Histogram Spectrum Bathtub and Eye Diagram To run this process select Analyze gt Jitter and Eye Analysis gt Wizard gt One Touch Jitter By default the DPOJET application chooses an appropriate source for the jitter measurements from the available active source s amplitude gt 50 mV before generating the jitter summary Jitter and Eye Diagram Analysis Tools Measurements Period Freq Period Pos Width Neg Width N Period Duty Cycle Duty Cycle CC Period CC Duty CC Duty Standard NOTE If the source amplitude is not greater than 50 mV the application displays a message Signal amplitude is extremely low for the selected source The following logic is used if none or many sources are active B None of the sources are active see page 22 Only one source is active see page 23 m Two sources are active see page 23 m Three sources are active see page 23 m Four or more sources are active see page 23 Case 1 None of the sources are active If none of the sources are active you are prompted to select any one of the Ch Ref or Math sources
65. 1667 Go to Plots Select Time Trend for Period measurement Click Single to run the application When complete the result statistics is shown in the results tab The Time Trend plot is as shown Case 2 A pair of TIE for showing jitter integration caused by SSC and the effect of a high pass filter on SSC spectrum plots 1 2 Click Jitter to select TIE measurement Select Math1 see page 148 as the source for both TIE and TIE2 Jitter and Eye Diagram Analysis Tools Measurements Jitter RJ 66 Summary DJ 60 Phase Noise DPOJET Jitter and Eye Diagram Analysis Tools 153 Tutorial Stopping the Tutorial 3 Click Configure Do the following settings for TIE and TIE2 in the Filters configuration tab Select No Filter for TIEI Select 21d order High Pass filter for TIE2 In this example the F1 cut off frequency is set to 1 GHz Go to Plots Select Time Trend for both TIE and TIE2 Select Spectrum plot for both TIE1 and TIE2 Click Single to run the application When complete the result statistics is shown in the results tab Jvc cUm cde A Plot Summary window shows Time Trend plots for TIE1 TIE2 and Spectrum plots for TIE1 TIE2 B RAAN oa lm ea lssBRm SG Reset 2o ME Time trend NOTE You can log results as statistics see page 37 measurement data points see page 38 to a csv file and worst case waveforms see page 46 to a wfm file Stopping the Tutorial If you need mo
66. 20 V to 20 V 1V Fall High 20 V to 20 V 1V Fall Mid 20 V to 20 V OV Fall Low 20 V to 20 V 1V Hysteresis 0 to 10 V 30 mV Autoset Ref Levels Parameters Option Parameters Default setting Base Top Method m Min Max Auto Low High Histogram Full Waveform B Low High Histogram Center of Eye Auto Rise High 1 to 99 90 Rise Mid 1 to 99 50 Rise Low 1 to 99 10 Fall High 1 to 99 90 Fall Mid 1 to 99 50 Fall Low 1 to 99 10 Hysteresis 0 to 50 3 DPOJET Jitter and Eye Diagram Analysis Tools Parameters Preferences Parameters Preferences Parameters The Analyze gt Jitter and Eye Analysis gt Preferences includes the following tabs General B Measurement Path Defaults Option Parameters Default setting General Display Units Seconds Unit Intervals Seconds Default Image Type PNG JPG BMP PNG Notifier Duration 2 to 20s 5s Measurement Limit Rise Fall measurements to Set Clear transition bits only Enable high performance eye Set Clear Set rendering Dual Dirac Model Fibre Channel PCI FB DIMM PCI FB DIMM Waveform Interpolation Type Linear Sin x x Linear Path Defaults Default image export directory Browser c TekApplications DPOJET Images Default logging export directory Browser C NTekApplicationsNDPOJETNLogs Default report output directory Browser C NTekApplicationsNDPOJETNReports Deskew Parameters The Analyze gt Jitter and Eye Analysis gt Deskew includes the follo
67. 21 Pos Width 16 Positive and Negative CC Duty 179 Positive and Negative Duty Cycle 178 DPOJET Jitter and Eye Diagram Analysis Tools Index Positive and Negative Width 176 Preferences Parameters 157 Preferences Setup 51 Preferences General 51 Preferences Measurement 53 Print Figure 140 Printing Plots 143 Probes 7 Product Description 5 Progress Bar Status Messages 169 Progress indicator 119 Q Qualify Horizontal Sample Rate 82 R ramp function 90 Ramp Time 93 ramped up 90 Recalc 62 recall 15 Recalling a Default Setup 15 Recalling a Saved Setup 15 Ref Level Menu Parameters 156 Ref Levels 70 Ref Levels Setup 74 reference levels 70 Related Documentation 2 report export directory 55 Report files 13 Reports 61 Reports Format 145 Requirements and Restrictions 7 Results 61 Results as Plots 124 Returning to the Application 14 Rise Time 183 Rising Versus Falling Thresholds 71 RJ 17 RJ DJ 107 RJ DJ Analysis of Arbitrary Pattern 108 RJ DJ Analysis of Repeating Pattern 108 RJ DJ Separation for Arbitrary Patterns 206 289 Index RJ DJ Separation via Spectrum Analysis 205 RJDJ Analysis Parameters 163 Run 62 run a measurement 25 S Safety Summary xi Same as From 112 Save Current Stats 121 Save Options 144 Saving a Setup 15 Select 61 Select Measurement 26 Select Plots 31 Select Sources 29 Selecting a Measureme
68. 6 EdgeExtractor Edge Extractor EyeHeight Eye Height EyeMaskHits Eye Mask Hits EyeWidth Eye Width EyeWidthBER Eye Width BER FallTime Fall Time Frequency Freq HighTime High Time Hold Hold LowTime Low Time NegativeDutyCycle Duty Cycle NegativeDutyCycleCycle CC Duty NegativeWidth Neg Width NPeriod N Period PerCycleCycle CC Period Period Period PhaseNoise Phase Noise PJ PJ PositiveDutyCycle Duty Cycle PositiveDutyCycleCycle CC Duty PositiveWidth Pos Width RiseTime Rise Time RJ RJ RJ RJ 86 Setup Setup Skew Skew TIE TIE TJ TJ BER TNTRatio T nT Ratio Error Codes Code Description W410 Number of edges are not sufficient for a measurement Positive Width E1001 Vertical Autoset Failed Signal on Source x has extreme offset E1002 Vertical Autoset Failed Amplitude of Source x is too small E1003 Vertical Autoset Failed Amplitude or DC offset of Source x is too high 170 DPOJET Jitter and Eye Diagram Analysis Tools Reference Code Error Codes Description E1004 E1005 Vertical Autoset Failed No signal on Source x Vertical Autoset Failed Signal on Source x exceeds top of scale E1006 Vertical Autoset Failed Signal on Source x exceeds bottom of scale E1007 Vertical Autoset Failed Signal on Source x is clipped on top E1008 E1009 Vertical Autoset Failed Signal on Source x is clipped on bottom Vertical Autoset Failed Measurement error ISDB error code 7 6 on Source x E1010
69. 91 Blanking Time 93 Brick Wall Filter 89 Browse 11 C CC Duty 16 CC Period 178 Check Boxes 11 Clear 62 Clear Log 52 Clock Edge 115 Clock Multiplier 101 Clock Recovery 93 Clock Recovery Advanced Setup 97 clock recovery methods 93 Clock Recovery Parameters 161 Clock Source 101 CM V 20 comma separated value 41 Command button 11 Common Mode 189 compatibility 6 Compatibility 6 configure 25 Configure 61 Configure Autosets 30 Configure Measurement Jitter Summary 28 Configure Measurement Skew 27 Configuring Bathtub Plot 131 Configuring Edges 110 Configuring Edges for CC Period Duty Cycle 115 Configuring Edges for DCD 116 Configuring Edges for Differential CrossOver 112 Configuring Edges for N Period 114 Configuring Edges for Phase Noise 113 Configuring Edges for Skew 112 Configuring Edges for Two Source Measurements 115 Configuring Histogram Plot 133 Configuring Measurement 27 DPOJET Jitter and Eye Diagram Analysis Tools Index Configuring Phase Noise Plot 136 Configuring Plots 130 Configuring Population Limit 85 Configuring Qualify with Logic 83 Configuring Spectrum Plot 132 Configuring Time Trend 132 Configuring Transfer Plot 134 Connecting to a Device Under Test DUT 34 Constant Clock Fixed 96 Constant Clock Mean 94 Constant Clock Median 95 Content Options 143 Control Panel 61 Control Panel Parameters 158 Conventions 2
70. Clock Forces the signal to be interpreted as a Clock Measurements will take place on the edges specified by the Clock Edge control Data Forces the signal to be interpreted as a Data Both rising and falling edges are used Auto Allows the application to automatically detect whether the signal is clock or data If the signal is a clock the Clock Edge control will determine which edges are used otherwise the Clock Edge control will have no effect Clock Edge Rise Only the rising edges of the signal are used Fall Only the falling edges of the signal are used Both Both the rising and falling edges of the signal are used N Specifies number of cycles or unit interval in each N period group Edge Increment Specifies the temporal displacement in edges between consecutive measurements DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Configuring Edges for Two Source Measurements Configuring Edges for Two Source Measurements This configuration tab is displayed for two source measurements Setup and Hold Jitter and Eye Diagram Analysis Tools Ch1 Ch2 Edges Filters Global Item Description Clock Edge Rise Only the rising edges of the signal are used Fall Only the falling edges of the signal are used Both Both the rising and falling edges of the signal are used Data Edge Rise Only the rising edges of the signal are used Fall Only the falling edges of the sig
71. Cursors and Reset Cursors 140 Cursors in a Plot 141 Custom Measurement Name 87 Custom Source Name 64 Customer Feedback 3 D Damping 99 Data Array 126 Data Edge 115 Data Logging Parameters 158 Data Logging Measurement 43 Data Logging Statistics 41 Data Logging Worst Case 46 DCD 17 DDJ 182 DDR Hold Diff 20 DDR Hold SE 20 DDR Setup Diff 20 DDR Setup SE 20 DDR tCH avg 21 DDR tCK avg 20 DDR tCL avg 20 DDR tERR m n 21 DDR tERR n 21 DDR tJIT duty 21 DDR tJIT per 21 287 Index DDRtJlt per 118 Description 121 Deskew 34 Deskew Parameters 157 Deskew Summary 36 Details 120 DJ 17 DPOJET 2 Dual Dirac Deterministic Jitter 181 Dual Dirac Model 54 Dual Dirac Random Jitter 180 DUT 2 Duty Cy Cy 16 Duty Cycle 16 E E1001 170 E1002 170 E1003 170 E1004 171 E1005 171 E1006 171 E1007 171 E1008 171 E1009 171 E1010 171 E1012 171 E1013 171 E1020 171 E1021 171 E1022 171 E1035 171 E1040 171 E1054 171 E1055 171 E1056 171 E1057 171 E1058 171 E1059 171 E2002 171 E2003 171 E2004 171 E2005 171 E2006 171 E2007 171 E2008 171 E3001 171 E3002 171 288 E3003 171 E3004 172 E3005 172 E3006 172 E3007 172 E3008 172 E3010 172 E3011 172 E3012 172 E4000 172 E4001 172 E4002 172 E4003 172 E4004 172 E4005 172 Edge Increment 114 Error Codes 170 Error log file 13 Explicit Clock Recove
72. DPOJET Jitter and Eye Diagram Analysis Tools Online Help FOOT AUC TEE Tektronix 077 0048 03 S DPOJET Jitter and Eye Diagram Analysis Tools Online Help www tektronix com Tektronix 077 0048 03 S Copyright O Tektronix All rights reserved Licensed software products are owned by Tektronix or its subsidiaries or suppliers and are protected by national copyright laws and international treaty provisions Tektronix products are covered by U S and foreign patents issued and pending Information in this publication supersedes that in all previously published material Specifications and price change privileges reserved TEKTRONIX and TEK are registered trademarks of Tektronix Inc DPOJET Jitter and Eye Diagram Analysis Tools Online Help Part Number 076 0114 03 Contacting Tektronix Tektronix Inc 14200 SW Karl Braun Drive P O Box 500 Beaverton OR 97077 USA For product information sales service and technical support n North America call 1 800 833 9200 Worldwide visit www tektronix com to find contacts in your area Table of Contents Table of Contents General Safety Summary oec bt ex e EE TA ERA DE RARE EE e uu Rees dese SEE ET ET ed xi Introduction to the Application igi 1 Five Time Free Trial zi iet tese bobsled ede D ebbe onu e o rd cune Ut N rEta ren aUas 1 Related Documentations 4 5 2a tetro x rm E ERES eo onan cela oou FATE gu Es shes Dad SERRE Y teks s 2 n nginioirc T
73. DR DDR Setup SE DDR Hold Diff DDR tCK avg DDR tJIT duty DDR Setup Diff DDR tCL avg DDR tERR n DDR tJIT per DDR Hold SE DDR t CH avg DDR tERR m n PCI Express 2 0 PCle T Tx Diff PP PCle T TXA PCle T Tx Fall PCle Tmin Pulse PCle T nT Ratio PCle T Tx Rise PCle UI PCle Med Mx Jitter PCle T RF Mismch Two Source Measurements Wizard The Serial Data Jitter Guide allows you to set up configure and run the selected set of measurements without requiring any knowledge of the control menus However it does not provide access to many of the advanced features Measurement Setup Sequence The Measurement Setup Sequence buttons in the left navigation panel shows the logical order you would follow to set up the application if you do not use the Wizard DPOJET Jitter and Eye Diagram Analysis Tools 99 Operating Basics Warning Log Notifiers Warning Log Notifiers Warning Log Notifiers display error messages or warnings Warnings A or Error 3 messages are also shown in the results tab You can click View Log to view the error log information in a text editor Click OK to discard the displayed error message 1054 Ref Level Autoset x 63 Error in setting reference levels for Ch1 You can set the duration for which the warning notification should appear on the screen in the Preferences see page 51 dialog box or click OK to discard the warning information 1053 Ref Level Autoset x
74. Data Logging Measurement Configuration Summary Export to Ref and Data Snapshot The custom source names DQ and DQS appear in the following screens B Measurement table 64 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Jitter and Eye Diagram Analysis Tools Measurements Period Freq Pos Width Neg Width Period Joo N Period sDutyCycle Duty Cycle CC Period CC Duty CC Duty Standard Source Configuration Source Configu Freq DDR Setup Diff1 v S Results Jitter and Eye Diagram Analysis Tools Custom Source Name E2 tDH Diff base DOS 778 50ps tDOSH DOS 96 072ps 3 0997ns 5 3622ps 50 293ps 1 5644ns 72 524ps 68 559ps W Plots DPOJET Jitter and Eye Diagram Analysis Tools 204 17ps 7 4255ns 259 29ps 276 37ps 22 500ps 26 667ps 6 0000ps 555 54fs ne 7 5833ps 181 67ps 7 3988ns 253 29ps 275 82ps 0 0000s 176 17ps 4 8987ns 239 28ps 22 222ps Min cc 0 0000s 164 00ps 4 8717ns 161 67ps 24 222ps 65 Jitter and Eye Diagram Analysis Tools Plots Data Eye Width napos tDH Diff base L jpospo tDOSH jes tDOSL pos Spectrum Transfer Phase Noise tDS Diff base posa Time Trend Data Array Histogram Eye Diagram Waveform Bathtub Data Snapshot Select Target Measurements Statistics me EyeWidth DO DOS tDH Diff base DOS DQ Z tDOSH bas i
75. Diff T Main 1s the Main input strobe or DQS crossing time of VRefHighFall for falling strobe edges or VRefLowRise for rising strobe edges T 2rd is the 2nd input data or DQ crossing time of VRefLowFall for falling data edges or VRefHighRise for rising data edges DDR Setup Diff The DDR Setup Diff measures the elapsed time between the designated edge of a data waveform and when the differential strobe DQS waveform crosses its own voltage reference level The closest data edge to the clock edge that falls within the range limits is used The strobe is placed on Sourcel and the Data is placed on Source2 This is the base Setup measurement which does not include slew rate derating Slew rate derating tables can be found in the applicable JEDEC specification This measurement is identical to the basic Setup measurement except that instead of using the Mid reference voltage for determining edge times it uses the High and Low reference voltages for the Data The Mid reference level is still used for the Strobe DQS For more details on the reference voltage setup refer to DDR Setup Hold Reference Levels Differential DOS see page 192 The application calculates this measurement using the following equation Senp _ phbin _ pnd 1 R T Where T Setup is the setup time T Main is the Main input strobe or DQS crossing time of VRefMid in the specified direction T 2nd is the 2nd input data or DQ crossing time of VRefLowFal
76. E ALIGNment DPOJET PLOT lt x gt EYE ALIGNment Sets or returns eye alignment state for eye plots Syntax DPOJET PLOT lt x gt EYE ALIGNment Inputs AUTO LEFT CENter Outputs AUTO LEFT CENter NOTE Undefined for non eye plots DPOJET REPORT This set only parameter executes a DPOJET report save operation for the currently defined report configuration Syntax DPOJET REPORT Inputs EXECute DPOJET REPORT SETupconfig Turns on or off including setup configuration in reports Syntax DPOJET REPORT SETupconfig 270 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET REPORT APPhcationconfig Inputs 1 0 Outputs 1 0 DPOJET REPORT APPlicationconfig Turns on or off including complete application configuration in reports Syntax DPOJET REPORT APPlicationconfig Inputs 1 0 Outputs 1 0 DPOJET REPORT PASSFailresults Turns on or off including pass fail results in reports Syntax DPOJET REPORT PASSFai lresults Inputs 1 0 Outputs 1 0 DPOJET Jitter and Eye Diagram Analysis Tools 271 GPIB Commands DPOJET REPORT DETailedresults DPOJET REPORT DETailedresults Turns on or off including detailed results in reports Syntax DPOJET REPORT DETai ledresults Inputs 1 0 Outputs 1 0 DPOJET REPORT PLOTimages Turns on or off including detailed plot images in reports Syntax DPOJET REPORT PLOTimages Inputs 1 0 Outputs 1 0 DPOJET REPOR
77. EE EEE OEE TEER AEE AS 284 DPOJE Ti SAY Eeiiiac fasdiet sind ere ienei e E E deer EEEE te EEE ide nn e s idene 284 DPOJEEEXPORT 2 asdeoE Rete a A aa iaaa a ia 285 DPOJET Jitter and Eye Diagram Analysis Tools ix Table of Contents X DPOJET Jitter and Eye Diagram Analysis Tools General Safety Summary General Safety Summary Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it To avoid potential hazards use this product only as specified Only qualified personnel should perform service procedures While using this product you may need to access other parts of a larger system Read the safety sections of the other component manuals for warnings and cautions related to operating the system To Avoid Fire or Personal Injury Use Proper Power Cord Use only the power cord specified for this product and certified for the country of use Connect and Disconnect Properly Do not connect or disconnect probes or test leads while they are connected to a voltage source Connect and Disconnect Properly Connect the probe output to the measurement instrument before connecting the probe to the circuit under test Connect the probe reference lead to the circuit under test before connecting the probe input Disconnect the probe input and the probe reference lead from the circuit under test before disconnecting the probe from the measurement instrument Observe All Terminal Rati
78. ER Total Jitter at a specified Bit Error Rate BER This combines the Random and Deterministic effects and predicts a peak to peak jitter that will only be exceeded with a probability equal to the BER DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table of Measurements Time Table 8 Jitter measurements definitions cont Measurement Description Jitter Summary This is not an individual measurement but a convenience function Pressing this button automatically adds a set of eleven jitter related measurements with a single action The measurements are TIE RJ RJ 66 DJ DJ 606 PJ DDJ DCD TJ BER Width BER and Phase Noise Phase Noise The RMS magnitude for all integrated timing jitter falling between two specified frequency limits This measurement is only applicable for clock signals Table of Measurements Time Definitions of the time related measurements are given in the following table Table 9 Time measurements definitions Measurement Description Rise Time Elapsed time between the Low reference level crossing and the High reference level crossing on the rising edge of the waveform Fall Time Elapsed time between the High reference level crossing and the Low reference level crossing on the falling edge of the waveform High Time Amount of time the waveform remains above the high reference voltage level Low Time Amount of time the waveform remains below the low reference vol
79. ET MEAS lt x gt RJDJ BER Sets or queries the current RJDJ BER value Syntax DPOJET MEAS x RJDJ BER Inputs NR3 Outputs NR3 DPOJET MEAS x RJDJ TYPe Sets or queries the current RJDJ measurement type DPOJET Jitter and Eye Diagram Analysis Tools 221 GPIB Commands DPOJET MEAS lt x gt RJDJ PATLen Syntax DPOJET MEAS x ENVIronment RJDJ TYPe ARBITrary REPEating Inputs ARBitrary REPEating Outputs ARBitrary REPEating DPOJET MEAS lt x gt RJDJ PATLen Sets or queries the current RJDJ pattern length Syntax DPOJET MEAS x RJDJ PATLen Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt RJDJ WINDOwlength 222 Sets or queries the current RJDJ window length Syntax DPOJET MEAS lt x gt RJDJ WINDOwlength Inputs lt NR3 gt DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt RJDJ POPUlation Outputs lt NR3 gt DPOJET MEAS lt x gt RJDJ POPUlation Sets or queries the current RJDJ population Syntax DPOJET MEAS lt x gt RJDJ POPUlation Inputs lt NR3 gt Outputs lt NR3 gt DPOJET MEAS lt x gt CLOCKRecovery METHod Sets or queries the current Clock recovery method Syntax DPOJET MEAS lt x gt CLOCKRecovery METHod STANDARD CUSTOM CONSTMEAN CONSTFIXED EXPEDGE EXPPLL CONSTMEDIAN Inputs STANDARD CUSTOM CONSTMEAN CONSTFIXED EXPEDGE EXPPLL CONSTMEDIAN Outputs STANDARD CU
80. Hysteresis Displays the threshold margin to the reference level which the voltage must cross to be recognized as changing the margin is the relative reference level plus or minus half the hysteresis use to filter out spurious events Fall High Displays the high threshold level for the falling edge of the source Fall Mid Displays the middle threshold level for the falling edge of the source Fall Low Displays the low threshold level for the falling edge of the source OK Closes the window Related Topics Measurement Configuration Summary Measurement Measurement Summary Misc Measurement Summary Misc Click Analyze gt Jitter and Eye Analysis gt Measurement Configuration Summary gt Misc tab to view various configuration parameters The Miscellaneous tab shows whether the Gating Qualify and Stat Pop Limit functions are enabled if enabled it also shows the source for qualification the size for population and various other configuration choices Measurement Off Limit By Acquistions Stop Condition Each Measurement Off Active High Ref Levels 50 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 21 Miscellaneous configuration information About Preferences Setup Item Description State Displays On when Gating Qualify and Population are enabled and Off when they are disabled Source Displays the selected source for qualify Size Specifies
81. In a histogram Deterministic Jitter DJ is bounded so that the horizontal span of the plot will remain relatively constant Random Jitter RJ is unbounded and amplitude horizontal span will continue to grow as more population is acquired The TIE histogram provides a good way to quickly and informally assess Jitter Spectrum Plot Usage A Spectrum plot is obtained from the Fourier Transform of measurement data from a Time Trend This plot is useful in identifying periodic frequency components that contribute to timing errors such as phase modulation When the signal has a repetitive data pattern an analysis of the TIE Spectrum of the signal can be used to separate Random Jitter RJ from Deterministic Jitter DJ as well as to separate subcomponents such as Periodic Jitter PJ ISI and DCD Spectral components spikes that do not correlate with the frequencies contained in the data pattern can be a clue that external deterministic noise sources are coupling into a system Data Array Plot Usage A Data Array plot shows measurement values versus measurement index where the indexes are always equally spaced along the horizontal axis In contrast the measurement values on a Time Trend plot are not equally spaced along the horizontal time axis Time Trend Plot Usage A Time Trend plot is a waveform trace of a measurement versus time Each measurement value is placed precisely at the time at which the measurement took place Measurements th
82. Inputs NORMal AVErage Outputs NORMal AVErage DPOJET PLOT lt x gt TRANSfer NUMerator Sets or returns the transfer plot numerator Syntax DPOJET PLOT lt x gt TRANSfer NUMerator Inputs MEAS1 MEAS99 Outputs MEAS1 MEAS99 NOTE Undefined for non transfer plots DPOJET PLOT lt x gt TRANSfer DENominator Sets or returns the transfer plot denominator DPOJET Jitter and Eye Diagram Analysis Tools 265 GPIB Commands Syntax DPOJET PLOT x TRANSfer DENOminator Inputs MEAS1 MEAS99 Outputs MEAS1 MEAS99 DPOJET PLOT lt x gt PHASEnoise BASEline NOTE Undefined for non transfer plots DPOJET PLOT lt x gt PHASEnoise BASEline Sets or returns the phase noise baseline Syntax DPOJET PLOT x PHASEnoise BASEline Inputs NR3 Outputs lt NR1 gt NOTE Undefined for non phase noise plots DPOJET PLOT lt x gt BATHtub VERTical SCALE 266 Sets or returns the vertical scale setting for applicable plots either Linear or Log Syntax DPOJET PLOT lt x gt BATHtub VERT1Cal SCALE DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET PLOT lt x gt BATHtub BER Inputs LINEAR LOG Outputs LINEAR LOG NOTE Undefined for non bathtub plots DPOJET PLOT lt x gt BATHtub BER Sets or returns the bathtub BER value Syntax DPOJET PLOT x BATHtub BER Inputs NR3 Outputs lt NR1
83. Jitter and Eye Diagram Analysis Tools 247 GPIB Commands DPOJET MEAS lt x gt RESULts CURRentacq STDDev DPOJET MEAS lt x gt RESULts CURRentacq STDDev Returns the standard deviation of the measurement value for the currently selected measurement for measurement slot lt x gt Syntax DPOJET MEAS x RESULts CURRentacq StdDev Outputs NR3 DPOJET MEAS lt x gt RESULts CURRentacq STDDev STATus Returns the pass fail status for the standard deviation measurement for the currently loaded limit file Set using DPOJET LIMits FILEName Syntax DPOJET MEAS x RESULts CURRentacq STDDev STATUS Outputs PASS FAIL DPOJET MEAS lt x gt RESULts CURRentacq MAX 248 Returns the maximum value of the measurement value for the currently selected measurement for measurement slot lt x gt Syntax DPOJET MEAS x RESULts CURRentacq MAX Outputs NR3 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt RESULts CURRentacq MAX STATus DPOJET MEAS lt x gt RESULts CURRentacq MAX STATus Returns the pass fail status for the max measurement for the currently loaded limit file Set using DPOJET LIMits FILEName Syntax DPOJET MEAS x RESULts CURRentacq MAX STATUS Outputs PASS FAIL DPOJET MEAS lt x gt RESULts CURRentacq MIN Returns the minimum value for the currently selected measurement for measurement slot lt x gt Syntax DPOJE
84. L you can specify the PLL type bandwidth damping factor and nominal clock offset relative to data Damping numeric input is enabled only for Type II phase locked loop Nominal Clock Offset Relative to Data To compare the reference clock times to the edge times from the data source some assumptions must be made about how they align The default assumption 1s that each data source edge is associated with the reference clock edge to which it is nearest in time This assumption may not be optimum for example if the probes for the reference clock and data signal have different cable lengths To change the way the reference clock edges and data edges are associated you can control the Nominal clock Offset Relative to Data The positive or negative time delay you specify will be used to shift the reference clock edges before the measurement software associates each data edge with the closest clock edge DPOJET Jitter and Eye Diagram Analysis Tools 103 Operating Basics Effect of Nominal Clock Offset on Eye Diagrams Jap Related Topics Effect of Nominal Clock Offset on Eye Diagrams Effect of Nominal Clock Offset on Eye Diagrams Nominal Clock Offset does not affect the eye diagrams directly Data and clock timing relationship is maintained ignoring the clock offset value The clock offset still affects the eye diagram shape indirectly through edge labeling and TIE measurement but not with alignment Bit Config for Eye Height M
85. L Standard BW PLL Model Type I Type II Type DPOJET Jitter and Eye Diagram Analysis Tools 161 Parameters Clock Recovery Parameters Option Parameters Default setting Standard b s IBA2500 2 5G PCI E 2 5G PCI E 2 5G 162 FC133 132 8M FC266 265 6M FC531 531 2M FC1063 1 063G FC2125 2 125G SerATAG1 1 5G SerATAG2 3 0 SerATAG3 6 0G USB FS 12M USB HS 480M 1394b S400b 491 5M 1394b S800b 983 0M 1394b S1600b 1 966G GB Ethernet 1 25G 100BaseT 125M OC1 51 8M OC3 155M OC12 622M OC48 2488G FC4250 4 25G FC8500 8 5G PCI E GENZ 5 0G IBA_GEN2 5 06 FBD1 3 2G FBD2 4 0G FBD3 4 8G XAUI 3 125G XAUI_GEN2 6 25G SAS15 1 5G SAS3 3 06 SAS6 6 06 RIO125 1 25G RIO250 2 5G RIO3125 3 125G Damping 1 0 5 to 2 700 m Loop BW 1 to 2 5 GHz 1 5 MHz PLL Custom BW PLL Model Type I Type Il Type I Loop BW 1 to 2 5 GHz 1 5 MHz 1 Enable only for Type Il PLL models Constant Clock Recovery Method Parameters Option Parameters Default setting Constant Clock Mean Auto Calc First Acq Every Acq First Acq Constant Clock Median Auto Calc First Acq Every Acq First Acq Constant Clock Fixed Clock Frequency 1 Hz to 25 GHz 2 5 GHz DPOJET Jitter and Eye Diagram Analysis Tools Parameters Explicit Clock Recovery Method Parameters RJDJ Analysis Parameters Only for Repeating
86. Linear Log Minimum displayed BER 1E 2 to 18 14 Applicable for Log and Linear scale only Transfer Function Plot Parameters The Transfer Function plot has the following parameters Option Parameters Default setting Vertical Scale Log Linear Log Horizontal Scale Log Linear Log Mode Normal Average Average DPOJET Jitter and Eye Diagram Analysis Tools 167 Parameters Reports Reports The Reports menu has the following command buttons B Save m Save As Option Parameters Default setting Include Setup configuration Set Clear Set Include complete application Set Clear Set configuration Include pass fail results summary Set Clear Set Include detailed results Set Clear Set Include plot images Set Clear Set Auto increment report name if Set Clear Set duplicate View report after generating Set Clear Set Report Name Browser C NTekApplicationsNDPO JETNReports 168 DPOJET Jitter and Eye Diagram Analysis Tools Reference Progress Bar Status Messages Progress Bar Status Messages Function Measurement module Status Message Description Autoset Source Autoset VertAuto Chx Vertical autoset for Chx is going on Autoset Source Autoset HorizAuto Chx Horizontal autoset for Chx is going on Autoset Source Autoset Zooming Horiz Zooming the horizontal scale after horizontal autoset Autoset Ref Level Autoset RefAuto Chx Reference level autoset for Chx is going on
87. NPercycle value used in various DDR measurements Syntax DPOJET MEAS x DDR NPERCycle Example DPOJET MEAS34 DDR NPERCycle Inputs NR3 Outputs lt NR1 gt DPOJET MEAS lt x gt DDR MPERCycle Sets or returns the MPercycle value used in various DDR measurements 282 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt DDR WINDowsize Syntax DPOJET MEAS x DDR MPERCycle Example DPOJET MEAS34 DDR MPERCyc le Inputs lt NR3 gt Outputs lt NR1 gt DPOJET MEAS lt x gt DDR WINDowsize Sets or returns the window size used in various DDR measurements Syntax DPOJET MEAS lt x gt DDR WINDOws i ze Example DPOJET MEAS34 DDR WINDOWSize Inputs NR3 Outputs lt NR1 gt DPOJET HIGHPerfrendering Sets or queries the current high performance eye rendering setting Syntax DPOJET HIGHPerfrendering DPOJET Jitter and Eye Diagram Analysis Tools 283 GPIB Commands DPOJET UNITType Inputs 1 0 Outputs lt NR1 gt DPOJET UNITType Sets or queries the current unit typesetting for DPOJET either Unit Interval or seconds Syntax DPOJET UNITType Inputs UNITinterval SEConds Outputs UNITinterval SEConds DPOJET SAVE Set only parameter saves the specified DPOJET measurement result to the specified ref For Example DPOJET SAVE MEAS4 REF2 Syntax DPOJET SAVE Inputs MEAS1 MEAS99 REF1 REF4 284 DPOJET Jitter and
88. Names C TekApplications DPOJET Logs Measurements Growse ew 2 Select the measurements that you want to log in the Select Target Measurements table on the left Click Select All to select all the measurements for logging or click Clear All to deselect the current measurements list 3 Click On Off to enable disable logging for all selected measurements 4 Click Browse to select a directory The default directory is C NTekApplicationsNDPOJETNLogsMMeasurements DPOJET Jitter and Eye Diagram Analysis Tools 43 Operating Basics 44 Table 17 Log Measurements options Item Select Target Measurements Data Logging Measurement Description Displays the measurement list Select the check box to select the measurement By default all measurements are selected Select All Selects all the measurements in the list Clear All Deselects all the measurements from the list Log Measurements Off Disables automatic logging for all selected measurements On Enables automatic logging for all selected measurements Folder Browse Saves the csv file in the specified directory The default directory is C NTekApplicationsNDPO JET Logs Measurements File Names View Displays View Log File Names see page 44 dialog View Log File Names box which lists the selected measurements with source s and their corresponding log file names in YYMMDD HHMMSS lt MeasurementName gt lt SourceName gt csv format
89. Patterns t Only for Arbitrary Patterns t Only for TIE TJQBER and Width BER measurements DPOJET Jitter and Eye Diagram Analysis Tools Option Parameters Default setting Explicit Clock Edge Explicit Clock PLL Clock Source Ch1 Ch4 Ref1 Ref4 Math1 Math4 Ch2 Clock Edge Rise Fall Both Both Clock Multiplier 1 to 10K 1 Advanced Clock Recovery Configuration Parameters Option Parameters Default setting PLL Custom BW PLL Standard BW Constant Clock Mean Constant Clock Median Nominal Data Rate Off On Off Bit Rate 1 b s to 25 Gb s 2 5 b s Known Data Pattern On Off Off Pattern Filename Browse c TekApplications DPO JET Patterns Explicit Clock Edge Nominal Clock Offset Relative to Data 1to1s 0s Explicit Clock PLL PLL Method Type I Type Il Type I Damping 0 5 to 2 700 m Loop B W 1 to 2 5 GHz 1 5 MHz Nominal Clock Offset Relative to Data 1to1s 0s RJDJ Analysis Parameters The RJDJ configure menu has the following parameters Option Parameters Default setting Data Signal Settings Pattern Type Repeating Arbitrary Repeating Pattern Length 2 Ul to 1M 2 UI Window Length t 2 to 16 UI 5 UI Population t 5 to 5000 100 Total Jitter Component BER 1E t 2 to 18 in whole numbers 12 163 Parameters Filters Parameters The Filter configure menu has the following parameters Filters Parameters Option Parameters Default setting High Pass F1 Filter Spec No Filter 1st order 2nd order 3rd order No Filter
90. QUAL i fy ACTIVE Inputs HIGH LOW Outputs HIGH LOW DPOJET POPULATION STATE Turns on or off population limits Syntax DPOJET POPULATION STATE Inputs 1 0 Outputs 1 0 DPOJET POPULATION LIMITBY Sets or queries the mechanism by limits either acquisition or population DPOJET Jitter and Eye Diagram Analysis Tools 235 GPIB Commands Syntax DPOJET POPULATION LIMITBY Inputs ACQuisitions POPUlation Outputs ACQuisitions POPUlation DPOJET POPULATION LIMIT Sets or queries the current limit value Syntax DPOJET POPULATION LIMIT Inputs lt NR3 gt Outputs lt NR1 gt DPOJET POPULATION CONDition 236 Sets or queries the current population limit condition Syntax DPOJET POPULATION CONDi tion Inputs EACHmeas LASTmeas DPOJET POPULATION LIMIT DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET LIMITRise Outputs iEACHmeas LASTmeas DPOJET LIMITRise Turns on or off the ability to limit Rise Fall measurements to transition bits only Syntax DPOJET LIMITRise Inputs 1 0 Outputs 1 0 DPOJET DIRacmodel Sets or queries the current dirac model Syntax DPOJET DIRacmode 1 Inputs FIBREchannel PCIExpress Outputs FIBREchannel PCIExpress DPOJET INTERp Sets or queries the current interpolation model DPOJET Jitter and Eye Diagram Analysis Tools 237 GPIB Commands DPOJET SOURCEAutoset Syntax
91. Results 208 m Max cc Maximum positive cycle to cycle variation m Min cc Maximum negative cycle to cycle variation Mean The application calculates the mean value using the following equation 1X Mean X X gt X XE y2 n l Standard Deviation The application calculates the standard deviation using the following equation StdDev X 0 a 5 Su X x l It may seem odd that the equation for the estimate of the Standard Deviation contains a 1 N 1 scaling factor If you knew the true mean of X and used it in place of the estimated mean X then you would in fact scale by 1 N But Xis an estimate and is likely to be in error or bias causing the estimate of the Standard Deviation to be too small if scaled by 1 N This is the reason for the scaling shown in the equation Refer to Chapter 9 2 in A Papoulis Probability Random Variables and Stochastic Processes McGraw Hill 1991 NOTE RMS value can be calculated using the relation rms mean value stddev Maximum Value The application calculates maximum value using the following equation Max X Most Positive Value of X Minimum Value The application calculates minimum value using the following equation Min X Most Negative Value of X p p The application calculates peak to peak using the following equation P p X Max X Min X DPOJET Jitter and Eye Diagram Analysis Tools Algorithms Results Population Pop
92. STATS NAME lt LIMIT gt UL lt LIMIT gt lt UL gt 0 lt UL gt lt LL gt 1 lt LL gt lt STATS gt DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics STATS STATS NAME PeakToPeak STATS NAME lt LIMIT gt UL lt LIMIT gt lt UL gt 1 lt UL gt lt LL gt 1 lt LL gt lt STATS gt lt STATS gt lt STATS_NAME gt MaxPosDe 1 ta lt STATS_NAME gt lt LIMIT gt UL lt LIMIT gt lt UL gt 1121 lt UL gt lt LL gt 1121 lt LL gt lt STATS gt lt STATS gt STATS NAME Mi nNegDe1ta lt STATS_NAME gt lt LIMIT gt UL lt LIMIT gt lt UL gt 0 lt UL gt lt LL gt 0 lt LL gt lt STATS gt lt STATS gt lt STATS_NAME gt Popu 1ation lt STATS_NAME gt lt LIMIT gt UL lt LIMIT gt lt UL gt 0 lt UL gt lt LL gt 0 lt LL gt lt STATS gt lt Measurement gt lt Main gt C ATekApplications DPOJE T Limits DPOJET Jitter and Eye Diagram Analysis Tools 57 Operating Basics About Taking a New Measurement Table 25 Limits options Item Description Pass Fail Test Off On Enables On or Disables Off the display of limit information in results Select On to choose a limits file for the selected measurement Select Limits File Browse To select an existing limits file or locate the directory Close Accepts the changes and closes the window About Taking a New Measurement If you want to change the trigger settings or localize the
93. STOM CONSTMEAN CONSTFIXED EXPEDGE EXPPLL CONSTMEDIAN DPOJET Jitter and Eye Diagram Analysis Tools 223 GPIB Commands DPOJET MEAS lt x gt CLOCK Recovery MODel DPOJET MEAS lt x gt CLOCKRecovery MODel Sets or queries the current clock recovery model Syntax DPOJET MEAS lt x gt CLOCKRecovery MODel ONE TWO Inputs ONE TWO Outputs ONE TWO DPOJET MEAS lt x gt CLOCKRecovery STAndard Sets or queries the current clock recovery standard as specified in the user interface Syntax DPOJET MEAS x CLOCKRecovery STAndard Inputs String Outputs String DPOJET MEAS lt x gt CLOCKRecovery DAMPing Sets or queries the clock recovery damping value Syntax DPOJET MEAS x CLOCKRecovery DAMPing 224 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS x CLOCKRecovery LOOPBandwidth Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt CLOCKRecovery LOOPBandwidth Sets or queries the clock recovery loop bandwidth Syntax DPOJET MEAS x CLOCKRecovery LOOPBandwi dth Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt CLOCKRecovery DATARate Turns on or off the usage of DATArate Syntax DPOJET MEAS lt x gt CLOCKRecovery DATARate Inputs 1 0 Outputs 1 0 DPOJET Jitter and Eye Diagram Analysis Tools 225 GPIB Commands DPOJET MEAS lt x gt CLOCKRecovery CLOCK Bitrate DPOJET MEAS lt x gt CLOCKRecovery CLOCkKBitrate Set
94. T AUTOincrement Turns on or off auto increment of report file names Syntax DPOJET REPORT AUTOincrement 272 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET REPORT VIEWreport Inputs 1 0 Outputs 1 0 DPOJET REPORT VIEWreport Turns on or off viewing report after generation Syntax DPOJET REPORT VIEWreport Inputs 1 0 Outputs 1 0 DPOJET REPORT REPORTName Sets the current report file name Syntax DPOJET REPORT REPORTName Inputs String Outputs String DPOJET Jitter and Eye Diagram Analysis Tools 273 GPIB Commands DPOJET LOGging SNAPshot DPOJET LOGging SNAPshot DPOJET export of the specified type either for statistics or measurements Syntax DPOJET LOGging SNAPshot STATistics MEASurements Inputs STATistics MEASurements Outputs STATistics MEASurements DPOJET LOGging STATistics STATE Turns on or off the future logging of statistics Individual measurements included in the logging are selected using the DPOJET MEAS lt x gt LOGging node This parameter turns on or off the entire set of included measurements Syntax DPOJET LOGging STATistics STATE Inputs 1 0 Outputs 1 0 DPOJET LOGging STATistics FILEname Sets or returns the current file used for statistics logging 274 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET LOGging MEASurements S TATE Syntax DPOJET LOGging STATistics FILEname Inputs Str
95. T MEAS x RESULts CURRentacq MIN Outputs NR3 DPOJET MEAS lt x gt RESULts CURRentacq MIN STATus Returns the pass fail status for the minimum measurement for the currently loaded limit file Set using DPOJET LIMits FILEName Syntax DPOJET MEAS x RESULts CURRentacq MIN STATus Outputs PASS FAIL DPOJET Jitter and Eye Diagram Analysis Tools 249 GPIB Commands DPOJET MEAS lt x gt RESULts CURRentacq PK2PK DPOJET MEAS lt x gt RESULts CURRentacq PK2PK Returns the peak to peak value for the currently selected measurement for measurement slot lt x gt Syntax DPOJET MEAS x RESULts CURRentacq PK2PK Outputs NR3 DPOJET MEAS lt x gt RESULts CURRentacq PK2PK STATus Returns the pass fail status for the peak to peak measurement for the currently loaded limit file Set using DPOJET LIMits FILEName Syntax DPOJET MEAS x RESULts CURRentacq PK2PK STATUS Outputs PASS FAIL DPOJET MEAS lt x gt RESULts CURRentacq MAXCC 250 Returns the maximum positive cycle to cycle delta of the selected measurement Syntax DPOJET MEAS x RESULts CURRentacq MAXCC Outputs lt NR3 gt DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt RESULts CURRentacq MAXCC STATus DPOJET MEAS lt x gt RESULts CURRentacq MAXCC STATus Returns the pass fail status for the max cycle to cycle measurement for the currently loaded limit file
96. The View Log File Names dialog box lists the selected measurements with source s and their corresponding log file names in YYMMDD HHMMSS lt MeasurementName gt lt SourceName gt csv format Click Close to close the dialog box DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Data Logging Measurement 0 903_130245_Period1 Ch1 csv 070903_130245_Pos Width1 Ch1 csv 070903_130245_Neg Width1 Ch1 csv Related Topics m Data Logging Statistics Data Logging Worst Case DPOJET Jitter and Eye Diagram Analysis Tools 45 Operating Basics Data Logging Worst Case Data Logging Worst Case 46 1 Click Analyze gt Jitter and Eye Analysis gt Data Logging gt Worst Case to view the Worst Case Logging screen Statistics Measurement Worst Case Folder File Names IC Tek Applications DPOJET Logs Waveforms Growse ew 2 Select the measurements which you want to log in the Select Target Measurements table on the left Click Select All to select all the measurements for logging or click Clear All to deselect the current measurements list 3 Click On Off to enable disable worst case logging for all selected measurements 4 Click Browse to select a directory The default directory is C NTekApplicationsNDPOJETNLogsNwaveforms Table 18 Log Worst Case options Item Description Select Target Measurements Displays the measurement list Select the check box to select the measurement
97. XFALL PCIEUI PCIETMINPULSE PCIEMEDMXJITTER PCIETRFMISMCH Arguments Same as syntax for measurement options Outputs NONE DPOJET CLEARALLMeas 212 This set only parameter clears the entire current list of defined measurements in DPOJET Syntax DPOJET CLEARALLMeas DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET STATE Arguments NONE Outputs NONE DPOJET STATE Returns the current measurement state of DPOJET Syntax DPOJET STATE RUN SINGLE RECALC CLEAR STOP Inputs RUN SINGLE RECALC CLEAR STOP Outputs The current state of the DPOJET measurement sequencer including any of the possible inputs DPOJET LASTError Returns the contents of the last pop up warning dialog box It returns an empty string should no error have occurred since startup or since the last call to DPOJET LASTError Syntax DPOJET LASTError Inputs STRING DPOJET Jitter and Eye Diagram Analysis Tools 213 GPIB Commands DPOJET MEAS lt x gt DPOJET MEAS lt x gt Returns the branch query for the application measurement slot with index lt x gt This will always match the measurement defined at the associated index x displayed in the DPOJET screen where index 1 is the first or top of the measurement list Branch queries will only contain the measurement branches for those branches which have measurements defined This is required because of the number of measure
98. a a a a a Height a a a nw Mask Hits a iw yw yw 78 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics About Configuring a Measurement Table 37 Amplitude measurements Clock Bit Recov Measurements Config Edges ery RJDJ Filters General Global High dl a a wv a Common Mode w w w Low Ld a a a a T nT Ratio a a a a High Low a iw a yw v V Diff Xovr nw nw a val DPOJET Jitter and Eye Diagram Analysis Tools 79 Operating Basics 80 Table 38 Standard measurements About Configuring a Measurement Clock Bit Recov Measurements Config Edges ery RJDJ Filters General Global DDR DDR Setup SE y y a a DDR Setup Diff a a a y DDR Hold SE a a a a DDR Hold Diff a a a a DDR tCK avg nw a a a DDR tCH avg a a a a DDR tCL avg a a a a DDR tERR n a a a DDR tERR m n a a vw DDR tJIT duty in a a a DDR tJIT per a a a a PCI Express 2 0 PCle T Tx w al IA Diff PP PCle T TXA a a a PCle T Tx Fall yw w a a a PCle Tmin Pulse nw a yw PCle T nT Ratio a a a in PCle T Tx Rise a v a a a PCle UI a a nw PCle Med Mx yw yw a a iw Jitter PCle T RF a a Mismch Related Topics Bit Config m Edges m Clock Recovery E RJDJ Filters General DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics About Global Global About Global This configuration tab is common for all measurements You can limit the waveform data analys
99. acting Tektronix for more information Tektronix also welcomes your feedback Click Customer feedback see page 3 for suggestions for providing feedback to Tektronix Customer Feedback Tektronix values your feedback on our products To help us serve you better please send us your suggestions ideas or other comments you may have regarding the application or oscilloscope Direct your feedback via email to techsupport tektronix com Or FAX at 503 627 5695 and include the following information General Information B Oscilloscope model number for example DPO7000 or DSA DPO70000 series and hardware options if any Software version number B Probes used DPOJET Jitter and Eye Diagram Analysis Tools Introduction to the Application Customer Feedback Application specific Information Description of the problem such that technical support can duplicate the problem If possible save the oscilloscope and application setup files as set and associated xml files m If possible save the waveform on which you are performing the measurement as a wfm file Once you have gathered this information you can contact technical support by phone or through e mail In the subject field please indicate DPOJET Problem and attach the set xml and wfm files to your e mail If there is any query related to the actual measurement results then you can generate a mht report and send it The following items are impo
100. ad einer ehe deg ign 156 Preferences Parameters 52e e Eee bau ee rr debueras reete ues eb E id erre 157 Deskew Paramietets 2 ees ioo a I uta o a e TE Ta S E O UE ES NEUE TUNES E DIROd MEE Pa dde 157 Data Logging Parameters ien niet ee ER RARE ADR ca ab lente Youd RA x densn nb eee da 158 Control Panel Paraineters oi lese eeunit aE ENEE bbeve entree dune i rtt quee Eia saei uite els 158 Configure Measurement Parameters Bit Contig Parameters sseni endie ese seu aE as sande duos SRENR ER RR ede UE Tren ERR 159 Edges Parameters aici edere eeoee o duod besten tro bep UN rera ade Ed opetp dd bv te eR eO TERR 159 Clock Recovery Parameters ecceri rininis EI bee ER T ITERATO ERE AR TRERRR ADM T RETE UTR rds 161 RJDJ Analysis Parameters cereo raten E ned ente te S Ee e quale Eod EN ER due niei 163 Falters Parameters eoeoutecec dete eor duadep ie ewe tnttecd eres pus ue bopt dud Deed a e cneunks 164 General Parameters cscs cere de nx Pas abr cuts PIA RR sta gciaaednabeced davies ORE RE Re Ne CRa n enw 164 Global Parameters dee creen etr er ein ese te Deua Pest Hp E EE dique v reci dies Pone quei eins 164 Plots Histogram Plot Parameters 00 c cece cece eee nee ene eme messe messe ehe nene 166 Eye Diagram Plot Parameters 0 0c cece eee e cence een nen nnn nnn nee En eene 166 Spectrum Plot Parameters t Lr Petre LH T ORE EE OEE 166 Time Trend Plot Parameters sss eee mene messe ee 167 Phase Noise Plot Parameters
101. age level in the direction specified The application calculates this measurement using the following equation Clock _ m lock Clock NF o oTneN d Where NPClock is the accumulated period for N clock cycles Clock js the VRefMid crossing time for the selected edge polarity If the Signal Type is Data The N Period measurement calculates the elapsed time for N consecutive unit intervals The application calculates this measurement using the following equation Data m Data Data Np 7 Daa T n n Where NP Pata is the duration for N unit intervals DPOJET Jitter and Eye Diagram Analysis Tools 177 Algorithms Positive and Negative Duty Cycle TPata js the VRefMid crossing time in either direction If T P does not exist for a given n no measurement is recorded for that position Positive and Negative Duty Cycle The Duty Cycle and Duty Cycle measurements calculate the ratio of the positive or negative portion of the cycle relative to the period The application calculates these measurements using the following equations Dt W pow D W ipo Where D is the positive duty cycle D is the negative duty cycle W 1s the positive pulse width W is the negative pulse width PClock ig the period Related Topics Period B Positive and Negative Width CC Period The CC Period measurement calculates the difference in period measurements from one cycle to the next The applicati
102. aised cosine profile and is defined in the time domain as zl eene 0 t amp t 2 i Y 1 gt t Y DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Advanced Filter Configuration Raised Cosine Ramp Function You may adjust the ramp time t by means of the Advanced control panel If you wish to turn off the ramp function set the ramp time to 0 Similarly you may adjust the blanking duration t by means of the Advanced control panel Setting the blanking duration to 0 will allow you to see the entire filtered measurement including any transients Both the ramp time t and the blanking duration t are set relative to the reciprocal of the lowest filter frequency F By default both of these parameters are set to 1 F Since they are normalized to the filter frequency they will automatically adjust if you change the filter cut off frequency The complete set of signal processing options together with representative waveforms that suggest how the options affect the measurement vector are shown here DPOJET Jitter and Eye Diagram Analysis Tools 91 Operating Basics Advanced Filter Configuration Unfiltered Measurement Filtered Measurement 92 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics About Clock Recovery Table 46 Advanced filter configuration options Item Description Ramp Time Duration of the raised cosine smoothing function applied to the measurement vector before the
103. aking PCI Express measurements PCIe T Tx Rise and PCIe T Tx Fall Jitter and Eye Diagram Analysis Tools Coua x Fall1 Mahi oe Bit Type PCle T Tx Riset V Mathi Transition Non Transition Table 57 Bit Config for PCI Express measurements Item Description Bit Type All Bits Analysis includes both transition and non transition bits Transition Analysis only on transition bits Non Transition Analysis only on non transition bits About RJ DJ This configuration tab allows you to select an appropriate decomposition method for jitter analysis RJ DJ decomposition analysis breaks the timing jitter into various categories and uses the results to predict the total jitter at a selected bit error rate BER The RJ DJ tab is present for the RJ DJ PJ DCD DDJ RJ 66 DJ 66 TJ BER and Width BER measurements The DPOJET application offers two methods of RJ DJ analysis B A method based on spectral analysis that is appropriate for cyclically repeating data patterns B A method that works for arbitrary data sequences Related Topics RJDJ Analysis of Arbitrary Pattern m RJDJ Analysis of Repeating Pattern DPOJET Jitter and Eye Diagram Analysis Tools 107 Operating Basics RJ DJ Analysis of Repeating Pattern RJ DJ Analysis of Repeating Pattern This method of RJ DJ analysis uses a Fourier transform of the time interval error signal to identify and separate jitter components It is described in the Fibre Channel Met
104. al portion of the unit interval UI for low data bits with configuration options matching those of the High measurement High Low Difference between the mean value of the High measurement and the mean value of the Low measurement Common Mode Common mode voltage for the two Mean Sourcel sources 2 T nT Ratio Ratio of the transition eye voltage to the nearest subsequent non transition eye voltage expressed in decibels V Diff Xovr Voltage level at the crossover voltage of a differential signal pair Table of Measurements Standard Measurements in the Standard category may include timing jitter amplitude or eye measurements Generally they are measurements that have been modified to support a specific standard or otherwise deviate from the generic measurements Use the Standard drop down list to view the DDR and the PCI Express measurements Their definitions are given in the following table Table 12 Standard measurements definitions Measurement Description DDR DDR Setup SE Elapsed time between the designated edge of a data waveform and that of a single ended DQS waveform based on their respective DDR specific reference level crossings DDR Setup Diff Elapsed time between the designated edge of a data waveform and that of a differential DQS waveform based on their respective DDR specific reference level crossings DDR Hold SE Elapsed time between the designated edge of a
105. all Vang 77 T eg TJ RX4 4 Vag max 4p gi 2 Low Rise Vag Max C alui uu ELS PELLE LLL LEE LLL S Low Fall For both the Strobe channel Source and the Data channel Source2 the reference levels are mapped to the source configuration panel as follows ES S 194 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms DDR Setup and Hold Measurements Typical values for the reference levels for some current technologies can be found here m DDR2 400 DDR2 533 Reference Levels see page 195 m DDR2 667 DDR2800 Reference Levels see page 195 m DDR3 800 through DDR3 1600 Reference Levels see page 196 DDR2 400 DDR2 533 Reference Levels The following reference levels are typical for single ended signals in DDR2 400 and DDR2 533 technologies The best levels depend on many variables including the supply voltage probe point and any spec amendments so use this information only for general guidance DDR2 667 DDR2 800 Reference Levels The following reference levels are typical for single ended signals in DDR2 667 and DDR2 800 technologies DPOJET Jitter and Eye Diagram Analysis Tools 195 Algorithms DDR Setup SE The best levels depend on many variables including the supply voltage probe point and any spec amendments so use this information only for genera
106. an use the PLL Model list box to choose between a Type I and Type II loop A Type I loop has a transfer function that approaches zero frequency with a slope of 1 s and a Type II loop approaches zero frequency with a 1 s2 slope In much of the PLL literature these terms are used interchangeably with First Order and Second Order loops For a thorough discussion of loop type versus order see Frequency Synthesis by Phase Lock by William Egan NOTE Although it is possible to configure a Type II PLL with a bandwidth up to 1 10 of the baud rate such a loop will have poor dynamic performance This is because Type II loops have less phase margin than Type I loops A preferred alternative to using a Type II PLL with a high bandwidth is to use a 2nd order high pass measurement filter to emulate the effects of the PLL Jitter and Eye Diagram Analysis Tools Method Apply to IPLL Custom Bw PLL Model ES 1 5MHz Table 51 PLL Custom clock recovery options Item Description PLL Model Selects between Type or Type II phase locked loop Damping Use the keypad to specify the damping ratio of the PLL It is enabled only for Type Il phase locked loop Loop BW Explicitly sets the loop bandwidth of the clock recovery PLL Apply to All Apply Applies the current clock recovery configuration to all selected measurement s that have Clock Recovery as configuration tab Advanced Displays the Clock Recovery Advanced Setup For
107. at involve two timing points are placed at the midpoint between those two time For example a Risetime measurement is placed halfway between the low threshold crossing and the high threshold crossing A Time Trend plot is useful for example in determining if the embedded clock in a serial bit stream is modulated outside the capabilities of your receiver to recover the clock If the TIE time trend plot starts to take an unexpected periodic shape then this could indicate that you have uncorrelated periodic jitter from crosstalk or from power supply coupling Bathtub Plot Usage A Bathtub curve is the industry standard way of viewing the statistical Jitter Eye Opening A Bathtub curve represents eye opening as a function of the BER Bit Error Ratio Most serial standards call for Total Jitter to be measured at a BER of 10 12 The eye opening represented by the Bathtub Curve is what is left of the unit interval after the total jitter measurement is subtracted The Jitter Eye opening and the Total Jitter have the following relationship Total Jitter Jitter Eye Opening 1 Unit Interval DPOJET Jitter and Eye Diagram Analysis Tools 127 Operating Basics Plot Usage 128 The Bathtub Curve plot shows the eye opening and total jitter values as functions of the BER level The plot is obtained from jitter analysis that performs RJ DJ separation 15 Bit error rate Log o 0 25 0 5 0 75 1 0 Time Fraction of a Unit Interval Phase Nois
108. at which time every measurement will have exactly the limit Last Measurement Sequencing continues and all measurements continue accumulating until the last slowest accumulating measurement reaches the limit at which time they all stop When sequencing stops all measurements except one may have higher population than the limit Limit Specifies the number of acquisitions or measurements the application takes before sequencing stops OK Accepts the changes and closes the window General This configuration tab allows you to customize the measurement name and qualify the measurement within a selected result range The General tab looks the same for all the measurements but is not common The values are different for different measurements You can set the custom name per measurement here Use the virtual keyboard to enter the measurement name of your choice Measurements selected in DDRA are the custom names for the measurements defined in DPOJET A tool tip displays the custom name and the DPOJET based measurement name in brackets on moving the mouse over the row in the measurement table results data snapshot and measurement configuration summary Jitter and Eye Diagram Analysis Tools Measurement Source s Data Eye Width papos tDH Diff base pos po tDOSH pos tDOSL pos General DS Diff base Global Table 44 General options Item Off Measurement Range Limits Max Value Min Value 80
109. aying the statistics Max cc Lists the maximum cycle to cycle differences per acquisition Min cc Lists the minimum cycle to cycle differences per acquisition PN Click to view Save Current Stats View Result Summary View Result Details Export to Ref Waveform View Plot Options Summary and Display Units Absolute options Save Current Stats Saves the current statistics as log information View Results Summary Displays the summary of the results for all acquisitions View Results Details Displays the detailed results specifying values for High Limit Low Limit Pass Fail and current acquisition Export to Ref Waveform Exports time trend data of the selected measurement to the reference memory Display Units Absolute Default display unit is Absolute iJ Click to view the result details t Jitter measurements such as RJ DJ show population in terms of acquisitions NOTE For Mask Hits measurement only Mean Max Min and Population values are displayed in the results table On clicking Hits in Segment 1 Segment 2 and Segment 3 are displayed For Mask Hits measurements mean indicates the total number of hits for all acquisitions The results tab with limits turned on is as follows DPOJET Jitter and Eye Diagram Analysis Tools 121 Operating Basics Viewing Statistical Results Jitter and Eye Diagram Analysis Tools Refi 9 9790ns PARTI UT 9 927 ns 112 24ps 0089
110. bits only When selected determines whether Rise Time and Fall Time measurements are performed on all bit or only on transition bits DPOJET Jitter and Eye Diagram Analysis Tools 53 Operating Basics 54 Item Enable high performance eye rendering Preferences Measurement Description When enabled determines whether eye diagrams are optimized for speed or fidelity When disabled all unit intervals UI in the waveform s are included in the rendered eye This gives the highest fidelity eye rendering but can take considerable amount of time for long records When this option is checked a statistically representative subset of the UI is rendered so that eye diagrams for long waveforms can be displayed in a shorter time The rules for high performance rendering are as follows 1 If the waveform contains 15 000 or fewer UI all the Uls in the waveform are rendered 2 If the waveform includes more than 15 000 UI it is subdivided into segments of 2000 UI each The entire waveform is scanned to find the specific UI that are the worst case violators for six different points around the eye For each of these worst case violators the entire segment of 2000 UI in which it lies is rendered Depending on whether multiple worst case violators lie in the same segment or not as few as 2000 UI but typically from 8000 to 12 000 UI will be rendered in the final eye Dual Dirac Model When selected determines which parameter extracti
111. cation selects a single source from the active sources using the following priority B st Lowest numbered Math m 22d Lowest numbered Channel B 3rd Lowest numbered Ref The results and plots are generated for a single sequence Case 4 Three sources are active The application checks whether one of the active sources is a Math which is defined as difference of two sources Example Math1 Refl Ref2 The application selects the Math waveform as the source for all single source jitter measurements The results and plots are generated for a single sequence If one of the active sources is not a Math the application selects a single source from the active sources using the following priority E s Lowest numbered Math m 2nd Lowest numbered Channel m 3rd Lowest numbered Ref The application creates single source jitter measurements The results and plots are generated for a single sequence Case 5 Four or more sources are active If four or more sources are active the application selects a single source from the active sources using the following priority m 1st Lowest numbered Math DPOJET Jitter and Eye Diagram Analysis Tools 23 Operating Basics One Touch Jitter m 22ni owest numbered Channel B 3rd Lowest numbered Ref The application creates single source jitter measurements for the selected source The results and plots are generated for a single sequence The following figure shows the summary plot after One Touch J
112. ccess oscilloscope functions the DPOJET control windows may be replaced by the oscilloscope control windows or by the oscilloscope graticule You can access oscilloscope functions in the following ways DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Saving a Setup From the menu bar on the oscilloscope choose Analyze gt Jitter And Eye Analysis gt Select B Alternatively you can switch between recently used control panels using the forward or backward arrows 3 on the right corner of the control panel Saving a Setup The DPOJET application state 1s automatically saved along with the oscilloscope state To save the oscilloscope settings and application state follow these steps 1 Click File gt Save As gt Setup 2 In the file browser select the directory to save the setup file 3 Select or enter a file name The application appends _DPOJET xm1 to store DPOJET setup and set to store oscilloscope settings 4 Click Save NOTE After the oscilloscope application is started DPOJET needs to be launched at least once before any saved DPOJET configuration can be recalled Recalling a Saved Setup To recall the default application setup and oscilloscope settings do the following steps 1 Click File gt Recall 2 Select the directory in the file browser from where you can recall the setup file 3 Selecta set file and click Recall NOTE Only set files can be selected for recall any corre
113. ce clock or explicitly by another source signal The reference clock is determined by a clock recovery process RJ Random Jitter is the statistics for all timing errors not exhibiting deterministic behavior based on the assumption that they follow a Gaussian distribution Random Jitter is typically characterized by its standard deviation RJ 66 Random Jitter as defined above but calculated based on a simplified assumption that the histogram of all deterministic jitter can modeled as a pair of equal magnitude Dirac functions impulses known as delta functions DJ Deterministic Jitter is the statistics for all timing errors that follow deterministic behavior Deterministic Jitter is typically characterized by its peak to peak value DJ 56 Deterministic Jitter as defined above but calculated on the same simplified model as described under RJ 50 PJ Periodic Jitter is the statistics for that portion of the deterministic jitter which is periodic but for which the period is not correlated with any data in the waveform DDJ Data Dependent Jitter is the statistics for that portion of the deterministic jitter directly correlated with the data pattern in the waveform DCD Duty Cycle Distortion is the statistics for that portion of the deterministic jitter directly correlated with signal polarity that is the difference in the mean timing error on positive edges versus that on negative edges TJ B
114. cription Autoset Calculates and displays the reference voltage levels for all sources where the autoset option is set according to the Autoset Ref Level Setup Setup Specifies the Base Top method and relative percent to be used for all reference voltage levels when autoset occurs Status Specifies Armed Disarmed status indicating whether the ref level voltages will be recalculated retained for a measurement If you do not perform Autoset using Autoset button the application updates the reference levels if required when you select Single or Run to take measurements 72 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Ref Levels Understanding When Ref Level Autoset will Occur When Autoset is enabled for a given source the individual reference levels are displayed but you may not manually adjust them Instead the reference levels are automatically recalculated whenever one of the following events occur B A measurement sequence is initiated for the first time after a source has become active B A measurement sequence is initiated for the first time after all results have been cleared B The Autoset button at the right edge of the panel is pressed The Autoset button is provided as a convenience but it is never required Autoset will always be run if enabled before an uninitialized source is used for a measurement An Armed indicator appears in the upper right corner of the panel whenever a new source
115. d clear horizontal eye opening at the middle reference level PCle T Tx Fall Defined as the time difference between the VRefLo 20 PCle Tmin Pulse reference level crossing and the VRefHi 80 reference level crossing on the falling edge of the waveform Defined as the single pulse width measured from one transition center to the next PCle T nT Ratio Defined as the ratio of the transition eye voltage to the nearest subsequent non transition eye voltage expressed in decibels PCle T Tx Rise Defined as the time difference between the VRefHi 80 reference level crossing and the VRefLo 20 reference level crossing on the rising edge of the waveform PCle UI For clock signals the elapsed time between consecutive crossings of the mid reference voltage level in the direction specified one measurement is recorded per crossing pair For data signals the elapsed time between consecutive crossings of the mid reference voltage in opposite directions divided by the estimated number of unit intervals for that pair of crossings one measurement is recorded per unit interval so N consecutive bits of the same polarity result in N identical period measurements PCle Med Mx Jitter PCle T RF Mismch Defined as the maximum time between the jitter median and the maximum deviation from the median Defined as the mismatch between Rise time TRise and Fall time TFall DPOJET Jitter and Eye Diagram Analysis Tools 2
116. d result can be exported to ref without selecting defining plots in the plots panel If Export Results to Ref is selected without any measurement selection an error message 2005 see page 170 is displayed If none of the selected measurements have time trend data an error message 2007 see page 170 is displayed and Export Results to Ref dialog is not displayed If the selected measurements have no results results are cleared or measurements are not run to produce results an error message 2006 see page 170 is displayed and Export Results to Ref dialog box is not displayed If the destination is none for all measurements the results are not exported to ref on clicking OK An information warning 2008 see page 170 is displayed Results as Plots 124 The application can display the results as two dimensional plots for easier analysis Before or after you take measurements you can set up the Select Plots and Plots Configure menus to define up to four plots The last plot selected is displayed when the application completes sequencing see page 119 NOTE Plots are not available for DDR tJIT duty DDR tJIT per DDR tERR n DDR tERR m n PCIe Tmin Pulse and PCle Med Mx Jitter and PCIe UI measurements If you set up plots after sequencing the application displays the plot based on the current measurement and result DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Results as Plot
117. d with a probability equal to the BER It is generally not equal to the eye width actually observed in any given acquisition A single Width BER value is determined for each acquisition by means of RJ DJ separation analysis Related Topics amp Jitter Analysis Through RJDJ Separation B Estimation of TJ gBER and Eye Width BER Eye Height 186 The Eye Height measurement is the measured minimum vertical eye opening at the UI center as shown in the plot of the eye diagram There are three types of Eye Height values The application calculates this measurement using the following equation V PYE HENGET V eyg zr Mb Voyp 10 Max Where Veye n min is the minimum of the High voltage at mid UI TIE yg Lo uax is the maximum of the Low voltage at mid UI DPOJET Jitter and Eye Diagram Analysis Tools Algorithms Mask Hits Eye Height Transition The application calculates this measurement using the following equation V eyg HEJGHT TRAN E V PYR Hr TRAN MIN T V yvy 10 TRAN MAX Where Vzyg ur TRAN MIN 1S the minimum of the High transition bit eye voltage at mid UI TIE gysg Lo rRAN MAx 18 the maximum of the Low transition bit eye voltage at mid UI Eye Height Non Transition The application calculates this measurement using the following equation V EYE HEIGHT NTRAN V vyg E NTRAN MIN V eyg 10 NTRAN MAX Where Vzyz u NrRAN uIN 1 the minimum of the High non transition bit eye voltage at mid UI TIE zyg Lo NrRAN
118. e Defines which edges on the Source1 waveform are used to take the measurement Rise Only the rising edges of the signal are used Fall Only the falling edges of the signal are used Both Both the rising and falling edges of the signal are used Configuring Edges for Phase Noise Measurements This configuration tab is displayed for Phase Noise measurements Phase noise measurements are undefined for data signals so the signal is assumed to be a clock The Noise Integration Limits determine the portion of the phase noise spectrum that is integrated to produce a single measurement per waveform acquisition Jitter and Eye Diagram Analysis Tools Item Description Active Edge Defines which edge of the source waveform is used to take measurements Rise Only the rising edges of the signal are used Fall Only the falling edges of the signal are used Both Both the rising and falling edges of the signal are used Noise Integration Limits Upper Frequency Sets the upper end of the noise integration frequency range Lower Frequency Sets the lower end of the noise integration frequency range DPOJET Jitter and Eye Diagram Analysis Tools 113 Operating Basics Configuring Edges for N Period Measurements Configuring Edges for N Period Measurements 114 This configuration tab is displayed for N Period measurements Jitter and Eye Diagram Analysis Tools Item Description Signal Type
119. e MIN Inputs NR3 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt MEASRange MAX Outputs lt NR3 gt DPOJET MEAS lt x gt MEASRange MAX Sets or queries the maximum measurement range limit value Syntax DPOJET MEAS x MEASRange MAX Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt PHASENoise LOWLimit Sets or queries the lower phase noise integration limit Syntax DPOJET MEAS lt x gt PHASENO1Se LOWLimit Inputs lt NR3 gt Outputs lt NR3 gt DPOJET MEAS lt x gt PHASENoise HIGHLimit Sets or queries the upper phase noise integration limit DPOJET Jitter and Eye Diagram Analysis Tools 231 GPIB Commands DPOJET MEAS lt x gt LOGging STATistics SELect Syntax DPOJET MEAS x PHASENOise HIGHLimit Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt LOGging STATistics SELect Sets or queries the given measurement for inclusion in any statistic logging Statistic logging is turned on or off as a whole using the DPOJET LOGging branch Syntax DPOJET MEAS x LOGging STATistics SELect Inputs 1 0 Outputs 1 0 DPOJET MEAS lt x gt LOGging MEASurements SELect 232 Sets or queries the given measurement for inclusion in any measurement logging Statistic logging is turned on or off as a whole using the DPOJET LOGging branch Syntax DPOJET MEAS x LOGging MEASurements SELect Inputs 1 0 DPOJET Jitter and E
120. e source Fall Low Sets the low threshold level for the falling edge of the source Hysteresis Sets the threshold margin to the reference level which the voltage must cross to be recognized as changing the margin is the relative reference level plus or minus half the hysteresis use to filter out spurious events OK Accepts the changes and closes the window Default setting are 90 High 50 Mid 10 Low and 3 Hysteresis About Configuring a Measurement You can configure the measurements listed under the following categories Period Freq Jitter m Time m Eye B Amplitude E Standard NOTE Configure tabs are displayed only when you select a measurement The following tables lists the configure tabs displayed for each measurement 76 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics About Configuring a Measurement Table 33 Period Freq measurements Clock Bit Recov Gen UI Name Measurements Edges Config ery RJDJ Filters eral Global Period Clock Period a a yw yw Data Period IA lA al Freq Clock a y Ld Ld Frequency Data Frequency a a a Pos Pos Width a iw a Width Neg Neg Width w al w Width N Pe N Period v Pl Va riod Duty Duty Cycle a v a nw Cycle Duty Duty Cycle In in a a Cycle CC Pe CC Period a IA w w riod CC CC Duty a a a Duty CC CC Duty nw a nw Duty Table 34 Jitter measurements Clock Bit
121. e DPOJET application can take measurements from one or two waveforms The number of waveforms used by the application depends on the type of measurement being taken Oscilloscope Setup Guidelines For all measurements use the following guidelines to set up the oscilloscope 1 The signal is any channel reference or math waveform 2 The vertical scale for the waveform must be set so that the waveform does not exceed the vertical range of the oscilloscope 3 The sample rate must be set to capture sufficient waveform detail and avoid aliasing 4 Longer record lengths increase measurement accuracy but the oscilloscope takes longer to measure each waveform Period If the Signal Type is Clock The Period measurement calculates the duration of a cycle as defined by a start and a stop edge Edges are defined by polarity threshold and hysteresis The application calculates clock period measurement using the following equation poe T n4 TT Where PClock 3s the clock period T is the VRefMid crossing time for the selected polarity If the Signal Type is Data The Period measurement calculates the duration of a Unit Interval The application calculates this measurement using the following equation p Dm L4 yK Where DPOJET Jitter and Eye Diagram Analysis Tools 175 Algorithms Positive and Negative Width PPata is the data period TPata js the VRefMid crossing time in either direction K C C is the estimated
122. e Essentials for basic timing and jitter analysis Essentials offers Period Frequency and Time Interval Error analysis Timing parametrics such as rise fall times pulse width and duty cycle Many graphical tools such as histograms time trends and spectrums Configurable HTML report generation Logging features for recording individual measurements statistics or worst case waveforms Comprehensive remote control using oscilloscope like GPIB syntax A wizard interface to ease common setup tasks Jitter and Eye Diagram Analysis Tools Advanced The Advanced configuration offers all the features of Essentials and adds the following Jitter separation RJ DJ analysis Eye measurements Amplitude measurements Measurement filters Eye diagrams bathtub plots or Mask Hits waveform plots Pass Fail limits capability Compatibility For information on oscilloscope compatibility refer to the Optional Application Software on Microsoft Windows Based Oscilloscopes Installation Manual Tektronix part number 077 0067 XX The manual is available as a PDF file DPOJET Jitter and Eye Diagram Analysis Tools Getting Started Requirements and Restrictions Requirements and Restrictions Microsoft NET Framework version 2 0 or higher MATLAB Runtime Component 7 5 is required to install and operate DPOJET on your oscilloscope Supported Probes The application supports the following probes TAPI500 m TAP2500 m TAP3500 m P5100
123. e Noise measurement performs a jitter measurement converts the result into the frequency domain and reports the rms jitter integrated between two specific frequencies selected by the user DPOJET Jitter and Eye Diagram Analysis Tools 181 Algorithms PJ PJ DDJ DCD 182 The phase noise measurement is defined only for clock signals If the source waveform appears to be a data signal a warning message will be produced but the measurement will proceed A Phase Noise measurement is required in order to enable the Phase Noise plot Periodic Jitter PJ is the peak to peak amplitude for that portion of the deterministic jitter which is periodic but for which the period is not correlated with any data pattern in the waveform A single PJ value is determined for each acquisition by means of RJ DJ separation analysis Related Topics m Jitter Analysis Through RJDJ Separation Data Dependent Jitter DDJ is the peak to peak amplitude for that portion of the deterministic jitter directly correlated with the data pattern in the waveform A single DDJ value is determined for each acquisition by means of RJ DJ separation analysis Related Topics B Jitter Analysis Through RJDJ Separation Duty Cycle Distortion DCD is the peak to peak amplitude for that portion of the deterministic jitter directly correlated with signal polarity that is the difference between the mean positive edge displacement versus that on negative edges A single DCD val
124. e Plot Usage A Phase Noise plot shows a frequency domain view of the jitter noise on a waveform normalized in an industry standard way The vertical axis is logarithmic and uses the units of dBc Hz which means decibels relative to the carrier per Hertz The horizontal axis is logarithmic with units Transfer Function Plot Usage A Transfer Function plot shows the magnitude ratio of the frequency spectrums of two measurements on logarithmic axes This can be a useful way to depict the response of a system to stimuli at various frequencies or to identify poles and zeros in a system characteristic equation Suppose that x t is a jitter measurement at the input of a device and y t is a corresponding jitter measurement at the output of the device The Transfer Function plot can be used to show the following function where X f is the Fourier Transform of x t Hip fri Epi The horizontal axis of the Transfer Function plot goes up to the Nyquist frequency of X or Y whichever is lower These plots work best if averaged across multiple acquisitions to reduce the effects of measurement noise DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Selecting Plots Waveform Plot Usage The waveform plot is only applicable to the Mask Hits measurement It depicts a copy of the source waveform with all mask violations denoted in a highlight color These are the same violations that appear on the Mask Hits eye diagram but the wavefo
125. e RJ DJ analysis 1 Available for all measurements except Mask Hits DDR tJIT duty DDR tJIT per DDR tERR n DDR tERR m n PCle Tmin Pulse PCle Ul and PCle Med Mx Jitter Available only for Phase Noise measurement Available only for all Eye TIE and PCle T TXA measurements Available only for Mask Hits measurement Available only for TJ BER and Width BER measurements You can select the measurements from the displayed measurement list table on the left The Plots for the selected measurements are displayed in Select Plots The plots which are not applicable for the selected measurement are not available under Select Plots You can select up to 4 plots a BO NN Plot Usage This section provides a description of various plots such as Histogram Time Trend Data Array Spectrum Transfer Phase Noise Eye Diagram Waveform and Bathtub Histogram Plot Usage A Histogram plot displays the results such that the horizontal axis represents the measurement values and the vertical axis represents the number of times that each value occurred Unlike most other plots a 126 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Plot Usage histogram plot can accumulate measurements over multiple acquisitions up to a total population size of 2 1 billion Histograms are particularly useful in analyzing jitter A histogram of the Time Interval Error TIE represents the basis of jitter analysis using a histogram approach
126. e Reference Waveform control window oy omo Ye NS Click On to display the waveform 7 Click to return to the application Alternatively DPOJET can also be accessed from Analyze gt Jitter and Eye Analysis gt Select In the Summary tutorial the tutorial waveforms are recalled as Math waveforms using the following setup m dplus 50gs 18g 20m patl wfm is recalled as Refi and dminus 50gs 18g 20m patl wfm as Ref2 NOTE Using Math Setup Select Math gt Math Setup in the menu bar to view the Math Setup dialog For more details refer to the Math Equation Editor Controls in your oscilloscope online help set Math1 Ref1 Ref2 Data signals m ckplus 50gs 18g 20m patl wfm is recalled as Ref3 and ckminus 50gs 18g 20m patl wfm as Ref4 NOTE Using Math Setup set Math2 Ref3 Ref4 Clock Signals Taking a Period Measurement In this lesson you will learn how to take a period measurement and view the results You can also learn the following tasks Select a measurement and a source 148 DPOJET Jitter and Eye Diagram Analysis Tools Tutorial Taking a Period Measurement Configure measurement Take measurements View results as plots or statistics View reports Return to the application Setting up a Period Measurement Follow these steps to take a period measurement 1 To set the application to default values click File gt Recall Default Setup This is not necessary if you have just s
127. e voltage level of the previous UI There are two distinct thresholds corresponding to de emphasized transitions from high to low and full swing transitions for VRefLo and VRefHi The application calculates this measurement using the following equation rid a aq Where TFall is the fall time T is the VRefLo crossing on the falling edge THi is the VRefHi crossing on the falling edge PCle Tmin Pulse PCIe Tmin Pulse minimum single pulse width Tmin Puise is measured from one transition center to the next The application calculates this measurement using the following equation TMin Pulse Vie T Where 202 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms PCIe T nT Ratio Twi Puse 1 the minimum pulse width T 1s the transition center PCle T nT Ratio PCIe T nT Ratio is based on the DPOJET measurement T nT Ratio For more details refer to the TnT Ratio see page 189 NOTE PCIe T nT Ratio measurement uses Brick Wall filter PCle T Tx Rise PCIe T Tx Rise is the time difference between the VRefHi 80 reference level crossing and the VRefLo 20 reference level crossing on the rising edge of the waveform The VRefHi and VRefLo are calculated based on the voltage level of the previous UI There are two distinct thresholds corresponding to de emphasized transitions from low to high and full swing transitions for VRefHi and VRefLo EU LAU ek al The application calculates this m
128. ean value of the first and last crossing are used as the edge event time For example if the waveform rises through the Threshold Hysteresis then rises through the Threshold then falls through the Threshold then rises through both the Threshold and the Threshold Hysteresis a single edge event occurs at the mean value of the two rising crossings DPOJET Jitter and Eye Diagram Analysis Tools 71 Operating Basics Ref Levels Example of Hysteresis on a Noisy Waveform Threshold Hysteresis r 7 Threshold rion Threshold Hysteresis Edge event time High Hysteresis Hysteresis Low E Hysteresis Automatic Versus Manual Reference Voltage Levels Each measurement source may be configured to automatically choose voltage reference levels default or to lock the reference voltages to levels of your choosing In the Ref Levels Setup panel a table at the left edge contains all of the currently active measurement sources An Autoset check box appears beside each source To enable or disable Autoset for a given source choose the source in the left column and select the corresponding check box to toggle its state For more details refer to Understanding When Ref Level Autoset will Occur see page 73 and Understanding How Ref Level Autoset Chooses Voltages see page 73 Table 30 Configure sources ref levels autoset configuration Item Des
129. ears in the control panel only when one or more plots are selected Bit Config Parameters The Eye configure menu has the following parameters Option Parameters Default setting Bit Type All Bits Transition Non Transition All Bits Mask Browser C NTekApplicationsNDPO JET Masks Measure the Center of the Bit t 1 to 10096 196 Method t Mean Mode Mean The Mask selector is available only for Mask Hits measurement t Available only for High Low and High Low measurements Edges Parameters The Edges configure menu depends on the measurement selected Edges Two Source Parameters Option Parameters Default setting Clock Edge Rise Fall Both Rise Data Edge Rise Fall Both Both Edges Phase Noise Parameters Option Parameters Default setting Active Edge Rise Fall Both Rise Noise Integration Limits Upper Frequency 0t01T 1 MHz Lower Frequency 0to 1T 0 Hz DPOJET Jitter and Eye Diagram Analysis Tools 159 Parameters 160 Edges CrossOver Parameters Edges Parameters Option Parameters Default setting Main Edge Rise Fall Both Both Edges TIE Parameters Option Parameters Default setting Signal Type Clock Data Auto Auto Clock Edge Rise Fall Both Rise Edges Skew Parameters Option Parameters Default setting From Edge Rise Fall Both Both To Edge Same as From Opposite as From Same as From Edges N Period Parameters Opt
130. easurement Syntax DPOJET MEAS x SOUrce2 Inputs CH1 CH4 MATH1 MATH4 REF1 REF4 216 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands Outputs CH1 CH4 MATH1 MATH4 REF1 REF4 DPOJET MEAS lt x gt EDGE1 Sets or queries the Sourcel edge type Syntax DPOJET MEAS lt x gt EDGE1 Inputs RISe FALL BOTH Outputs RISe FALL BOTH DPOJET MEAS lt x gt EDGE2 Sets or queries the Source2 edge type Syntax DPOJET MEAS lt x gt EDGE2 Inputs RISe FALL BOTH Outputs RISe FALL BOTH DPOJET MEAS lt x gt SIGNALType Sets the signal type for various measurements DPOJET Jitter and Eye Diagram Analysis Tools DPOJET MEAS lt x gt EDGE1 217 GPIB Commands Syntax DPOJET MEAS x SIGNALType Inputs CLOCK DATA or AUTO Outputs CLOCK DATA or AUTO DPOJET MEAS lt x gt TOEdge Sets the TOEdge value for the measurement Syntax DPOJET MEAS x TOEdge Inputs SAMEas OPPositeas Outputs SAMEas OPPositeas DPOJET MEAS lt x gt FROMedge 218 Sets the FROMedge value for the measurement Syntax DPOJET MEAS x FROMedge Inputs RISe FALL BOTH DPOJET MEAS lt x gt TOEdge DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt FILTers RAMPtime Outputs RISe FALL BOTH DPOJET MEAS lt x gt FiLTers RAMPtime Sets or queries the current filter ramp time S
131. easurement using the following equation gii sip r1 Where T Rise js the Rise time THi is the VRefHi crossing on the rising edge TLo is the VRefLo crossing on the rising edge DPOJET Jitter and Eye Diagram Analysis Tools 203 Algorithms PCIe UI PCle UI PCIe UI is based on the DPOJET measurement Period For more details refer to the Period see page 175 NOTE PCIe UI uses a 3rd order LPF with the cut off frequency of 198 kHz PCle Med Mx Jitter PCIe Med Mx Jitter is the maximum time between the jitter median and the maximum deviation from the median The application calculates this measurement using the following equation qMed Max Jitter NM TIE Where TMed Max Jitter is the median to max jitter TJitter Median js the jitter median TIE is the Time interval error PCle T RF Mismch 204 PCIe T RF Mismch Rise and Fall Time mismatch measurement is the mismatch between Rise time TRise and Fall time TF2l Rise time and Fall time are calculated using the PCIe T Tx Rise and PCIe T Tx Fall measurements The application calculates this measurement using the following equation Mismatch _ Rhe m Fail Timah abs Rie 7 Fal Where TMismatch jg the rise and fall time mismatch TRise 1s the rise time TFall is the fall time DPOJET Jitter and Eye Diagram Analysis Tools Algorithms Jitter Analysis Through RJ DJ Separation Jitter Analysis Through RJ DJ Separation Man
132. easurements This configuration tab allows you to select which waveform bit types Transition bits Non Transition or All Bits are included when taking Eye Height 104 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Bit Config for Mask Hits Measurements Jitter and Eye Diagram Analysis Tools Table 54 Bit Config for eye height Item Description Bit Type All Bits Eye analysis includes both transition and non transition bits Transition Eye analysis only on transition bits Non Transition Eye analysis only on non transition bits Bit Config for Mask Hits Measurements This configuration tab allows you to select the waveform bit type All Bits Transition or Non Transition and the mask to be used for Mask Hits measurements I Jitter and Eye Diagram Analysis Tools Mask C Tek ppkcetore DFOJET sek s PCI Express PLE_Rev20 Browse Table 55 Bit Config for mask hits Item Description Bit Type All Bits Eye analysis includes both transition and non transition bits Transition Eye analysis only on transition bits DPOJET Jitter and Eye Diagram Analysis Tools 105 Operating Basics Table 55 Bit Config for mask hits cont Item Non Transition Bit Config for Amplitude Measurements Description Eye analysis only on non transition bits Mask Browse Allows selection of the mask file If
133. en complete the result statistics is shown in the results tab The plots are displayed as shown DPOJET Jitter and Eye Diagram Analysis Tools 149 Tutorial Taking a TIE Measurement DPOJET Plots BS agana YSU AMF Periodi Time Trend NOTE You can log result statistics see page 37 measurement data points see page 38 to a csv file and worst case waveforms see page 46 to a wfm file Taking a TIE Measurement For jitter application use the PLL TIE measurement The steps to take a TIE measurement are 1 To set the application to default values click File gt Recall Default Setup This is not necessary if you have just started the application 2 Goto Select in the left navigational panel Click Jitter tab to select TIE in the Measurements area The application shows the measurement and source selection on the right of the display In this example Rt EyeTutorial wfm is recalled as Refl and is selected as source for TIE1 Jitter and Eye Diagram Analysis Tools Measurements TIE RJ T ER DJ DJ 60 Phase Noise Period Freq 3 Click or the row which lists the selected measurement to configure the source Select Refl for TIE1 For more details refer to Source Setup see page 63 150 DPOJET Jitter and Eye Diagram Analysis Tools Tutorial Taking an Eye Height and Width Measurement 4 Click Ref Levels Setup in the source configuration dialog The Configure Reflevel menu appears For more details
134. ept with the properly rated probe tips Refer to the probe manual for proper use Failure to do so may cause injury or death Refer to the General Safety Summary in your oscilloscope manual Deskewing on Oscilloscopes with Bandwidth Extension Some Tektronix oscilloscopes feature software based bandwidth extension The bandwidth extension may be enabled on a per channel basis Enabling or disabling bandwidth extension on any channel affects the skew on that channel Thus you should deskew probes and channels after you make such configuration changes Bandwidth Extension provides improved timing accuracy phase matching and amplitude accuracy It also will provide noise reduction Bandwidth extension should be used at all times Steps to Deskew Probes and Channels To deskew probes and oscilloscope channels follow these steps 1 Referto Connecting to a Device Under Test before starting the procedure 2 Connect both probes to the fastest signal in your DUT 34 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Deskew Set up the oscilloscope as follows 1 8 9 Use the Horizontal Scale knob to set the oscilloscope to an acquisition rate so that there is a minimum of two preferably five samples per edge or more samples on the deskew edge Use the Vertical Scale and Position knobs to adjust the signals to fill the display without missing any part of the signals Set the Rec
135. eric values such as reference voltage levels DPOJET Jitter and Eye Diagram Analysis Tools 11 Operating Basics Tips on DPOJET User Interface Tips on DPOJET User Interface Here are some tips to help you with the application user interface B Use the Serial Data Jitter Guide to rapidly set up and initiate sets of commonly used measurements After running the Serial Data Jitter Guide you may modify the configuration parameters to meet specific needs Select a measurement to create a measurement and add it to the current measurement table New measurements initially use the same source as the earlier measurement or the most recently used source Click ind to change the measurement source or adjust other source parameters such as the reference levels Bm Select any measurement multiple times to create multiple copies This may be useful if you wish to run the same measurement with different configuration options B Use the Single button to obtain a single set of measurements from a single new waveform acquisition Pushing the button again before processing has completed will interrupt the processing cycle m Use the Run button SD to continuously acquire and accumulate measurements Push the button again to interrupt the current acquisition B Use the Recalc button NM to perform measurements on the waveform currently displayed on the oscilloscope that is without performing a new acquisition This 1s useful if you wish t
136. ery options Item Description Nominal Data Rate Off On Enables On or disables Off the advanced clock recovery through data rate guidance Bit Rate Defines the nominal data rate in bits per second b s Use the pop up keypad to set the data rate Known Data Pattern Off On Enables On or disables Off advanced clock recovery through a known data pattern Pattern File Name Browse Selects a file to use for the data pattern OK Accepts changes and closes DPOJET Jitter and Eye Diagram Analysis Tools 97 Operating Basics About PLL Clock Recovery Setup About PLL Clock Recovery Setup When PLL based clock recovery is selected the application simulates the behavior of the hardware Phase Locked Loop clock recovery circuit This is a feedback loop in which the Voltage Controlled Oscillator VCO is used to track or follow slow variations in the bit rate of the input waveform Such loops are frequently used to recover the clock in communication links that do not transmit the clock as a separate signal The PLL parameters in the application may be adjusted to simulate with the behavior of a receiver in such a link within certain guidelines NOTE The effective transfer function of a PLL loop is not equal to the PLL Loop BW setting The Transfer function depends on the factors such as damping transition density and type PLL Standard BW 98 The PLL control area provides control over the p
137. ete reso eet oae reed ei past esa ete Odd dert eade 15 Recalling the Default Setup iccscese ierra tenter census a ee e d dna AEA DE EY ees 15 Setting Up DPOJET to Take Measurements Setting Up the Application for Analysis c cece ence eee ence eee m ee emen 16 Table of Measurements Period Freq 0 6c ccc cece nce cnet ee ee se emen een 16 Table of Measurements Jitter esses e me ee he ee enhn eese 17 Table of Measurements Time 0 e cece eee e cence ee e e e he se he he emen hene een 18 DPOJET Jitter and Eye Diagram Analysis Tools Table of Contents Table of Measurements Eye e er e e nian T Oed ede AE selena TUO Ne ee ROS 19 Table of Measurements Amplitude 00 0 ccc cee cece cece eee een eene eene messen 19 Table of Measurements Standard 00 ccc cece cee cee nee nee een n nnn e nen emen eee 20 Wizard One TOUCH SEED 22 Serial Data Jitter Guide About Serial Data Jitter Guide oi 2 seeded egeta e Ree HR E ey st AED EVI de e eda 25 Select IMMO MEE 26 Configure Measurement About Configuring Measurement 00 cece cee cece resres ee ee eee enna eee hene 27 Configure Measurement Skew ccc cece cence eee e nnn eme eese eene 27 Configure Measurement Jitter Summary 0 0 ce cece cence eee e ee eee tenet mene 28 Select SOULCES dues io e e ne does eode Padme E S nde e e PER quU EUH ooh ep vis 29 Configure Autoset Options i petia t EYE REO eO Ee FED a e
138. figuring a Transfer Plot E Configuring a Phase Noise Plot m Configuring an Eye Diagram for Mask Hits B Configuring an Eye Diagram Plot for Eye Height E Configuring a Bathtub Plot Configuring a Bathtub Plot Select a Bathtub plot in the table on the right and click Configure to configure the plot Item Description Vertical Scale Log Selects logarithmic scaling for the vertical axis Linear Selects linear scaling for the vertical axis Minimum Displayed BER 1E Sets the lower axis limit for logarithmic plots to this value expressed as the negative of a base 10 exponent OK Accepts the changes and closes the window DPOJET Jitter and Eye Diagram Analysis Tools 131 Operating Basics Configuring a Spectrum Plot Configuring a Spectrum Plot Select a Spectrum plot in the table on the right to and click Configure to configure the plot Item Description Vertical Scale Log Selects logarithmic scaling for the vertical axis Linear Selects linear scaling for the vertical axis Base Sets the lower axis limit for logarithmic plots to this value expressed as a base 10 exponent Available only when the vertical scale is log Horizontal Scale Log Selects logarithmic scaling for the horizontal axis Linear Selects linear scaling for the horizontal axis Mode Selects whether the plot shows only the most recent spectrum the uniform average of all spectrums since the last t
139. fl as source for Height and Width measurements For more details refer to Source Setup see page 63 4 Click Plots to view the available plots for the selected measurement Select Eye Diagram for Height measurement 5 Select Eye diagram Plot type and click Configure to turn on the Mask in the Configure Eye Diagram for Eye Height dialog For more details refer to the Configuring Eye Diagram Plot for Eye Height see page 136 6 Select Histogram plot for Width measurement 7 Click Single to run the application When complete the result statistics is shown in the results tab 8 The Plot summary window is displayed as shown in the following figure DPOJET Plots NOTE You can log result statistics see page 37 measurement data points see page 38 to a csv file and worst case waveforms see page 46 to a wfm file 152 DPOJET Jitter and Eye Diagram Analysis Tools Tutorial Summary Tutorial Summary Tutorial For a summary tutorial the following example is considered Case 1 Period measurement with Low pass filters to show SSC profile 1 Select Analyze gt Jitter and Eye Analysis gt Select to run the DPOJET application For more details on waveforms recalled on Math1 Refer Recalling a Waveform File see page 148 Select Period measurement on Mathl Click Configure In the Filters configuration tab select 2 4 order low pass filter and specify the cut off frequency as 33kHz F2 Fhaua
140. form is processed Edges General Table 40 Global Qualify options Item Description Off Disables the application from using the defined conditions while taking measurements On Enables the application to use the defined conditions while taking measurements Configure Displays the Qualify with Logic see page 82 dialog box 82 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Configuring Qualify with Logic Configuring Qualify with Logic DPOJET Jitter and Eye Diagram Analysis Tools 83 Operating Basics Population Table 41 Qualify Configure options Item Description Source Selects a waveform to qualify the signal or clock source used for the measurement The input source waveforms or files are Ch Ref Math and Search see page 84 Displays the burst control type selected in DDRA when you turn on the qualifier Also indicates that ASM is turned on Mid Shows the vertical reference level of the qualifier waveform t Hysteresis Shows the amount of hysteresis applied to the vertical reference level of the qualifier waveform Hysteresis prevents small amounts of noise in a waveform from producing multiple threshold crossings Active High t Enables measurements in regions t where the qualifier waveform exceeds the mid reference level Low t Enables measurements in regions t where the qualifier waveform falls below the mid reference level OK Accepts the
141. gt NOTE Undefined for non bathtub plots DPOJET PLOT lt x gt EYE HORizontal RESolution Sets or returns the Horizontal Eye resolution Syntax DPOJET PLOT lt x gt EYE HORizontal RESolution Inputs lt NR3 gt DPOJET Jitter and Eye Diagram Analysis Tools 267 GPIB Commands DPOJET PLOT lt x gt EYE HORizontal AUTOscale Outputs lt NR1 gt NOTE Undefined for non eye plots DPOJET PLOT lt x gt EYE HORizontal AUTOscale Sets or returns the horizontal auto scale setting Syntax DPOJET PLOT x EYE HORizontal AUTOscale Inputs 1 0 Outputs 1 0 NOTE Undefined for non eye plots DPOJET PLOT lt x gt EYE STATE Sets or returns the eye state either on or off Syntax DPOJET PLOT lt x gt EYE STATE Inputs 1 0 Outputs 1 0 268 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET PLOT lt x gt EYE MASK file NOTE Undefined for non eye plots DPOJET PLOT lt x gt EYE MASKfile Sets or returns the mask file Syntax DPOJET PLOT lt x gt EYE MASKfi le Inputs String Outputs String NOTE Undefined for non eye plots DPOJET PLOT lt x gt EYE SUPERImpose Sets or returns whether superimposed eyes are generated in eye diagrams Syntax DPOJET PLOT lt x gt EYE SUPERImpose Inputs 1 0 Outputs 1 0 NOTE Undefined for non eye plots DPOJET Jitter and Eye Diagram Analysis Tools 269 GPIB Commands DPOJET PLOT lt x gt EY
142. has been added or deleted or measurement results have been cleared This lets you know that the reference levels will be recalculated the next time either the Single or the Run button is selected If DisArmed indicator appears the displayed reference levels will be retained 1f a measurement sequence is performed with no further configuration changes Of course you can cause the reference levels to be recalculated at any time by selecting the Autoset button Understanding How Ref Level Autoset Chooses Voltages Once triggered the Reference Level Autoset function uses the following logic to determine actual voltage levels For each applicable source the Top high logic level and Base low logic level are first determined Then the High Mid and Low levels are calculated as percentages of the Top Base difference For example if the Top and Base are 2 8 volts and 0 4 volts respectively and the High percentage level is 90 this threshold would be calculated as HighThres Base High Percent Top Base 0 40 9 2 8 0 4 2 56 Click Setup to select a method used to calculate the Top and Base of the waveform and also the percentages used for the High Mid and Low thresholds for each source The Autoset Ref Levels see page 75 appears Manually Adjusting the Reference Voltage Levels Whether or not you use the application to automatically calculate the initial reference voltage levels you may need to manually change the values To set
143. hase locked loop used for clock recovery You can choose the loop bandwidth and the loop order and if a Type II loop is chosen you can specify the damping factor To set the loop bandwidth automatically based on a serial standard select PLL Standard BW as the clock recovery method From the Standard b s list box select the standard that matches your data link For example choose PCI E 2 5 to test a 2 5 Gbit second PCI Express link In this case the PLL bandwidth will be set to 1 5 MHz which is 1 1667 of the baud rate as specified in PCI Express standard You can use the PLL Model list box to choose between Type I and Type II loop A Type I loop has a transfer function that approaches zero frequency with a slope of 1 s and a Type II loop approaches zero frequency with a 1 s2 slope In much of the PLL literature these terms are used interchangeably with First Order and Second Order loops For a thorough discussion of loop type versus order see Frequency Synthesis by Phase Lock by William Egan DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics PLL Custom BW NOTE Although it is possible to configure a Type II PLL with a bandwidth up to 1 10 of the baud rate such a loop will have poor dynamic performance This is because Type II loops have less phase margin than Type I loops A preferred alternative to using a Type II PLL with a bandwidth close to its baud rate is to use a second order high pass measurement filter to em
144. her Mean or Mode V percent 1S the set of voltage samples over the selected portion percent of the unit interval ranging from 1 to 100 n is the index of a high bit a high transition bit or a high non transition bit The Low Amplitude measurement calculates the mean or mode of a selected portion of each unit interval corresponding to a 0 bit The application calculates this measurement using the following equation Volt OPlv percenr 1 Where Viow is the low amplitude measurement result OP is the selected Operation either Mean or Mode V percent iS the set of voltage samples over the selected portion percent of the unit interval ranging from 1 to 100 n is the index of a low bit a low transition bit or a low non transition bit DPOJET Jitter and Eye Diagram Analysis Tools Algorithms Common Mode Common Mode The Common Mode Voltage measurement also called DC Common Mode calculates the mean of the Common Mode voltage waveform The application calculates this measurement using the following equation Va Mean Vy i Where Vc is the common mode voltage measurement Vs urce1 kj Vsource 2 Vom pl is the common mode voltage waveform i is the sample index of common mode waveform values T nT Ratio The T nT Ratio measurement reports the amplitude ratio between transition and non transition bits The measurement calculates the ratios of all non transition eye voltages 2
145. hese levels For more details on reference level setup refer to DDR Setup Hold Reference Levels Differential DOS see page 192 The measurements with names ending in SE are appropriate if you have a single ended data strobe DQS signal This is allowed in DDR2 but not in DDR3 In this case both the clock DQS and data DQ signals use thresholds other than the mid threshold Check that the DPOJET reference levels for the strobe and data sources are set to match the proper values of VIH ac VIH dc VIL ac and VIL dc for the DDR technology that you are measuring Depending on which edges you choose to measure Rising Falling or Both you may not need to set up all of these levels For more details on the reference level setup refer to DDR Setup Hold Reference Levels Single ended DQS see page 194 DDR Setup Hold Reference Levels Differential DQS For systems with a differential DQS signal the waveform reference points for the Setup tDS and Hold tDH measurements details are as shown DOS oA Das DDR DPOJET Ref Level Ref Level Designations Designations Vinag MIN AT TT 4 ee een High Rise Vigo MIN ee deme pe wen 4 X e High Fall REF dc eee a en ee ee ee ee ee E Vig ax X1 4Ac Low Rise Viuag Max sA SS ee n eno Se eS SSS Se me terne Low Fall F
146. hich is configurable Range 200 lt N lt 1M DDR tCK avg DDR tCK avg is calculated as the average clock period across 200 cycle window The application calculates this measurement using the following equation 200 tCK avg 2 X CK IN j l Where N 200 which is configurable Range 200 lt N lt 1M DDR tERR n and DDR tERR m n DDR tERR n is defined as the cumulative error across multiple consecutive cycles from tCK avg DDR tERR m n is defined as the cumulative error across multiple consecutive predefined cycles from tCK avg The application calculates this measurement using the following equation i 7 1 ERR nper X ICK AX tCK avg j l Where n 2 for tERR 2 per n 3 for tERR 3 per n 4 for tERR 4 per DPOJET Jitter and Eye Diagram Analysis Tools 199 Algorithms DDR tJIT duty n 5 for tERR 5 per 6 lt n lt 10 for tERR 6 10 per 11 lt n lt 50 for tERR 11 50 per DDR tJIT duty DDR tJIT duty is defined as the cumulative set of the largest deviation of any single tCH from tCH avg and the largest deviation of any single tCL from tCL avg The application calculates this measurement using the following equation td T duty Minimax of JIT CH UJIT CL Where tJIT CH tCH tCH avg UIT CL tCL tCL avg Where i 1 to 200 DDR tJIT per DDR tJIT per is defined as the largest deviation of any single tCK from tCK avg The application calculates this measure
147. hodologies for Jitter and Signal Quality Specification MJSQ and has wide industry acceptance This method requires that the data signal be composed of a pattern of N bits that are repeated over and over The pattern length N must be known although it 1s not necessary to know the specific bits that make up the pattern Jitter and Eye Diagram Analysis Tools Data Signal Settings Pattern Type Pattern Length Repeating v 2n Table 58 RJ DJ analysis of repeating options Item Description Data Signal Settings Pattern Type Selects between repeating or arbitrary pattern analysis Pattern Length When the Pattern Type is set to Repeating sets the pattern length of the repetitive pattern data use for spectrum analysis RJ DJ separation Total Jitter Component BER 1E Sets the Bit Error Rate exponent thereby setting the t statistical level at which Total Jitter and Eye Opening are reported Apply To All Apply Applies the current settings to all the measurements having RJDJ configuration tab t Only available for TJ BER and Width BER measurements RJ DJ Analysis of Arbitrary Pattern When the data pattern is not repeating or is unknown a second method of RJ DJ analysis may be used It may also be used if the pattern is repeating and correlates well with the Spectral method in this case This method assumes that the effects of Inter Symbol Interference ISI only last for a few bits For exam
148. ial Data wizard for easy configuration of popular measurement sets One Touch Jitter wizard for quick jitter summaries B Accurate jitter decomposition and TJ BER estimation using industry accepted methods Comprehensive measurement statistics m Flexible measurement statistic logging and export capabilities Sophisticated graphical analysis tools such as Histograms Time Trends Eye Diagrams Spectrums Bathtub Plots and Real Time Eye diagrams with transition and non transition bit separation m Tektronix patented Programmable PLL software clock recovery E Standards specific support for clock recovery and jitter separation methods Capture and storage of worst case waveforms for subsequent analysis Thorough remote programmability using oscilloscope like syntax Five Time Free Trial You can refer to the Optional Applications Software on a Windows Based Oscilloscope Installation Manual for details on free trails which are available for all applications The manual is available on the Optional Applications Software on Windows Based Oscilloscopes DVD in the documents directory NOTE Before evaluating an application first check that your DSA DPO series oscilloscope firmware version is consistent with the version requirements mentioned in the application 5 readme file You can check the firmware version number from the oscilloscope Help drop down list About TekScope To check the application s firmware compatibility refer t
149. igure Measurement The transition to next step is represented by on the left along with selections or default values 26 DPOJET Jitter and Eye Diagram Analysis Tools DIDOUECORA UNE Meso Operating Basics _ About Configuring Measurement By default the configuration parameters are displayed for Period and Frequency TIE and Eye measurements The Configure Measurement option is available only for Skew and Jitter Summary The selection in the previous step is displayed on the left Configure Skew Measurement Configure Jitter Summary Measurement Configure Measurement Skew If you select Skew in the previous step you can configure edges by selecting the From and To edges and set the measurement limits Click Next to select the measurement sources Serial Data Jitter Wizare Related Topics m Configure Edges for Skew Measurement DPOJET Jitter and Eye Diagram Analysis Tools 27 Operating Basics Configure Measurement Jitter Summary Configure Measurement Jitter Summary If you select Jitter Summary measurement in the previous step you can set the pattern length by selecting Repeating pattern and then entering the pattern length in the text box If you have a non repeating waveform pattern or if the pattern length is unknown select Arbitrary NOTE The measurements that you select also determine the plot ty
150. ime Low Time High Time Common ModeV High Low High Low T nT Ratio PCIe T Tx Rise PCIe UI PCIe T Tx Fall and PCIe T RF Mismch the measurements versus time waveform time trend that is derived from the original oscilloscope waveform can be filtered before it is passed to the statistics and plotting subsystems DPOJET Jitter and Eye Diagram Analysis Tools 87 Operating Basics Filters F1 cutoff freq 3 dB High Pass Magnitude Frequency 3 dB Ee F2 cutoff freq Low Pass Magnitude Frequency 3 dB 1 Order 2 order Magnitude 3 Order Frequency Band Pass Filtering You can create a band pass filter by enabling both the High Pass and the Low Pass filters on a measurement The cut off frequency for the Low Pass filter must be greater than or equal to the cut off frequency for the High Pass filter You should be aware that setting the cut off frequencies close to each other may effectively filter out all of the measurement data or all but a small amount of timing noise This diagram shows the spectrum of the measurement data passed to the statistics and plotting subsystems when you use both the High Pass and the Low Pass filters Band Pass 3 dB4 F1 High Pass F2 Low Pass cutoff freq cutoff freq Magnitude Frequency High Pass filters attenuate low frequencies and filter out DC values entirely When a high pass filter is added to a period or frequency measurement the mean value of the filtered measureme
151. ime the results were cleared or the peak of the envelope of all spectrums since the last time the results were cleared Normal Shows magnitude values from the most recent acquisition Average Averages the magnitude values at each frequency Peak Hold Keeps the maximum value at each frequency OK Accepts the changes and closes the window Configuring a Time Trend Select a Time Trend plot in the table on the right and click Configure to configure the plot 132 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Configuring a Histogram Plot Item Description Vector Connects measurement points with straight lines to form a continuous waveform Bar Places a vertical bar at the horizontal position of each measurement with a height positive or negative that represents the value of that measurement a horizontal baseline represents the mean value of the Time Trend OK Accepts the changes and closes the window Configuring a Histogram Plot Select a Histogram plot in the table on the right and click Configure to configure the plot Item Description Vertical Scale Linear Selects linear scaling for the vertical axis Log Selects logarithmic scaling for the vertical axis Number of Bins DPOJET Jitter and Eye Diagram Analysis Tools 133 Operating Basics Item Resolution Configuring a Transfer Plot Description Defines resolution by the number of bins into which
152. imum of four plots can be selected at any given time DPOJET Jitter and Eye Diagram Analysis Tools 129 Operating Basics About Configuring Plots Table 62 Plot selections Item Description Plots Lists only the plots which are available for the selected measurement Click a plot icon to add the plot type to the table on the right Clear Selected Clears the selected plot from the plot table Clear All Clears all plots from the plot table Configure Allows you to adjust display options for the selected plot About Configuring Plots 130 Most plot types except Data Array and Waveform have display options that can be adjusted for each instance of the selected plot Jitter and Eye Diagram Analysis Tools Time Trent Period Ratt The steps to configure a plot are 1 Select a plot instance by clicking on a row from plot table on the right 2 Click Configure to display a pop up window with the available configuration options 3 Adjustthe configuration options and click OK to accept the changes and close the window 4 Click Show Plots in the control panel to view the configured plot NOTE The Show Plots icon appears in the control panel see page 61 only when one or more plots are defined Related Topics Configuring a Time Trend Configuring a Histogram Plot DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Configuring a Bathtub Plot m Configuring a Spectrum Plot Con
153. in 0s Custam Name _ v Table 19 Measurement configuration information Item Description Measurement Displays the measurement name Source Displays the selected source Others Displays the other configuration information related to the selected measurement OK Closes the window 48 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Related Topics B Measurement Summary Ref Levels B Measurement Summary Misc Measurement Summary Ref Levels Measurement Summary Ref Levels Click Analyze gt Jitter and Eye Analysis gt Measurement Configuration Summary gt Ref Levels to view the ref level tab This tab provides information about ref level configuration per source Displays the reference voltage levels for the high mid and low thresholds for the rising edge and for the falling edge of each active source and the hysteresis Measurement Ref Levels Table 20 Ref Level configuration information Item Description Source Displays the selected source Rise High Displays the high threshold level for the rising edge of the source Rise Mid Displays the middle threshold level for the rising edge of the source Rise Low Displays the low threshold level for the rising edge of the Source DPOJET Jitter and Eye Diagram Analysis Tools 49 Operating Basics Measurement Summary Misc Table 20 Ref Level configuration information cont Item Description
154. indow Click d to save the contents of the plot window in any of the format as a MATLAB figure format fig bmp jpg png emf tif mat and csv The steps to export a plot file are 1 Setup the plot window 2 Select to save the plot as a figure DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Printing Plots 3 4 Select the directory and enter a file name Click Save The application saves the file in C NTekApplicationsNDPOJETN images Printing Plots The steps to print a plot are 1 2 3 4 Verify that the printer is configured Set up the plot window with zoom cursors or grid functions Click amp icon in the plot details summary window The Print Preview dialog is displayed Click to set up the printing options and print a plot file NOTE You can customize the print layout using the MATLAB page setup options The DPOJET online help does not provide information on MATLAB page setup For more information refer to the MATLAB documentation About Reports You can use the Reports to configure and generate a compliance report to view later or to share with others You can also access reports using Analyze gt Jitter and Eye Analysis gt Reports You can select the option which you want to display in the report as shown in the following table C TekApplications DPOJET Reports MeasRepor mht Table 66 Report generation options Item Description Content Optio
155. inear Selects linear scaling for the vertical axis Log Selects logarithmic scaling for the vertical axis default Horizontal Scale Linear Selects linear scaling for the vertical axis Log Selects logarithmic scaling for the horizontal axis default Mode Selects whether the plot shows only the most recent spectrum or the uniform average of all spectrums since the last time the results were cleared default Normal updates the plot with current values Average averages the magnitude values at each frequency OK Accepts the changes and closes the window DPOJET Jitter and Eye Diagram Analysis Tools 135 Operating Basics Configuring a Phase Noise Plot Configuring a Phase Noise Plot Select a Phase Noise plot in the table on the right and click Configure to configure the plot Item Description Vertical Position Baseline Sets the lower axis limit for logarithmic plots to this value OK Accepts the changes and closes the window Configuring an Eye Diagram Plot for Eye Height 136 Select an Eye Diagram plot for all eye measurements other than Mask Hits in the table on the right and click Configure to configure the plot Configure Eye Di C TekApplications DPOJET Masks PCI Express PCE_Rev20_ Item Description Mask On Enables display and mask testing DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Configuring an Eye Diagra
156. ing Outputs String DPOJET LOGging MEASurements STATE Turns on or off the future logging of measurements Individual measurements included in the logging are selected using the DPOJET MEAS lt x gt LOGging node This parameter turns on or off the entire set of included measurements Syntax DPOJET LOGging MEASurements STATE Inputs String Outputs String DPOJET LOGging MEASurements FOLDer Sets or returns the current folder used for measurement logging Syntax DPOJET LOGging MEASurements FOLDer Inputs String DPOJET Jitter and Eye Diagram Analysis Tools 275 GPIB Commands DPOJET LOGging WORSTcase STATE Outputs String DPOJET LOGging WORSTcase STATE Turns on or off the future logging of worst case waveforms Individual measurements included in the logging are selected using the DPOJET MEAS lt x gt LOGging node This parameter turns on or off the entire set of included measurements Syntax DPOJET LOGging WORSTCase STATE Inputs 1 0 Outputs 1 0 DPOJET LOGging WORSTcase FOLDer 276 Sets or returns the current folder used for worst case logging NOTE Waveform filenames generated while worst case logging is on will follow the syntax of Measurement Name Source Minl wfm and Measurement Name Source Maxl wfm For example Periodl Chl Maxl wfm Period1 Chl Minl wfm Rise Timel Ch1 Maxl wfm Rise Timel Chl Minl wfm Syntax DPOJET LOGging WORSTCase FOLDer Inputs Stri
157. ing edge of the source Rise Low Sets the low threshold level for the rising edge of the source Fall High Sets the high threshold level for the falling edge of the source Fall Mid Sets the middle threshold level for the falling edge of the source Fall Low Sets the low threshold level for the falling edge of the source Hysteresis Sets the threshold margin to the reference level which the voltage must cross to be recognized as changing the margin is the relative reference level plus or minus half the hysteresis use to filter out spurious events Close Accepts the changes and closes the window Status Specifies Armed Disarmed status indicating whether the ref level voltages will be recalculated retained for a measurement If you do not update ref levels by clicking Autoset the application updates the reference levels if required when you select the Single or Run to take measurements t Default setting are 90 High 50 Mid 10 Low and 3 Hysteresis 74 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Autoset Ref Levels Autoset Ref Levels Click Setup in the Ref Level Setup screen to select a method used for calculating Top and Base of the waveform and also the percentages used for the High Mid and Low thresholds for each source The Autoset Ref Levels screen appears Table 32 Autoset ref level configuration Item Description Base Top Meth
158. ion Parameters Default setting Signal Type Clock Data Auto Auto Clock Edge Rise Fall Both Rise N 1 to 1M 6 Edge Increment 1 10K 1 Edges DCD Parameters Option Parameters Default setting Signal Type Clock Data Auto Auto Edges DDR tCH avg and DDR tCL avg Option Parameters Default setting Window Size 200 to 1M 200 Edges DDR tERR m n Option Parameters Default setting Clock Edge Rise Fall Rise Number of Periods Maximum 6 to 50 The value varies for different DDR generations For example For DDR 6 10 measurement the maximum default is 10 DPOJET Jitter and Eye Diagram Analysis Tools Parameters Clock Recovery Parameters Option Parameters Default setting Minimum 2 to 50 The value varies for each DDR generation For example For DDR 6 10 measurement the minimum default is 6 Window Size 200 to 1M 200 Edges DDR tERR n Option Parameters Default setting Clock Edge Rise Fall Rise Number of Periods 2 to 50 The value varies for each DDR generation For example For DDR tERR 7per measurement the default value is 7 Window Size 200 to 1M 200 Edges DDR tJIT per DDR tCK avg and DDRtJIT duty Option Parameters Default setting Clock Edge Rise Fall Rise Window Size 200 to 1M 200 Clock Recovery Parameters The Clock recovery configure menu depends on the clock recovery method being selected PLL Clock Recovery Method Parameters Option Parameters Default setting PL
159. is Tools Operating Basics Data Logging Statistics Save in e Reports m E 2 My Recent Documents Desktop My Computer My Network File name n easReport mht i Places Save as type Report files mht pr Cancel Data Logging Statistics The application can continuously log save to file the calculated statistics You can save the statistics to a comma separated value csv file to import into a text editor a spreadsheet or an analysis tool By default all measurements are selected You can select individual measurements by selecting the row in the table on the left The steps for logging statistics are 1 Click Analyze gt Jitter and Eye Analysis gt Data Logging gt Statistics to view the Logging Statistics screen DPOJET Jitter and Eye Diagram Analysis Tools 41 Operating Basics Statistics Measurement Worst Case CNTekApplicationsNDPOJET Loos Statistics 070903 123929 Browse Data Logging Statistics 2 Select the measurements which you want to log in the Select Target Measurements table on the left Click Select All to select all the measurements for logging or click Clear All to deselect the current measurements list 3 Click On Off to enable disable automatic logging statistics for all selected measurements 4 Click Browse to select a directory The default directory is C TekApplications DPOJET Logs Statistics Table 16 Log Statistics op
160. is by Gating Qualifying and Populating the waveform data Jitter and Eye Diagram Analysis Tools Edges Population Gating Gating allows you to focus the analysis on a specific area of the waveform bounded by a gated region which is a way to filter unnecessary information You can set up a gated region in one of the following ways Zoom Cursors Jitter and Eye Diagram Analysis Tools Edges Population General Global DPOJET Jitter and Eye Diagram Analysis Tools 81 Operating Basics Table 39 Global Gating options Qualify Item Description Off No gating occurs application takes measurements over the entire waveform Zoom Zooms the specified region of the source waveform to take measurements within the selected area The region of waveform within the zoom is analyzed Cursors Gates the waveform with Vertical cursors The region of waveform within the cursors is analyzed Qualify Qualifiers allows you to limit the application to more narrowly defined conditions before taking measurements All sources for the measurements and Qualify input must have the same Horizontal Sample Rate Record Length and Position to ensure that measurements function properly For measurements which require clock recovery such as TIE or eye measurements only the first qualified region will be measured even if multiple qualified regions are present For all other measurements the entire wave
161. is exact clock frequency will be used The clock phase will be determined by best fit NOTE Click Apply to All to apply the clock recovery configuration to all selected measurement s that have Clock Recovery as configuration tab 96 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Clock Recovery Advanced Setup Clock Recovery Advanced Setup The Advanced Clock Recovery methods are used when unusually high noise defeats normal clock recovery methods Under most normal operating conditions these methods are not required nor recommended Nominal Data Rate and Known Data Pattern are the two advanced clock recovery methods In Nominal Data Rate you can provide the nominal data rate to the clock recovery algorithm Normally the application analyzes your data and determines the nominal data rate automatically Using Nominal provides a starting point or hint to the clock recovery algorithm from which it analyzes data In Known Data Pattern the pattern is specified by using an ASCII text file containing the characters 1 and 0 The file may contain other characters spaces and tabs for formatting purposes but they will be ignored Several files for commonly used patterns are included with the application and you may use these as examples if you wish to create your own pattern files Click Browse to modify the default location for pattern files CAT ekApplicabonsNDPOUE TP altem PRBST27 be Table 49 Advanced clock recov
162. itter is performed DPOJET Plots 020r D 4Ghr 5614 0 DGHz 24 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics About Serial Data Jitter Guide About Serial Data Jitter Guide The Serial Data Jitter Guide allows you to set up configure and run a measurement without intimate knowledge about the control menus Select Analyze gt Jitter and Eye Analysis gt Wizard gt Serial Data Jitter Guide to launch the Serial Data Jitter Guide The Serial Data Jitter Wizard includes the following steps Select Measurement Configure Measurement Select Source s Configure Autoset Options Select Plots NOTE You can exit the Serial Data Jitter Wizard without affecting any settings in the DPOJET application by clicking Cancel anytime before clicking the Finish button DPOJET Jitter and Eye Diagram Analysis Tools 25 Operating Basics Select Measurement Select Measurement In this step you can select any of the listed measurements Serial Data Jitter Wizarc Which measurement would you like to make Period and Frequency Skew Time Interval Error TIE Jitter Summary includes Total Jitter TJ BER RJ DJ PJ DDJ TIE and DCD measurements and plots Eye Summary includes Height Width Width BER and Unit Interval measurements and plots By default the Period and Frequency measurement is selected Click Next to accept the measurement and proceed to Conf
163. kew The Skew measurement calculates the difference in time between the designated edge on a principle waveform to the designated edge on another waveform The closest data edge to the clock edge that falls within the range limits is used The application calculates this measurement using the following equation jt pae T2M Where T Skew is the timing skew T Main js the Main input VRefMidMain crossing time in the specified direction T 2nd js the 2nd input VRefMid2nd crossing time in the specified direction High Time The High Time Measurement is the amount of time that a waveform cycle is above the VRefHi voltage reference level The application calculates the measurement using the following equation TB e T 7 Where T High is the high time T Hi is the VRefHi crossing on the falling edge T Hi 1s the VRefHi crossing on the rising edge Low Time 184 The Low Time measurement is the amount of time that a waveform cycle is below the VRefLo voltage reference level The application calculates this measurement using the following equation DPOJET Jitter and Eye Diagram Analysis Tools Algorithms Setup low _ pio Io LU Ln I Where T Lov is the low time T Lot is the VRefLo crossing on the rising edge T Le is the VRefLo crossing on the falling edge Setup The Setup Time measurement is the elapsed time between the designated edge of a data waveform and when the clock waveform crosses its own voltage
164. l SS d 47 9ns 4 oes coe eee a ee reer ere Os 2us 4us 6us 0 aMHz amp MHz 8MHz 10MHz m Std Dev Max Min Min cc gt eeu mU mum rcm NEU ME cm Freq cht 20 831MHz 30 101kHz 20 921MHz 20 758MHz 162 85kHz 260 130 48kHz 140 99kHz NOTE None of the user specified settings are retained if you click Cancel before clicking Finish About Jitter And Eye Diagram Analysis Options Click Analyze gt Jitter And Eye Analysis to view the following options m Export Data Snapshot B Export Measurement Summary Data Logging B Preferences B Limits B Measurement Summary DPOJET Jitter and Eye Diagram Analysis Tools 33 Operating Basics Deskew m Deskew Deskew To ensure accurate results for two channel measurements and differential signals acquired on two channels it is important to first deskew the probes and oscilloscope channels before you take measurements of your DUT see page 34 The application includes an automated deskew utility that you can use to deskew any pair of oscilloscope channels NOTE To produce the best deskew results you should connect the probes to the fastest slew rate signals from your DUT Connecting to a Device Under Test DUT You can use any compatible probes or cable interface to connect between your DUT and oscilloscope WARNING 70 avoid electric shock remove power from the DUT before attaching probes Do not touch exposed conductors exc
165. l Eye diagrams with transition and non transition bits separation High and Low Pass measurement filters Selectable PLL and line edge detection and clock recovery methods Automatic reference level autoset for eye diagrams jitter and timing measurements Timing Analysis Timing analysis is the measurement of period setup hold skew and other edge to edge data timing relationships Eye Diagram Analysis Eye diagram analysis is the plotting and measurement of eye diagrams and masks Jitter Analysis Jitter Analysis is the measurement of Time Interval Error TIE advanced RJ DJ decomposition and other clock to data edge relationships DPOJET Option Levels The DPOJET application offers two different levels of features depending on how it is configured The configurations are determined by the following order codes DJE Jitter and Eye Diagram Analysis Tools Essentials DJA Jitter and Eye Diagram Analysis Tools Advanced DPOJET Jitter and Eye Diagram Analysis Tools 5 Getting Started Compatibility NOTE The application name Jitter and Eye Diagram Analysis Tools is the same for DJE and DJA However Help gt About DPOJET indicates the configured option level Save Recall is be compatible between the option levels If a setup file saved in DJA is recalled in DJE only the capabilities available in DJE will be recalled Jitter and Eye Diagram Analysis Tools Essentials You can us
166. l for falling data edges or VRefHighRise for rising data edges DDR Hold SE The DDR Hold SE measures the elapsed time between the designated edge of the single ended strobe DQS waveform and the designated edge of a data waveform The closest data edge to the clock edge that falls within the range limits is used The strobe is placed on Sourcel and the Data is placed on Source2 This is the base Hold measurement which does not include slew rate derating Slew rate derating tables can be found in the applicable JEDEC specification This measurement is identical to the basic Hold measurement except that instead of using the Mid reference voltage for determining edge times it uses the High and Low reference voltages for both the data and strobe DQS For more details on the reference voltage setup refer to DDR Setup Hold Reference Levels Single ended DOS see page 194 The application calculates this measurement using the following equation DPOJET Jitter and Eye Diagram Analysis Tools 197 Algorithms DDR Hold Diff Hbi _ pind Misi Where T Hold 1s the hold time T Main 1s the Main input strobe or DQS crossing time of VRefLowFall for falling strobe edges or VRefHighRise for rising strobe edges T 2nd is the 2nd input data or DQ crossing time of VRefHighFall for falling data edges or VRefLowRise for rising data edges DDR Hold Diff The DDR Hold Diff measures the elapsed time between the designated edge of the
167. l guidance DDR3 800 through DDR3 1600 Reference Levels The following reference levels are typical for single ended signals in DDR3 800 through DDR3 1600 technologies 925 mV 850 mV 750 mV 750 mV 650 mV 575 mV 30 mV The best levels depend on many variables including the supply voltage probe point and any spec amendments so use this information only for general guidance DDR Setup SE 196 The DDR Setup SE measures the elapsed time between the designated edge of a data waveform and when the single ended strobe DQS waveform crosses its own voltage reference level The closest data edge to the clock edge that falls within the range limits is used The strobe is placed on Sourcel and the Data is placed on Source2 This is the base Setup measurement which does not include slew rate derating Slew rate derating tables can be found in the applicable JEDEC specification This measurement is identical to the basic Setup measurement except that instead of using the Mid reference voltage for determining edge times it uses the High and Low reference voltages for both the Data and Strobe DQS For more details on the reference voltage setup refer to DDR Setup Hold Reference Levels Single ended DQS see page 194 The application calculates this measurement using the following equation T Y Fouad u JM Where T Setup is the setup time DPOJET Jitter and Eye Diagram Analysis Tools Algorithms DDR Setup
168. lated The Show Plots icon appears in the control panel whenever at least one plot is defined The Show Plots al icon appears in the control panel whenever at least one plot is defined By default all defined plots windows are grouped in a single window on the upper half of the display but the window can be moved resized or dragged to a second monitor The application includes tools to help you select which plots to view to size and position the plot windows to save plot information to use the zoom function and to use the cursors functions If your windows desktop is extended to a second monitor you can drag the plots window to the second monitor NOTE When sequencing is complete the plot window displays with the last plot selected The plot window also updates whenever you reconfigure a plot Using a Second Monitor to View Plots If your oscilloscope setup includes a second monitor that extends the Windows desktop you can select and drag the title bar of the plot window to position it in the second monitor This allows you to simultaneously display a waveform on the oscilloscope measurement results and the plot for easy viewing Toolbar Functions in Plot Windows The Plot Toolbar window includes the following functions BS amp gao amp wuWwoWolcgTeglNBRcCOGgG DPOJET Jitter and Eye Diagram Analysis Tools 139 Operating Basics Moving and Resizing plots Table 63 Plot toolbar functions Icon Functions m Expor
169. ls begin with a jitter versus BER bathtub curve either created from a full jitter analysis based on RJ DJ separation or from direct measurement of error rate versus sample point offset The two models differ in how the RJ 66 and DJ 66 values are extracted from the curve For the Fibre Channel standard values for RJ 66 and DJ 66 are chosen such that the Dual Dirac bathtub curve exactly matches the measured curve at the BER 10 5 and BER 10 9 points For the PCI Express and FB DIMM standards the bathtub curve is re plotted using a different y axis Instead of directly plotting against the log of the BER the y axis 1s converted to the Q scale The BER to Q scale transformation was designed such that Gaussian distributions are converted to straight lines with a slope that is directly related to the standard deviation of the Gaussian When using the Dual Dirac jitter measurements it is critical that you select the model that matches the applicable standard This may be configured in the DPOJET preferences which are found under Analyze gt Jitter and Eye Analysis gt Preferences on the Measurement tab Results The application calculates statistics for all selected measurements The application displays the following statistics in the Results menu m Mean B Std Dev Standard Deviation 8 Max Maximum Value Min Minimum Value m p p Peak to Peak B Population DPOJET Jitter and Eye Diagram Analysis Tools 207 Algorithms
170. lts by choosing Clear on the sequencing panel will reset the clock recovery so that both frequency and phase are optimized on the subsequent acquisition Jitter and Eye Diagram Analysis Tools mE STE Constant Clock Median Auto Calc DPOJET Jitter and Eye Diagram Analysis Tools 95 Operating Basics Constant Clock Fixed Table 48 Constant Clock Median options Item Description Auto Calc First Acq Calculates the best fit of the initial acquisition or the first acquisition after clearing results and then uses the value until you clear the results Auto Calc Every Acq Calculates the best fit for each acquisition default Apply to All Apply Applies the current clock recovery configuration to all selected measurement s that have Clock Recovery as configuration tab Advanced Displays the Clock Recovery Advanced Setup see page 96 dialog box Constant Clock Fixed This method provides a single option that controls how the clock recovery is performed the Clock Frequency With Fixed Constant Clock recovery no attempt is made to derive information about the actual data rate from the signal under test Instead the precise frequency that you specify will be used However the clock phase will be chosen so that the median difference between the recovered and measured edges is zero Jitter and Eye Diagram Analysis Tools Appty to All Method Constant Clock Fixed Frequency 2 5GHz Th
171. m for Mask Hits Item Description Off Disables display and mask testing Browse Select a mask file to import from the C NTekApplica tions DPOJET Masks directory Horizontal Scale Auto Scale When checked causes the horizontal scale to be adjusted automatically Resolution Manually sets the horizontal resolution when Auto Scale is unchecked Superimpose Reference Clock Eye if available When checked superimposes DQS eye onto the data eye diagram Ref Clock Alignment Determines how an eye diagram is positioned on the plot The position is determined by the eye reference point which is the location of overlapping recovered or explicit clock edge locations Typically the eye is located so that waveform edges are approximately at 25 and 75 of the width of the diagram This ensures that the eye opening is centered on the plot facilitating cursor measurements and mask testing Auto Determines the alignment property automatically Eye diagram is aligned automatically Auto is typically equivalent to Left Center Eye reference point is centered on the plot Center alignment is appropriate for DDR Write bursts or other signals with explicit reference clock where the clock and data signals are out of phase Left Eye reference point is positioned on the left of the plot so that eye opening is centered Left alignment is appropriate for DDR Read bursts and signals with recovered clock or ex
172. ment using the following equation tJiT per Minimax of tCK tC Kfavg Where i l to 200 DDR tCH avg DDR tCH avg is defined as the average high pulse width and is calculated across 200 cycle window of high pulses The application calculates this measurement using the following equation 200 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms PCIe T Tx Diff PP N tCH avg E tCH I N xtCK avg j l PCle T Tx Diff PP PCIe T Tx Diff PP voltage swing calculates the change in voltage level across a transition in the waveform ee fiw ff ff Lad pM 1 The application calculates this measurement using the following equation V pig p p V High Low Where Voitrp p is the differential peak to peak voltage Vign is the maximum voltage calculated between i and 1 1 point Vi is the minimum voltage calculated between i and 1 1 point i is the index of the UI bit location preceding the transition i is the index of the UI bit location after the transition PCle T TXA PCIe T TXA is based on the DPOJET measurement Eye width For more details refer to the Eye width see page 186 DPOJET Jitter and Eye Diagram Analysis Tools 201 Algorithms PCIe T Tx Fall PCle T Tx Fall PCIe T Tx Fall is the time difference between the VRefLo 20 reference level crossing and the VRefHi 80 reference level crossing on the falling edge of the waveform The VRefLo and VRefHi are calculated based on th
173. ments that can be defined in DPOJET is 99 Syntax DPOJET MEAS x DPOJET MEAS x DPOJET MEAS lt x gt NAME Returns the measurement name for the measurement in slot x Syntax DPOJET MEAS lt X gt NAME Outputs String DPOJET MEAS lt x gt CUSTomname 214 This sets or queries the custom measurement name for the measurement in slot x Syntax DPOJET MEAS x CUSTomname Inputs String DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands Outputs String DPOJET MEAS lt x gt MEASStart Sets or queries the measurement start value Syntax DPOJET MEAS x MEASStart Inputs NR3 Outputs lt NR1 gt DPOJET MEAS lt x gt EDGElIncre Sets or queries the measurement edge increment value Syntax DPOJET MEAS lt x gt EDGEIncre Inputs lt NR3 gt Outputs lt NR1 gt DPOJET MEAS lt x gt N Sets or queries the measurement N value DPOJET Jitter and Eye Diagram Analysis Tools DPOJET MEAS lt x gt MEASStart 215 GPIB Commands DPOJET MEAS lt x gt SOUrcel Syntax DPOJET MEAS lt x gt N Inputs lt NR3 gt Outputs lt NR1 gt DPOJET MEAS lt x gt SOUrce1 Sets or queries the Sourcel value Syntax DPOJET MEAS lt x gt SoOUrcel Inputs CH1 CH4 MATH1 MATH4 REF1 REF4 Outputs CH1 CH4 MATH1 MATH4 REF1 REF4 DPOJET MEAS lt x gt SOUrce2 Sets or queries the Source2 value May return NONE for single source m
174. more details refer to the Clock Recovery Advanced Setup see page 96 About Explicit Clock Recovery In Explicit Clock Recovery the reference clock is not derived from the measurement s target source at all but is instead taken from a separately identified source Since the source used for the measurement now differs from the source used to derive the reference clock selecting this type of clock recovery converts DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Explicit Clock Edge the measurement from a single source measurement to a dual source measurement The reference clock source is always shown on the right when the two sources appear in a measurement table Changing the clock recovery method back to a non explicit clock method will change the measurement back to a single source measurement Explicit Clock Edge Select Explicit Clock Edge method if you want to use the edges found in the selected clock source possibly multiplied up by an integral number If the Clock Multiplier is set to 1 the default only these edges will be used If the Clock Multiplier is set to a number N other than 1 linear interpolation will be used between each pair of actual edges to create N 1 additional reference edges The interpolated edge times combined with the actual edges give a total of N reference edge times per actual edge Jitter and Eye Diagram Analysis Tools Table 52 Explicit Clock edge options
175. n to hide unhide the Ref Levels Setup DPOJET Jitter and Eye Diagram Analysis Tools 69 Operating Basics Ref Levels Ref Levels 70 Timing measurements are based on state transition times By definition edges occur when a waveform crosses specified reference voltage levels Reference voltage levels must be set so that the application can identify state transitions on a waveform By default the application automatically chooses reference voltage levels when necessary seupt ve References References bU ET Math Math Pw Pw m BVSIETESIS The DPOJET application uses three basic reference levels High Mid and Low In addition a hysteresis value defines a voltage band that prevents a noisy waveform from producing spurious edges The reference levels and hysteresis are independently set for each source waveform and are specified separately for rising versus falling transitions There are two ways to set the reference voltage levels automatic see page 72 and manual see page 73 High Mid and Low Reference Voltage Levels The application uses three reference voltage levels High Mid and Low For most measurements the application only uses the Mid reference voltage level The Mid reference level defines when the waveform state transition occurs at a given threshold m For Rise Time and Fall Time measurements the High and Low reference voltage levels define when the waveform i
176. n 500 mV 10 V 10 V 500 mV 10 V 10 V Mode High 500 mV 10 V 10 V 500 mV 10 V 10 V T nt Ratio 8 dB 12 dB 12 dB 0 dB 12 dB 12 dB High Low 500 mV 10 V 10 V 500 mV 10 V 10 V Low 500 mV 10 V 10 V 500 mV 10 V 10 V V Diff Xovr 500 mV 10 V 10 V 500 mV 10 V 10 V Standard Measurements DPOJET Jitter and Eye Diagram Analysis Tools 173 Reference Measurement Values Measurement Range Limits Max Measurement Range Limits Min DDR 10 ns 1s 1s 0 ns 1s 1s Setup SE DDR 10 ns 1s 1s 0 ns 1s 1s Setup Diff DDR 10 ns 1s 1s 0 ns 1s 1s Hold SE DDR 10 ns 1s 1s 0 ns 1s 1s Hold Diff DDR 1 ms 1 ks 0 ns 0 ns 1 ks 0 ns tCK avg DDR 1ms 1 ks 0 ns 0 ns 1 ks 0 ns tCH avg DDR 1ms 1 ks 0 ns 0 ns 1 ks 0 ns tCL avg DDR 10 ns 1ms 1ms 10 ns 1 ms 1ms tJIT duty DDR 10 ns 1ms 1ms 10 ns 1 ms 1ms tJIT per DDR tERR n 10 ns 1 ms 1 ms 10 ns 1 ms 1 ms DDR 10 ns 1ms 1ms 10 ns 1 ms 1ms tERR m n PCle T Tx 1V 10 V 10V 1V 10V 10 V Diff PCle T TXA 1 ns 1s 0s 50 ps 1s 0s PCle T Tx 200 ns 1 ks 0s 0s 1 ks 0s Fall PCle Tmin 1 ms 1 ks 0s 0s 1 ks 0s Pulse PCle T nT 8 dB 12 dB 12 dB 0 dB 12 dB 12 dB Ratio PCle T Tx 200 ns 1 ks 0s 0s 1 ks 0s Rise PCle UI 1 ms 1 ks 0s 0s 1 ks 0s PCle Med 1 ms 1 ks 0s 0s 1 ks 0s Mx Jitter PCle T RF 1 ns 1 ks 0s 0s 1 ks 0s Mismch 174 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms About Algorithms About Algorithms Th
177. nal are used Both Both the rising and falling edges of the signal are used Configuring Edges for CC Period Duty Cycle Measurements This configuration tab is displayed for the CC Period Duty Cycle and Duty Cycle measurements These measurements are only defined for clock signals and each measurement value is evaluated over one full clock cycle fitters General Glotial DPOJET Jitter and Eye Diagram Analysis Tools 115 Operating Basics Configuring Edges for DCD Measurement Item Description Clock Edge Rise Measurements are only initiated on the Rising edges of the clock signal Fall Measurements are only initiated on the Falling edges of the clock signal Both Measurements are initiated on both the Rising and falling edges of the clock signal Configuring Edges for DCD Measurement This configuration tab is displayed for DCD measurement Jitter and Eye Diagram Analysis Toots Item Description Signal Type Clock Forces the signal type to Clock Edges are selectable Data Forces the signal type to Data Both rising and falling edges are used Auto Automatically detects whether the signal is clock or data Configuring Edges for DDR tCH avg and DDR tCL avg This configuration tab is displayed for both DDR tCH avg and DDR tCL avg Set the window size for clock measurements The measurement analysis is done on a sliding window of size 200 cycles with a step increment of 1 c
178. nd and subsequent eye voltages after one edge but before the next to their nearest preceding transition eye voltage 1st eye voltage succeeding an edge In the accompanying diagram it is the ratio of the Black voltages to the Blue voltages The results are given in dB Recovered edge times HAMA J Dy The application calculates the T nT Ratio using the following equations DPOJET Jitter and Eye Diagram Analysis Tools 189 Algorithms High Low TnT m dB Y rg HI NTRAN Ut V eye pgr TRANU following a rising edge TnT mn dB Veve to nrran Ut V grg Lo TRAN UT following a falling edge Where Veye_ He Tran 1S the High voltage at the interpolated midpoint of the first unit interval following a positive transition Vryg Lo raAN 1S the Low voltage at the interpolated midpoint of the first unit interval following a negative transition Vzyg Hut NrRAN 1S the High voltage at the interpolated midpoint of all unit intervals except the first following a positive transition Vryg Lo NrRAN 1S the Low voltage at the interpolated midpoint of all unit intervals except the first following a negative transition m is the index for all non transition UIs n is the index for the nearest transition UI preceding the UI specified by m In a time trend plot of the measurement results there is one measurement for each non transition bit in the waveform that is the black arrows in the diagram High Low 190 The High Low
179. ng DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET LIMits STATE Outputs String DPOJET LIMits STATE Turns on or off the pass fail limit system Pass fail status can be queried using the DPOJET MEAS lt x gt RESULTS node Syntax DPOJET LIMits STATE Inputs 1 0 Outputs 1 0 DPOJET LIMits FILEName Sets or returns the current limits filename Syntax DPOJET LIMits FILEName Inputs String Outputs String DPOJET DESKEW Performs a DPOJET deskew operation with the settings specified in DPOJET DESKEW DPOJET Jitter and Eye Diagram Analysis Tools 277 GPIB Commands Syntax DPOJET DESKEW EXEcute Inputs ExEcute DPOJET DESKEW REFChannel Sets or queries the reference channel used for deskew operation Syntax DPOJET DESKEW REFChanne Inputs CH1 CH4 Outputs CH1 CH4 DPOJET DESKEW REF Midlevel 278 Sets or returns the reference channel midlevel value Syntax DPOJET DESKEW REFMid level Inputs lt NR3 gt Outputs lt NR3 gt DPOJET DESKEW REFChannel DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET DESKEW REFHysteresis DPOJET DESKEW REFHysteresis Sets or returns the reference channel hysteresis value Syntax DPOJET DESKEW REFHysteresis Inputs lt NR3 gt Outputs lt NR3 gt DPOJET DESKEW DESKEWchannel Sets or queries the channel to be deskewed Syntax DPOJET DESKEW DESKEWChannel Inputs
180. ng the Application Starting the Application On the oscilloscope menu bar click Analyze gt Jitter and Eye Analysis gt Select to open the application Application Interface Menu Controls Table 3 Application Menu Controls descriptions Item Description Tab Shortcut to a menu in the menu bar or a category of menu options most tabs are short cuts Area Visual frame with a set of related options Option button Button that defines a particular command or task Field Box that you can use to type in text or to enter a value with the Keypad or a Multipurpose knob Check Boxes Use to select or clear preferences Scroll bar Vertical or horizontal bar at the side or bottom of a display area that can be used for moving around in that area Browse Displays a window where you can look through a list of directories and files Command button Button that initiates an immediate action such as Run command button ie in the control panel Virtual Keypad icon iss Click to use on screen keypad to enter alphanumeric values MP knob references a or b Virtual Keypad Identifiers that show which Multi Purpose Knob MPK may be used as an alternate means to control a parameter turn the knob on the oscilloscope front panel to adjust the corresponding parameter Also the value can be entered directly on the MPK display component E Select the icon and use the virtual keypad to enter alphanum
181. ngs To avoid fire or shock hazard observe all ratings and markings on the product Consult the product manual for further ratings information before making connections to the product Do Not Operate Without Covers Do not operate this product with covers or panels removed Do Not Operate With Suspected Failures If you suspect that there is damage to this product have it inspected by qualified service personnel Avoid Exposed Circuitry Do not touch exposed connections and components when power is present DPOJET Jitter and Eye Diagram Analysis Tools xi General Safety Summary Terms in this Manual These terms may appear in this manual A WARNING Warning statements identify conditions or practices that could result in injury or loss of life CAUTION Caution statements identify conditions or practices that could result in damage to this product or other property xii DPOJET Jitter and Eye Diagram Analysis Tools Introduction to the Application Welcome Welcome DPOJET is a jitter timing and eye analysis tool for Tektronix Performance Digital Oscilloscopes DPO7000 and DSA DPO70000 series DPOJET enables you to achieve new levels of productivity efficiency and measurement reliability on complex clock digital and serial data signals Some of the features of DPOJET are Advanced Jitter and Timing Analysis for clocks and data signals with up to 99 simultaneous measurements on 12 sources m Jitter Guide Ser
182. ns Include setup configuration Select Clear the option to include exclude the setup information like DPOJET version oscilloscope version and status in the generated report DPOJET Jitter and Eye Diagram Analysis Tools 143 Operating Basics Table 66 Report generation options cont Item Include complete application configuration About Reports Description Select Clear the option to include exclude the complete configuration details in the generated report Include summary pass fail results Select Clear the option to include exclude the pass fail status in the generated report Included detailed results Select Clear the option to include exclude the measurement result details in the generated report Include plot images Select Clear the option to include exclude the plot images like measurement plots and oscilloscope waveform in the generated report Save Options Auto increment report name if duplicate View report after generating Select Clear the option to autoincrement the report name if its already existed The autogenerated report is of YYMMDD_HHMMSS_ savedfile mht format Select this option to view the report after generation Report Name Lists the directory path where the last generated report is stored Save Saves the changes in the default report directory Manipulates the report name based on Auto increment report name if duplicate option Save As Displays the b
183. nt 00 cece cece cece nce eee eee ee nee eee esee hene nens 58 Selecting Measurement o er HER E ve FEE Se RE OSEE Ve Ko ida ebbegeter debere 58 Warning Log Notifiers 0 cece cece eee ne een eme messe ese ere ese ere eser eee 60 Navigation Panel erae is wanna caren A a aesaeihs Qeloae eating EA T eels ve A BRNO betes 60 Control Panel ices ne rtr bre TIE ERU E DR ERAT UFU TE 61 i DPOJET Jitter and Eye Diagram Analysis Tools Table of Contents SOULCES SELUDL stay deest roO SD PAM Neb E EN AA obtu Sen End A MN tele cadere eet doi rcs 63 Custom Source Name Le vosotute debate due torgunsd gne ete a e a e te T oduld eobbed d 64 Source AUtoset cuo EE Ee EEE ra ER cada SER seg dale e A MEER OE E EEOES 68 Ret Levels este ott eoe oe Melee p eee I oce BUR tute utente pete etes fepe teu n i MER tas 70 PxUnIISNSJEPTJ LL Em 75 Configuring Measurements About Configuring a Measurement 00 cece cece ce eee ence eee een eese e n 76 Global About Global ue Re teet ddan RE eU tUa ue den qe ys 81 COURIER ME 81 Quality x3 ee Ter eere Vased vue rod UE e re e E 82 Configuring Qualify with Logic me me menn 83 Popu lati n c ire ta eva po eU eS M E E quod ay dete eet edi aes Mea ated 84 Configuring Population Limit 00 ccc ccce cece cece eee need nnn nee me menn 85 Generalni et bres com eM a idt gen en dens elg UP eas ae eT dede apie Ea E E E 86 FIETS c trn P de t oS ode urere Novit edo urere n
184. nt 58 Selecting Plots 129 Sequencing 119 Serial Data Jitter Guide 25 set up 25 Setup 185 Show Plots 62 Signal Type 114 Sine x x 54 Single 62 single source 63 Skew 184 Source Autoset 68 Sources Setup 63 Spectrum 126 Spectrum Plot Parameters 166 SSC 87 Standard b s 99 Starting the Application 11 290 Stat Pop 50 Statistical Results 120 Statistics log files 13 Std Dev 121 Steps to Deskew Probes and Channels 34 Stop Conditions Each Measurement Last Measurement 86 Summary 120 Summary Measurement 48 Summary Misc 50 Summary Ref Levels 49 Sync Cursor 140 T T nT Ratio 189 T nT Ratio 20 Tab 11 Technical Support 3 text editor 60 TIE 17 Time Trend 126 Time Trend Plot Parameters 167 Timing Analysis 5 TJ 17 TJ BER 181 TJ BER and Eye Width BER 206 To Edge 112 tool tip 64 Toolbar Functions in Plot 139 Total Jitter Component 108 Transfer 126 Transfer Function Plot Parameters 167 Transition 105 Tutorial 147 two source 63 U Upper Frequency 113 V V Diff Xovr 191 Vert amp amp Horiz 69 Vertical cursors 142 Vertical Scale 132 View Log File 39 View Results Details 121 View Results Summary 121 Viewing Plots 139 virtual keypad 11 W W1011 171 W1051 171 W1053 171 Waveform 126 Waveform Files 147 Waveform Interpolation Type 54 Width 19 Width BER 19 Window Length 109 Worst Case Logging 46 Z
185. nt goes to zero This can be seen by creating a Time Trend plot of a high pass filtered period or frequency measurement Although this is the correct theoretical behavior for the filtered measurement it is not very useful if the Results panel reports that the mean period or frequency is zero For this reason the mean values that appear in the results panels for Period and Frequency measurements are the values before the filter 88 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Jitter and Eye Diagram Analysis Tools Table 45 Filter options 1kHz Brick Wall Filter Configuration E IN High Pass F1 Low Pass F2 gt Freq Filter Spec fist Order ie No Filter 7 freq tF2 Th Item Description High Pass Filter Spec When enabled blocks the low frequency band and passes only the high frequency band of the waveform defined as 1st order 2nd order 3rd order Butterworth and No filter being the default Freq F1 High Pass filter cut off frequency at which the filter magnitude falls by 3 dB Low Pass Filter Spec When enabled blocks the high frequency band and passes only the low frequency band of the waveform defined as 1st order 2 4 order 3rd order Butterworth and No filter being the default Freq F2 Low Pass filter cut off frequency at which the filter magnitude falls by 3 dB Advanced Displays the Advanced Filter Configuration see page 90 dialog box
186. number of unit intervals between two successive edges C is the calculated data bit index of T Data Each measurement result P Pata is repeated K times in the measurement result vector so that the measurement population is equal to the number of unit intervals in the qualified waveform rather than the number of edge pairs Positive and Negative Width Amount of time the waveform remains above below the mid reference voltage level The application calculates these measurements using the following equations Wy B f in T Wa ri E Ti Where W is the positive pulse width W is the negative pulse width T is the VRefMid crossing on the falling edge T 1s the VRefMid crossing on the rising edge Frequency Frequency measurement calculates the inverse of the data period for each cycle If the Signal Type is Clock The application calculates clock frequency measurement using the following equation pm 1 paws Where FClock 3s the clock frequency 176 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms N Period PClock 3s the clock period measurement If the Signal Type is Data The application calculates data frequency measurement using the following equation gmn vp Where FData is the data frequency PbPata is the data period measurement N Period If the Signal Type is Clock The N Period measurement calculates the elapsed time for N consecutive crossings of the mid reference volt
187. o E 213 IDPOJET LAST Emon rhet to EO ER PECO iad bd Tere Uhr e ROO RR PA QU A EO Ee RT aaa 213 DPOJE TV MEAS cM 214 DPOJET MEAS lt x gt FILTers HIGHPass DPOJET Jitter and Eye Diagram Analysis Tools vii Table of Contents viii DPOJET MEAS lt x gt FILTers HIGHPass SPEC 0 0 cece cece cece cnet eee eee 219 DPOJET MEAS lt x gt FILTers HIGHPass FREQ sese 220 DPOJET MEAS lt x gt FILTers LOWPass DPOJET MEAS lt x gt FILTers LOWPass SPEC 2 0 0 orrera goe AEO EE memes 220 DPOJET MEAS lt x gt FILTers LOWPass FREQ 0 cece cece ence een nent eee ene e eee eene 221 DPOJET MEAS lt x gt RIDII BER rr RH EI 221 DPOJET MEAS x CLOCKRecovery METHod ssssssssesseesseesse eee eene 223 DPOJET MEAS X gt BIT TYPE erena n A es ee tet noc E E SO DUbtM e vA hn E UE CUgR 228 DPOJET MEAS x MASKfile cssssssssssssssssessssses esee mee menses eese sese sen enne 229 DPOJET MEAS lt x gt MEASRange DPOJET MEAS lt x gt MEASRange STATE 00 e cece eee eee een Ie eme 230 DPOJET MEAS lt x gt PHASENoise LOWLimiIt 0 0 ccc ccc cece cee eee I mee 231 DPOJET MEAS lt x gt PHASENoise HIGHLimit 0 c ccc cece cece eee nee emen 231 DPOJET MEAS lt x gt LOGging DPOJET MEAS lt x gt LOGging STATistics SELect 0 0 00 ccc cece ence nee n eee eens eee en nena eens 232 DPOJET MEAS x LOGging MEASurements SELect sess 232 DPOJET MEAS l
188. o deterministic jitter Those components that fall at the frequency increment corresponding to the pattern length are identified as data dependent jitter and those occurring at other frequencies are attributed to uncorrelated periodic Jitter The remaining spectral noise floor appropriately normalized to account for the removed deterministic Jitter is integrated to predict the standard deviation of the underlying Gaussian random noise process DPOJET Jitter and Eye Diagram Analysis Tools 205 Algorithms RJ DJ Separation for Arbitrary Patterns Once the spectral components corresponding to each deterministic Jitter type have been identified each component is inverse transformed back to the time domain From these waveforms the peak to peak jitter for each component is determined For the random jitter the RMS deviation is directly computable from the standard deviation of the Gaussian model RJ DJ Separation for Arbitrary Patterns When the data pattern borne by the source waveform is not cyclically repeating any periodic jitter still has a frequency spectrum consisting of impulses but this is not true of the data dependent jitter In this case analysis of the data dependent jitter may proceed based on the assumption that any given bit is affected by a finite and relatively small number of preceding bits By averaging all events for which a given bit is preceded by a particular bit sequence the data dependent jitter attributable to that bi
189. o modify a configuration parameter and re run the measurements on the current waveform 12 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Application Directories Application Directories The installation directory for DPOJET is C Program FilesNTekApplicationsNDPOJET During installation the application sets up directories for various functions such as to save setup files The file name extension is used to identify the file type Table 4 Application directories Default directory Used for C NTekApplicationsNDPOJETNImages Exported plot files C NTekApplicationsNDPOJETNL imi ts Pass fail limits files C NTekApplicationsNDPOJETNPatterns Bit patterns C NTekApplicationsNDPOJETNLogs Log files Consists of three subfolders Statistics for statistics log files csv m Measurements for measurement log files csv and Waveforms for worst case waveforms wfm C NTekApplicationsNDPOJETMMasks Mask files for various serial data standards For Example PCIE FBDIMM SATA C NTekApplicationsNDPOJETNReports Report files mht C NTekApplicationsNDPOJET Error log file DPOJETErrors log C NTekApplicationsNDPOJETNExamples Various tutorial and support files File Name Extensions Table 5 File name extensions File Extension Description CSV Ascii file containing Comma Separated Values This file format may be read by any ascii text edit
190. o the System Requirements section of the readme txt file If an application is introduced after you receive your oscilloscope you can download the application as described in the installation manual Tektronix part number 071 1888 XX to obtain the free trial You can download the manuals from www tektronix com manuals and www tektronix com software DPOJET Jitter and Eye Diagram Analysis Tools 1 Introduction to the Application Related Documentation Related Documentation Tektronix manuals are available at www tektronix com manuals and www tektronix com software Use the following table to determine the document that you need Table 1 List of reference documents For information on Refer to Operating the Oscilloscope Oscilloscope user manual Oscilloscope user online help W Software warranty Optional Applications Software on Windows Based I Oscilloscopes Installation Manual which is provided on m Listof available applications the Optional Applications Software on Windows Based m Compatible oscilloscopes Oscilloscopes CD ROM in the Documents directory W Relevant software and firmware version numbers Applying a new option key label Installing an application m Enabling an application Downloading updates from the Tektronix Web site Conventions Online Help uses the following conventions When steps require sequence of selections using the application interface the gt delimiter marks
191. od Min Max Uses the minimum and maximum values in the waveform to determine the base and top amplitude Useful on a waveform with low noise and free from excessive overshoot Low High Histogram Full Waveform Uses a histogram approach to determine the base top amplitude Creates a histogram of the amplitudes of the entire waveform the histogram should have a peak at the nominal high level and another peak at the nominal low level Low High Histogram Center of Eye Uses a histogram approach to determine the base top amplitude Creates a histogram of the amplitudes in the center of each bit unit interval while ignoring the waveform during bit transitions The histogram should have a peak at the nominal high level and another peak at the nominal low level Auto Set Ref Level Relative to Base Top Automatically determines the best Base Top method to use DPOJET Jitter and Eye Diagram Analysis Tools 75 Operating Basics Table 32 Autoset ref level configuration cont About Configuring a Measurement Item Description Rise High Sets the high threshold level for the rising edge of the source Rise Mid Sets the middle threshold level for the rising edge of the source Rise Low Sets the low threshold level for the rising edge of the source Fall High Sets the high threshold level for the falling edge of the source Fall Mid Sets the middle threshold level for the falling edge of th
192. ols 61 Operating Basics 62 Table 28 Control panel selections Control Panel Item Description Clear Clears the current result display and resets any statistical results and autoset ref levels Recalc Runs the selected measurements on the current acquisition Single Initiates a new acquisition and runs the selected measurements Run Initiates a new acquisition and runs the selected measurements repeatedly until Stop is clicked Used only for live sources Show Plots Displays the plot summary window when clicked This button appears in the control panel only when a plot is selected DDR Analysis Shortcut to access the DDRA application from DPOJET Appears in the control panel only when DDRA is opened using Analyze DDR Analysis The control panel with Show Plots is as shown DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Sources Setup Sources Setup The application takes measurements from waveforms specified as input sources You can select an oscilloscope channel input live a reference or a math waveform as the source and also view labels of the selected waveforms You can configure sources using any of the following options B Click icon in the table which lists the selected measurements m Double click anywhere on row in the table which lists the selected measurements The source selections depend on the selected measurement For differential input so
193. olute FALLHi gh Inputs NR3 Outputs NR3 DPOJET REFLevels CH lt x gt ABsolute FALLMid Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt ABsolute FALLMid DPOJET Jitter and Eye Diagram Analysis Tools 241 GPIB Commands DPOJET REFLevels CH lt x gt ABsolute FALLLow Inputs lt NR3 gt Outputs lt NR3 gt DPOJET REFLevels CH lt x gt ABsolute FALLLow Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH x ABsolute FALLLOW Inputs NR3 Outputs NR3 DPOJET REFLevels CH lt x gt ABsolute HYSTeresis 242 Sets the hysteresis value used for autoset Syntax DPOJET REFLevels CH lt x gt ABsolute HYSTeresis Inputs lt NR3 gt Outputs lt NR3 gt DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET REFLevels CH lt x gt PERcent DPOJET REFLevels CH lt x gt PERcent Sets percent reflevel parameters work as the absolute parameters do only setting the various percentage levels used by the autoset DPOJET REFLevels CH lt x gt PERcent RISEHigh Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt PERCent RISEHigh Inputs lt NR3 gt Outputs lt NR3 gt DPOJET REFLevels CH lt x gt PERcent RISEMid Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt PERCent RISEMid
194. on Total Jitter Component t BER 1E Set the Bit Error Rate exponent thereby setting the statistical level at which Total Jitter and Eye Opening are reported Apply to All Apply Applies the current RJ DJ configuration settings to all the selected measurement s having RJ DJ configuration tab t Available only for TJ BER and Width BER measurements Configuring Edges This configuration tab allows you to select which waveform edge or edges the application will use to take each measurement Depending on the particular measurement the tab will offer access to other options and constraints that help guide the analysis The application is able to automatically detect whether a signal is clock or data and will do so by default This can be overridden by configuring the signal type as Clock or Data The following configuration options apply to most measurements See the subsequent sections for Edge tabs corresponding to particular measurements Jitter and Eye Diagram Analysts Toots 110 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Configuring Edges Item Description Signal Type Clock Forces the signal type to be interpreted as a Clock Measurements will take place on the edges specified by the Clock Edge control Data Forces the signal to be interpreted as a Data Both rising and falling edges are used Auto Allows the application to automatically detect whether the signal is
195. on method is used when RJ DJ separation is done under the Dual Dirac model This affects results for the RJ 65 and DJ 65 measurements only When Fibre Channel is selected RJ and DJ parameters are extracted according to guidelines given in ANSI INCITS Technical Report TR 35 2004 Methodologies for Jitter and Signal Quality Specification RJ and DJ values are selected that cause an exact match between the bathtub curves from the dual dirac and the full analytical models at two prescribed BER levels When PCI FB DIMM is selected RJ and DJ parameters are determined using the methodology defined in the PCI Express Gen 2 and Fully Buffered DIMM specifications In this technique the bathtub curves are plotted on a Q scale that linearizes the tails of the bathtub and the RJ and DJ values are derived from where the asymptotes to the curves intersect the BER 0 line Waveform Interpolation Type Select the type of interpolation that is used between sample points to determine the exact time when a waveform crosses a reference voltage level Linear interpolation is faster but introduces distortion that raises the jitter noise floor slightly Sin x x Interpolation also known as Sinc Interpolation approaches theoretically perfect waveform reconstruction but is computationally expensive Cancel Discards the changes and closes the window OK Accepts the changes and closes the window Related Topics Preferences General DPOJET Jitte
196. on calculates CC Period measurement using the following equation AP 2p pae 1 Where AP is the difference between adjacent periods P Clock is the clock period measurement 178 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms Positive and Negative CC Duty Positive and Negative CC Duty The CC Duty and CC Duty measurements calculate the difference in positive or negative pulse widths from one cycle to the next The application calculates these measurements using the following equations AW AW AW AW AW AW Where AW is the difference between positive pulse widths of adjacent clock cycles AW is the difference between negative pulse widths of adjacent clock cycles W is the positive pulse width measurement W is the negative pulse width measurement TIE TIE Time Interval Error is the difference in time between an edge in the source waveform and the corresponding edge in a reference clock The reference clock is usually determined by a clock recovery process performed on the source waveform For Explicit Clock clock recovery the process is performed on an explicitly identified source If the Signal Type is Clock The application calculates Clock TIE measurement using the following equation Tig CU as p Gack T Cock Where TIEClock is the clock time interval error T Clock is the VRefMid crossing time for the specified clock edge T Clock js the corresponding edge time fo
197. ons of all measurements and statistical characteristics and an appropriate range of values for each combination The application does not provide any limits file You can create one by specifying limits for any of the result parameters such as Mean Std Dev Max Min peak to peak population MaxPosDelta and MinPosDelta For each of these result parameters you can specify Upper Limit UL Lower Limit LL or Both The measurement names in the limits file must be entered as mentioned in Setting Up the Application for Analysis see page 16 NOTE The limits file supports only absolute values To include Pass Fail status in the result statistics you can create a limits file using an XML editor or any other editor in the following format If the file is created in any other editor such as notepad it should be saved in Unicode format lt xml version 1 0 encoding utf 16 gt lt Main gt lt Measurement gt NAME Per iod NAME STATS STATS NAME Mean c STATS NAME lt LIMIT gt UL lt LIMIT gt lt UL gt 1 lt UL gt lt LL gt 0 lt LL gt lt STATS gt lt STATS gt lt STATS_NAME gt StdDev lt STATS_NAME gt lt LIMIT gt LL lt LIMIT gt lt UL gt 1121 lt UL gt lt LL gt 0121 lt LL gt lt STATS gt lt STATS gt lt STATS_NAME gt Max lt STATS_NAME gt lt LIMIT gt BOTH lt LIMIT gt lt UL gt 1 lt UL gt lt LL gt 0 lt LL gt lt STATS gt lt STATS gt STATS NAME Mi n
198. or such as Notepad or may be imported into spreadsheets such as Excel xml Ascii file containing measurement setup information limits or other data in Extensible Markup Language set Binary file containing oscilloscope setup information in a proprietary format mht An HTML archive file compatible with common Windows applications and contain the full report including text and graphics wfm Binary file containing an oscilloscope waveform record in a recallable proprietary format DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Application Menu Shortcuts Application Menu Shortcuts The DPOJET application provides shortcuts for navigating the user interface Use Alt A for the Analyze menu and AIt A J for Jitter and Eye Analysis Use Alt A P for PCI Express NOTE Alt A J is common for all submenus except the Help menu Table 6 Application shortcuts Menu Items SubMenu Shortcut Wizard One Touch Jitter Alt A J W 0 Serial Data Jitter Guide Alt A J W J Select Alt A J S Configure Alt XA J C Results Alt tA J R Plots Alt AtJ P Reports Alt AtJ O Export Data Snapshot Alt At J E D Measurement Summary Alt tA J E S Data Logging Alt AtJ L Preferences Alt A J F Limits Alt AtJ l Measurement Summary Alt At J M Deskew Alt A J K Help About DPOJET Alt H J Help on Jitter and Eye Analysis Alt H T Returning to the Application 14 When you a
199. or the Strobe channel Sourcel the mid reference level should be set to OV and the High and Low references are not used The reference levels for the Data channel Source2 are mapped to the source configuration panel as follows 192 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms DDR Setup and Hold Measurements Typical values for the reference levels for some current technologies can be found here B DDR2 400 DDR2 533 Reference Levels see page 195 m DDR2 667 DDR2800 Reference Levels see page 195 m DDR3 800 through DDR3 1600 Reference Levels see page 196 DPOJET Jitter and Eye Diagram Analysis Tools 193 ionem E UU DDR Setup Hold Reference Levels Single ended DQS For systems with a single ended DQS signal the waveform reference points for the Setup tDS and Hold tDH measurements details are as shown Das Vigo min e ee een ew n nd www enn ce ee nee eer iR High Rise prs e Bo eee High Fall Vreg 7 S lt lt ss sSS lt 6s 45 lt s 5 S Vide max pee LAAdLT RL Bo T I Low Rise Vigg max wen cern ern sf pense ececce Low Fall t t DDR DPOJET Ref Level 4 4 Ref Level Designations DS tDH DS tDH D es ignations VHag min 2 A 2 4 p L High Rise Viigig min 4 T m High F
200. ord Length so that there are more than 100 edges in the acquisition Launch the DPOJET application Click Analyze gt Jitter And Eye Analysis gt Deskew Set the Reference channel source to Chl The source waveform is the reference point used to deskew the remaining channels Set the Channel to be Deskewed source as Ch2 To start the process click Perform Deskew Repeat steps 7 and 8 for other Ch waveforms 10 Select Summary see page 36 to view the deskew values DPOJET Jitter and Eye Diagram Analysis Tools 35 Operating Basics Deskew Summary Deskew Summary The Deskew Summary dialog lists the channel source and its deskew values 36 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Export Data Snapshot Statistics Export Data Snapshot Statistics You can save a snapshot of the current statistics in csv format The default location is C NTekApplicationsNDPOJETNLogsNStatistics Click Analyze gt Jitter and Eye Analysis gt Export gt Data Snapshot gt Statistics to view the following Data Snapshot Statistics Measurement C Tek Applications DPOJET Logs Statistics 070903_124158 Browss Table 14 Data Snapshot Statistics options Item Description Select Target Measurements Displays the measurement list Click a row to select the measurement By default all measurements are selected Select All Selects all the measurements in the list for
201. other jitter measurements as a convenience This convenience function is not supported via the programmable interface DPOJET Jitter and Eye Diagram Analysis Tools Algorithms TJ BER TJ BER DJ Total Jitter at a specified Bit Error Rate BER This extrapolated value predicts a peak to peak Jitter that will only be exceeded with a probability equal to the BER It is generally not equal to the total jitter actually observed in any given acquisition A single TJ BER value is determined for each acquisition by means of RJ DJ separation analysis Related Topics m Jitter Analysis Through RJDJ Separation m Estimation of TJBER and Eye WidthBER Deterministic Jitter DJ is the peak to peak amplitude for all timing errors that follow deterministic behavior A single DJ value is determined for each acquisition by means of RJ DJ separation analysis Related Topics m Jitter Analysis Through RJDJ Separation Dual Dirac Deterministic Jitter Dual Dirac Deterministic Jitter DJ 65 the peak to peak magnitude for all timing errors exhibiting deterministic behavior calculated based on a simplifying assumption that the histogram of all deterministic jitter can modeled as a pair of equal magnitude dirac functions impulses A single DJ 66 value is determined for each acquisition by means of RJ DJseparation analysis Related Topics m Jitter Analysis Through RJDJ Separation m Jitter Estimation Using Dual Dirac Models Phase Noise The Phas
202. ow Size Measurement analysis is done on a window of size 200 cycles with a step increment of 1 cycle As per the standard the default window size is 200 You can set window size up to 1M Sequencing Use the Control Panel see page 61 to start or stop the sequence of processes the application and oscilloscope use to acquire information from a waveform The application then determines if the algorithm for the selected measurement can be applied to the waveform information Sequencing is the steps to acquire waveform information determine if the information is usable for the measurement take the measurement and display the results and plots if selected When you click Recalc Single or Run the corresponding button is changed to Stop and the Progress indicator is displayed For more details refer to the Control Panel see page 61 Eye Diagram The Progress Indicator displays the sequencer state Select Stop if you want to interrupt the sequence before its completion For more details on progress bar status messages refer to Progress Bar Status Messages see page 169 DPOJET Jitter and Eye Diagram Analysis Tools 119 Operating Basics Viewing Statistical Results Viewing Statistical Results 120 There are two ways to view the statistical results of measurements Summary Details The application displays results for the measurements for all acquisitions or for the current acquisition By defa
203. pes Click Next to select the measurement sources Serial Data Jitter Wizarc Repeating Pattern eae 2UI Related Topics RJ DJ Analysis Parameters m RJ DJ 28 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Select Sources Select Sources In this step you can select the measurement source s The source selection depends on the measurement type By default Sourcel is displayed automatically for all the measurements depending on the waveform last used If Ch1 Refl Mathl is displayed for Sourcel Source2 is Ch2 Ref2 Math2 else Ch1 Math1 Refl will be selected as Source2 Serial Data Jitter Wizarc The Source2 option is displayed only for two source measurements such as Skew DPOJET Jitter and Eye Diagram Analysis Tools 29 Serial Data Jitter Wizare Click Next to configure autoset Configure Autoset Options In this step you can choose to automatically adjust the oscilloscope settings or the reference levels before the measurement The default of Yes is recommended By selecting No you will retain the current oscilloscope settings and or ref levels Click Next to select plots 30 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics _ Select Plots Serial Data Jitter Wizare Would you like the horizontal and vertical settings optimized based on the signal Yes Recommended O No please retain the current setting
204. ple 108 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics RJ DJ Analysis of Arbitrary Pattern in a band limited link where a string of ones follows a string of zeros the signal may require three or four bit periods to fully settle to the high state In this method an analysis window with a width of K bits is slid along the waveform For each position of the window the time interval error of the rightmost bit in the window is stored along with the K 1 bit pattern that preceded it After the window has been slid across all positions it is possible to calculate the component of the jitter that is correlated with each observed K 1 bit pattern by averaging together all the Observed errors associated with that specific pattern In the configuration menu for the arbitrary pattern method the Window Length field allows you to select how many bits are included in the sliding window The window should include enough bits to encompass the impulse response of the system under test usually 5 to 10 bits A good practical test is to check whether increasing the window length causes any appreciable change in the jitter results if not the window length is effectively capturing all the ISI effects The disadvantage of increasing the window length is that it uses more memory and requires additional processing time The configuration menu also includes a field for selecting what population of each K 1 bit pattern must be accumulated before
205. plicit clock where the clock and data signals are in phase OK Accepts the changes and closes the window Related Topics m Effect of Nominal Clock Offset on Eye Diagrams NOTE If there is unwanted skew between the data and explicit clock signals the channels must be properly deskewed Refer to your oscilloscope online help on how to deskew the channels Configuring an Eye Diagram for Mask Hits An eye diagram plot is activated whenever a mask hits measurement is selected Click Configure in the plots panel to configure the plot DPOJET Jitter and Eye Diagram Analysis Tools 137 Operating Basics 138 Item Configuring an Eye Diagram for Mask Hits Description Mask Horizontal Scale Shows which mask has been selected For the Mask Hits measurement the mask selection is performed as part of measurement configuration rather than plot configuration Auto Scale Resolution When checked causes the horizontal scale to be adjusted automatically Manually sets the horizontal resolution when Auto Scale is unchecked Superimpose Reference Clock Eye if available When checked superimposes DQS eye onto the data eye diagram Ref Clock Alignment Determines how an eye diagram is positioned on the plot The position is determined by the eye reference point which is the location of overlapping recovered or explicit clock edge locations Typically the eye is located so that wavefo
206. pplication Recall the tutorial waveform NOTE The screen captures shown in this section are from a DPO7254 oscilloscope Setting Up the Oscilloscope The steps to set up the oscilloscope are 1 Click File gt Recall Default Setup in the oscilloscope menu bar to recall the default settings 2 Press the individual CH1 CH2 CH3 and CH4 buttons as needed to add or remove active waveforms from the display Starting the Application Click Analyze gt Jitter and Eye Analysis gt Select to open the application Waveform Files The application provides the following tutorial waveforms m Rt EyeTutorial wfm B ckminus 50gs 18g 20m patl wfm ckplus 50gs 18g 20m patl wfm B dplus 50gs 18g 20m patl wfm m dminus 50gs 18g 20m patl wfm The waveform files are found at C NTekApplicationsNDPOJETNExamples DPOJET Jitter and Eye Diagram Analysis Tools 147 Tutorial Recalling a Waveform File Recalling a Waveform File To recall a waveform file follow these steps 1 Click File gt Recall in the oscilloscope menu bar to display the Recall dialog box NOTE If the application is in button mode select the Recall button to recall the tutorial waveform Click Waveform icon in the left of the Recall dialog box Select Refl Ref2 Ref3 or Ref4 as the Destination option Browse to select the waveform Use the keypad to edit the waveform file name Click Recall The oscilloscope recalls and activates th
207. pulation The Population control allows you to limit the amount of waveform data that is analyzed This is often done in industry standards to make sure that there is consistency between measurement techniques 84 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 42 Global Population options Configuring Population Limit Item Description Off Disables the application from using a Population limit while taking measurements On Enables the application to use a Population limit while taking measurements Configure Displays the Population Limit see page 85 dialog box wherein you can set a limit on a maximum population to obtain for selected measurements Configuring Population Limit Table 43 Population Configure options Item Description Limit By Population The limit determines the population of measurement observations that will be accumulated Some measurements may accumulate observations more quickly than others DPOJET Jitter and Eye Diagram Analysis Tools 85 Operating Basics Table 43 Population Configure options cont Item Acquisitions General Description The limit determines the number of acquisition cycles that will be performed Stop Conditions Each Measurement Each measurement stops accumulating as soon as it reaches the specified limit Sequencing does not stop until all measurements have reached the limit
208. r and Eye Diagram Analysis Tools Operating Basics Preferences Path Defaults Preferences Path Defaults Preferences Path Defaults Click Analyze gt Jitter and Eye Analysis gt Preferences gt Path Defaults to view the following pee Default image export directory i CAT ekpplcation DPOJET mages Browse Measu emen Default logging export directory Path Defaults C TekAppkcations DPOQIETWLog Browse Default report output directory The Path Defaults allows you to set the path for images reports and log files Click Browse to modify the default directory path Table 24 Preferences Path Defaults options Item Description Default image export directory Selects the directory to which images will be saved unless overridden at the time of the export Default logging export directory Selects the directory to which logs will be saved unless overridden at the time of the export Default report export directory Selects the directory to which reports will be saved unless overridden at the time of the export Cancel Discards the changes and closes the window OK Accepts the changes and closes the window Related Topics Preferences General Preferences Measurement DPOJET Jitter and Eye Diagram Analysis Tools 55 Operating Basics Limits Limits 56 Limits file allows you to determine Pass or Fail status for tests Each serial data application provides limits file that includes combinati
209. r the specified reference clock If the Signal Type is Data The application calculates Data TIE measurement using the following equation DPOJET Jitter and Eye Diagram Analysis Tools 179 Algorithms RJ RJ DM NA qu Where TIED ta is the data time interval error T Pata js the VRefMid crossing time in either direction T Pata is the corresponding edge time for the specified reference clock The subscript k is used to indicate that there is one measurement per Unit Interval rather than one measurement per actual edge Random Jitter RJ 1s the rms magnitude of all timing errors not exhibiting deterministic behavior A single RJ value is determined for each acquisition by means of RJ DJ separation analysis Related Topics E Jitter Analysis Through RJDJ Separation Dual Dirac Random Jitter Dual Dirac Random Jitter RJ 68 is the rms magnitude of all timing errors not exhibiting deterministic behavior calculated based on a simplifying assumption that the histogram of all deterministic jitter can modeled as a pair of equal magnitude dirac functions impulses A single RJ 66 value is determined for each acquisition by means of RJ DJ separation analysis Related Topics amp Jitter Analysis Through RJDJ Separation E Jitter Estimation Using Dual Dirac Models Jitter Summary 180 The Jitter Summary is not a single measurement The Jitter Summary button on the graphical user interface simply creates one each of all the
210. re than one session to complete the tutorial lessons you can stop the tutorial and return to it later To save the application setup refer to Saving a Setup File see page 15 To exit the DPOJET application click present at the right corner of the application Returning to the Tutorial To return to the tutorial setup you can start the application and then recall the saved setup To recall the application setup refer to Recalling a Saved Setup File see page 15 154 DPOJET Jitter and Eye Diagram Analysis Tools Parameters About Parameters About Parameters This section describes the DPOJET application parameters and includes the menu default settings Refer to the user manual for your oscilloscope for operating details of other controls such as front panel buttons The parameter tables list the selections or range of values available for each option the incremental unit of numeric values and the default selection or value Refer to the GPIB see page 211 section for a complete list of the GPIB Command Syntax The topics include a complete list of the GPIB commands along with the arguments variables and variable values that correspond to the DPOJET parameters Measurement Select Parameters The Measurement Select includes the following measurement categories m Period Freq Frequency Period CC Period N Period Pos Width Neg Width Duty Cycle Duty Cycle CC Duty and CC Duty B Jitter TIE RJ DJ
211. rementName Source s Min source Number gt wfm format Click Close to close the dialog box Period1 Ch1 Min1 wfm Pos Width1 Ch1 Max1 wfm Pos Width1 Ch1 Min1 wfm Neg Width1 Ch1 Max1 wfm Neg Width1 Ch1 Min1 wfm DPOJET Jitter and Eye Diagram Analysis Tools 4T Operating Basics Measurement Configuration Summary Measurement Related Topics Data Logging Statistics Data Logging Measurement Measurement Configuration Summary Measurement Click Analyze gt Jitter and Eye Analysis gt Measurement Configuration Summary gt Measurement to view measurement source and the configuration parameters of each measurement Measurement c po z Edges gt Signal Type Auto Clock Edge Rise Filters gt F1 Spec No Filter F2 Spec No Filter General gt Measurement Range Limits Off Max ims Min 0s Custom Name Filters gt F1 Spec No Filter F2 Spec No Filter General Measurement Range Limits Off Max 10ns Min 1ns Custom Name Filters gt F1 Spec No Filter F2 Spec No Filter General gt Measurement Range Limits Off Max Ref Levels 10ns Min ins Custom Name Edges gt Signal Type Auto Clock Edge Rise Filters gt F1 Spec No Filter F2 Spec No Filter General gt Measurement Range Limits Off Max 10GHz Min 1MHz Custom Name Edges gt Signal Type Auto Clock Edge Rise General gt Measurement Range Limits Off Max 1ms M
212. ret iara 30 DelectPlOts isa CERE 31 Jitter And Eye Analysis About Jitter And Eye Diagram Analysis Options ccccee cence ence eee e ence meme 33 Dj ITEM 34 Deskew Summary sereine a e M Rare eue eee Ree a ue E deb ese age ER 36 Export Data Snapshot Statistics se anie cece ee eme messe emere nnns 37 Export Data Snapshot Measurement 0 ccc cece cece cece eee nent eee e messe e esr een 38 Export Measurement Summary 0 ccc ce cece ence cent een ehe e she ee e ese eene 40 Data Logging Data Logging Statisties es cete eese ES pre aea pret BE ees waned sey caw ESTE Pee E 41 Data Logging Measurement 00 cece cee cece eee ene eese ehe eese ese ehe eser 43 Data Logging Worst Ca8ecccsxciesice ee e ER ed re nace rA tioned PATRE On E TED nada deine 46 Measurement Summary Measurement Configuration Summary Measurement csse 48 Measurement Summary Ref Levels esses eme eee eese 49 Measurement Summary Misc sssssssssssssssssesssessee ese eese e eser ese nenas 50 Preferences Setup About Preferences Setup lt s uc000 000 docks etre or ea rne Hawn e EET E Meu nde reruns 5 Preferences General samenen itte veste a a a tut tn ne eee a i eddie turtus 5 Preferences Measurement ssssssssssssssssessssse ee e me se he he he se hee e enne 53 Preferences Path Defaults execs eerte eec e RR a Oe erences deepen e eee des 55 ern UNUM HE 56 Taking Measurements About Taking a New Measureme
213. rm edges are approximately at 25 and 75 of the width of the diagram This ensures that the eye opening is centered on the plot facilitating cursor measurements and mask testing Auto Determines the alignment property automatically Eye diagram is aligned automatically Auto is typically equivalent to Left Center Eye reference point is centered on the plot Center alignment is appropriate for DDR Write bursts or other signals with explicit reference clock where the clock and data signals are out of phase Left Eye reference point is positioned on the left of the plot so that eye opening is centered Left alignment is appropriate for DDR Read bursts and signals with recovered clock or explicit clock where the clock and data signals are in phase OK Accepts the changes and closes the window DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics About Viewing Plots Related Topics m Effect of Nominal Clock Offset on Eye Diagrams NOTE If there is unwanted skew between the data and explicit clock signals the channels must be properly deskewed Refer to your oscilloscope online help on how to deskew the channels About Viewing Plots You can create and configure up to four plots If you already have measurement results creating a plot will cause it to be displayed immediately If there are no current results the plot will be created when you sequence the application and results have been calcu
214. rm plot allows them to be seen in the context ofa continuous time waveform Eye Diagram Plot Usage An eye diagram is a plot of the voltage versus time for a serial bit stream with the time axis wrapped so that all unit intervals are superimposed on top of each other in a time aligned fashion Because the resulting plot has many waveforms overlaid color grading is used to separate areas with many coincident waveforms from areas that are only rarely crossed If there is an area free of waveforms in the center of the diagram the eye is said to be open and a comparator circuit repetitively sampling the waveform at this point in the unit interval could unambiguously separate the two logic states For experienced signal integrity engineers the eye diagram allows many common problems to be recognized instantly Selecting Plots Before or after you take measurements you can set up plots for the selected measurements by following these steps 1 Click Plots in the navigation panel see page 60 to view the Select Plot window The currently active measurements and source s are displayed in the table on the left measurement table 2 Click any of the plot icons that are available for the selected measurement The corresponding plot type and measurement are then added to a table on the right plot table 3 Add another plot for the current measurement or select a different measurement and choose from its plot types A max
215. rowser where you specify the directory to save the generated report You can also edit the report name in the Save As browser The generated report is saved in C NTekApplicationsNDPOJETNReports 144 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics About Reports Reports Format The generated reports are in mht format and includes the following configured set of information Setup Configuration such as DPOJET version oscilloscope version and the Pass Fail status Measurement Configuration such as measurement name source and other configuration parameters Source Reference Levels displays the reference voltage levels for the high mid and low thresholds for the rising edge and for the falling edge of all sources and the hysteresis m Miscellaneous Settings such as Gating Qualify and Population status B Pass Fail Summary indicating the Pass Fail status for the selected measurements Measurement Results with statistics m Plot Images includes both selected plots and oscilloscope waveforms DPOJET Jitter and Eye Diagram Analysis Tools 145 Operating Basics About Reports 146 DPOJET Jitter and Eye Diagram Analysis Tools Tutorial Introduction to the Tutorial Introduction to the Tutorial This tutorial teaches how to set up the application take measurements and view results as plots or statistics Before you begin the tutorial perform the following tasks m Setup the oscilloscope B Start the a
216. rtant but optional Your name Your company Your mailing address m Your phone number B Your FAX number Enter your suggestion Please be as specific as possible Please indicate if you would like to be contacted by Tektronix regarding your suggestion or comments To include screen shots of the oscilloscope waveform and DPOJET user interface from your oscilloscope menu bar click File gt Save As gt Screen Capture To include screenshots of the DPOJET plots select the floppy disk icon from the plots toolbar In either case enter a file name in the Save As dialog box select an image file format For Example bmp or png or jpeg choose a save location and select Save You can then attach the file s to your e mail depending on the capabilities of your e mail editor 4 DPOJET Jitter and Eye Diagram Analysis Tools Getting Started Product Description Product Description DPOJET is a jitter timing and eye diagram analysis tool for Tektronix Performance Digital Oscilloscopes DPO7000 and DSA DPO70000 series DPOJET enables you to achieve new levels of productivity efficiency and measurement reliability on complex clock digital and serial data signals The application provides the following features One Touch Jitter Summary Measurement Setup Wizard Auto detection of signal type clock or data RJ DJ decomposition on repeating and arbitrary data patterns Spectral plot with peak Hold Averaging and Nomina
217. ry 100 Explicit Clock Edge 101 Explicit Clock PLL 102 Export Data Snapshot Measurement 38 Export Data Snapshot Statistics 37 Export Figure 140 Export Measurement Summary 40 Export Results to Ref 123 Exporting Plot Files 142 Eye Analysis 5 Eye Diagram 126 Eye Diagram for Mask Hits 137 Eye Diagram Plot for Eye Height 136 Eye Diagram Plot Parameters 166 Eye Height 186 Eye Summary 31 Eye Width 186 F Fall Time 18 File Name Extensions 13 Filter Spec 89 Filters 87 Filters Parameters 164 Five Time Free Trial 1 Flier Spec 89 Freq F1 89 Freq F2 89 Frequency 16 From Edge 112 G Gating 81 General 86 General Parameters 164 Global 81 Global Parameters 164 GPIB Program 211 GPIB Reference Materials 211 H Height 19 High 188 High Pass 89 High Pass filter 87 High Time 18 High Low 190 Histogram 126 Histogram Plot Parameters 166 Hold 18 Horizontal cursors 142 Horizontal Resolution 68 Horizontal Scale 132 Hysteresis 50 image export directory 55 Installing the Application 8 J Jitter Analysis 5 Jitter Analysis Through RJ DJ Separation 205 Jitter Estimation Using Dual Dirac 207 Jitter Summary 180 K Known Data Pattern 97 L Limit 86 DPOJET Jitter and Eye Diagram Analysis Tools Limit By Population Acquisitions 85 Limits 56 Limits files 13 Log Future Statistics 42 Log Notifiers 60 Log Worst Case Waveforms
218. s 0 0ccc cece cece nee ee eee nee eee eene 106 Bit Config for PCI Express Measurements 0 cccecce cece ence eee ee eee 107 RJDJ Ludum 107 RJ DJ Analysis of Repeating Pattern 0 cece cece eee nce e ee eee emen 108 RJ DJ Analysis of Arbitrary Pattern 2 0 2 0 0 c cece cee ee eee e eect ee ee eme mee 108 DPOJET Jitter and Eye Diagram Analysis Tools ii Table of Contents Edges Configuring Edges ccc cece ence enn EEE EEE EEE EE EEE EES 110 Configuring Edges for Skew Measurements ccccece cece eens eee 112 Configuring Edges for Differential CrossOver Voltage Measurements 112 Configuring Edges for Phase Noise Measurements esceeeeeeeee eee eeeneeeees 113 Configuring Edges for N Period Measurements cccceee cence eee eeaeeeeeenaeenes 114 Configuring Edges for Two Source Measurement 0 cccceece cece eee eeeeenaeenes 115 Configuring Edges for CC Period Duty Cycle Measurements 0c eeeeee eens 115 Configuring Edges for DCD Measurement cc cece cece eee e ne eene 116 Configuring Edges for DDR tCH avg and DDR tCL avg ccc cece cece ee ee neces 116 Configuring Edges for DDR tERR m n 6 e ccc cence cece een eee emere 117 Configuring Edges for DDR tERR D c ccc cece cee nee nee I eee 118 Configuring Edges for DDRtJIT per DDRtCK avg and DDRtJIT duty
219. s NOTE When taking measurements in the Run mode you must stop the sequencing before you can use some plot features Jitter and Eye Diagram Analysis Tools DPOJET Jitter and Eye Diagram Analysis Tools 125 Operating Basics Plot Usage Table 61 Plot type definitions Item Description Time Trend Represents the measurement values versus the time location Data Array Represents the measurement values versus the index number of the measurement array Histogram 1 Represents measurements sorted by value as a distribution of measurement values versus the number of times the value occurred Spectrum Represents the frequency content computed using the FFT of the Time Trend of the measurement data Transfer Represents the magnitude ratio of spectrum of time trend data of two measurements from the following set Clock Period Clock Frequency Clock TIE Clock PLL TIE Data Period Data Frequency Data TIE Data PLL TIE Phase Noise 2 Represents the phase noise of a clock signal and is plotted in the frequency domain for only Clock TIE measurements Eye Diagram 3 Represents data for the eye diagram based on the recovered clock as the timing reference used for mask testing Waveform 4 Represents the acquired waveform It is available for use with eye diagram mask tests to locate bit errors in the real time waveform Bathtub 5 Represents the Bit Error Rate versus the unit interval for measurements that includ
220. s Would you like the reference levels 4 Configure Autoset Options automatically chosen based on the signal 7 Yes Recommended s No please retain the current ref levels Select Plots In this step you can select the plots that you want to display The measurements that you selected earlier also determine which plot types will be available in this step The following table lists the available plots for measurements Table 13 Measurements and available plots Measurement Plots Period and Frequency Period Trend Period Spectrum Period Histogram Skew Skew Trend Skew Spectrum TIE TIE Trend TIE Spectrum TIE Histogram Jitter Summary TIE Trend TIE Spectrum TIE Histogram and Bathtub Curve Eye Summary Eye Diagram Transition Bit Eye Diagram Non Transition Bit Unit Interval Histogram and Eye Width BER In this example the selections shown are for a Period and Frequency measurement DPOJET Jitter and Eye Diagram Analysis Tools 31 _ Select Plots Serial Data Jitter Wizare What plots would you like to see Z Time Trend Period Click Finish to start the acquisition sequence using the selected settings The Serial Data Jitter Guide window closes and the results screen is displayed 32 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics About Jitter And Eye Diagram Analysis Options DPOJET Plots sm ph ESET BESET Sc Period Histogram T TM 47 95ns i
221. s detail Zoom in Horizontal only Expands the horizontal axis only and retains the vertical axis m 1e iD Resets the zoom to 10096 Changing the Scale of Data in a Plot Zoom To change the scale of the data in a Plot Details window select one of the following plot zoom tools a amp zooms in to expand the scale zooms out to contract the scale a Q zooms in to expand the horizontal axis only 3 a moves the plot anywhere within the scale B 5 zooms in to restore the entire waveform data When you select the A tool you can use a select drag release action to expand part of the waveform zoom in by an arbitrary amount on both axes After you select touch with a finger or click with the mouse and begin dragging a bounding box shows what part of the waveform will be expanded upon release Select any part of the plot to expand the data by a factor of two 2X equally on both axes Double selecting expands the data to the maximum factor To contract an expanded part of the data zoom out select anywhere on the data The view contracts to the values that existed before the most recent expansion of the data Selecting multiple times will restore successively earlier views To expand the scale of the horizontal axis only by a factor of two 2X click a part of the waveform The plot retains the scale of the vertical axis TIP Select 5 to see the entire available waveform Using Cursors in a Plot
222. s fully high or fully low DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Ref Levels Low Rising Versus Falling Thresholds You can specify thresholds for each of the reference voltage levels High Mid and Low The application uses the thresholds to determine the following events B A Low Mid High rising event which occurs when the waveform passes through the corresponding Rise threshold in the positive direction B ALow Mid High falling event which occurs when the waveform passes through the corresponding Fall threshold in the negative direction For a given logical reference level such as Low Mid or High rising and falling events alternate as time progresses NOTE In many cases the rising and falling thresholds for a given reference voltage level are set to the same value In those cases a hysteresis value helps prevent spurious edges produced by small amounts of noise in a waveform Using the Hysteresis Option The hysteresis option can prevent small amounts of noise in a waveform from producing multiple threshold crossings You can use a hysteresis when the rising and falling thresholds for a given reference voltage level are set to the same value The reference voltage level the hysteresis value defines a voltage range that must be fully crossed by the waveform for an edge event to occur If the decision threshold is crossed more than once before the waveform exits the hysteresis band the m
223. s or queries the clock bit rate Used if DATARate is 1 Syntax DPOJET MEAS x ENVIronment CLOCKRecovery CLOCKBitrate Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt CLOCKRecovery CLOCKFrequency Sets or queries the clock frequency Used with Constant Clock Fixed clock recovery method Syntax DPOJET MEAS x ENVIronment CLOCKRecovery CLOCKFrequency Inputs NR3 Outputs NR3 DPOJET MEAS x CLOCKRecovery PATTern Turns on or off the usage of CLOCKPath to specific a known data pattern Syntax DPOJET MEAS x CLOCKRecovery PATTern 226 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt CLOCKRecovery CLOCK Path Inputs 1 0 Outputs 1 0 DPOJET MEAS lt x gt CLOCKRecovery CLOCKPath Sets or queries the current known clock pattern path Syntax DPOJET MEAS lt x gt ENVIronment CLOCKRecovery CLOCKPath Inputs String Outputs String DPOJET MEAS lt x gt CLOCKRecovery MEANAUTOCalculate Sets or queries how often the clock is calculated either FIRST or on EVERY acquisition Syntax DPOJET MEAS lt x gt CLOCKRecovery MEANAUTOCal culate Inputs FIRST EVERY Outputs FIRST EVERY DPOJET Jitter and Eye Diagram Analysis Tools 227 GPIB Commands DPOJET MEAS lt x gt CLOCKRecovery NOMINALOFFset DPOJET MEAS lt x gt CLOCKRecovery NOMINALOFFset Sets or queries the clock offset Syntax DPOJET MEAS x CLOCKRecovery
224. sis Tools GPIB Commands DPOJET MEAS lt x gt RESULts ALLAcqs MAX DPOJET MEAS lt x gt RESULts ALLAcqs MAX Returns the maximum value for all accumulated measurement acquisitions for slot lt x gt Syntax DPOJET MEAS lt x gt RESULtS ALLACqs MAX Outputs NR3 DPOJET MEAS lt x gt RESULts ALLAcqs MIN Returns the minimum value for all accumulated measurement acquisitions for slot lt x gt Syntax DPOJET MEAS lt x gt RESULtS ALLAcqs MIN Outputs lt NR3 gt DPOJET MEAS lt x gt RESULts ALLAcqs PK2PK Returns the peak to peak value for all accumulated measurement acquisitions for slot lt x gt Syntax DPOJET MEAS lt x gt RESULtS ALLAcQs PK2PK Outputs lt NR3 gt DPOJET Jitter and Eye Diagram Analysis Tools 253 GPIB Commands DPOJET MEAS lt x gt RESULts ALLAcqs MAXCC DPOJET MEAS lt x gt RESULts ALLAcgs MAXCC Returns the maximum positive cycle to cycle delta of the selected measurement Syntax DPOJET MEAS x RESULtS ALLACQS MAXCC Outputs NR3 DPOJET MEAS lt x gt RESULts ALLAcqs MINCC Returns the maximum negative cycle to cycle delta of the selected measurement Syntax DPOJET MEAS X RESULtS ALLACqs MINCC Outputs NR3 DPOJET MEAS x RESULts ALLAcqs SEG x MINHits 254 Returns the minimum mask hits measurement for the given segment either SEGI SEG2 or SEG3 Syntax DPOJET MEAS x RESULtS ALLACQsS SEG x MINHits
225. sponding DPOJET xml file in the same directory will be recalled as well if DPOJET has been launched at least once since the oscilloscope application was started If DPOJET has not been launched at least once the oscilloscope settings will be recalled but the DPOJET configuration will be ignored Recalling the Default Setup To recall the default application and oscilloscope settings click File gt Recall Default Setup DPOJET Jitter and Eye Diagram Analysis Tools 15 Operating Basics Setting Up the Application for Analysis Setting Up the Application for Analysis Refer to the following sections for more details on various measurements B Period and Frequency measurements B Jitter measurements m Time measurements m Eye measurements Amplitude measurements Standard Measurements Table of Measurements Period Freq 16 Definitions of the period and frequency related measurements are given in the following table Table 7 Period Frequency measurements definitions Measurement Description Period For clock signals the elapsed time between consecutive crossings of the mid reference voltage level in the direction specified one measurement is recorded per crossing pair For data signals the elapsed time between consecutive crossings of the mid reference voltage in opposite directions divided by the estimated number of unit intervals for that pair of crossings one measurement is recorded per unit interval so N
226. st for saving statistics Clear All Deselects all the measurements from the list Save Measurements Save Saves the data points for current acquisition of selected target measurements in a log file Folder Browse Saves the csv file in the specified directory The default directory is C TekApp1ications DPO JET Logs Measurements File Names View Displays View Log File Names see page 44 dialog box which lists the measurements and their source s with corresponding log file name inYYMMDD HHMMSS Measurement Name SourceName csv format Close Accepts the changes and closes the window View Log File Names The View Log File Names dialog box lists the measurements and their source s with corresponding log file name in YYMMDD HHMMSS Measurement Name SourceName csv format Click Close to close the dialog box DPOJET Jitter and Eye Diagram Analysis Tools 39 Operating Basics Export Measurement Summary IPFE 070903 130245 Period1 Ch1 csv 070903 130245 Pos Width1 Ch1 csv 070903 130245 Neg Width1 Ch1 csv Related Topics B Export Data Snapshot Export Measurement Summary Click Analyze gt Jitter and Eye Analysis gt Export gt Measurement Summary to save the generated report in C NTekApplicationsNDPOJETNReports The exported measurement summary contains information only about application setup and configuration 40 DPOJET Jitter and Eye Diagram Analys
227. t Figure e Print Figure amp A E W ip sie Zoom and Pan NM wal ld Vertical and Horizontal Cursor controls 1 zz rh o Moving and Resizing Plots pa Plot properties Fri Plot Summary Views aj ay Gj aj Full view of plots 1 to 4 Moving and Resizing plots You can move and resize plot windows the same way you would move and resize any window You can change the plot size to the whole display of the oscilloscope or to half the display When viewing a plot in half the display you can position the plot to the top or bottom The tools also return the plot to the original size To position a plot quickly on the oscilloscope select one of the following tools in the plot window a 1 enlarges the plot to fill the entire display m 7 positions the plot to the top B positions the plot to the bottom m 4 always keep the plot on top layer Using Zoom in a Plot Once you have created a plot you can use the Zoom tools to examine the data at various scales TIP If you prefer to use the zoom functions in a plot window with your finger you can activate the Touch Screen on the oscilloscope 140 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Using Cursors in a Plot Table 64 Zoom functions in a plot Item Description amp Zoom in Horizontal and Vertical Expands part of the plot the data appears in more detail Zoom out Contracts part of the plot the data appears in les
228. t sequence is obtained This is because PJ and RJ are not correlated to a particular data sequence and thus are averaged out If each bit is assumed to be affected by N preceding bits there are a total of 2N possible data sequences The sequence length N is a configurable parameter To get statistically sound average values for the data dependent jitter a minimum population of observations is required for each individual pattern that occurs at least once This population limit is also configurable by the user By the above means the data dependent jitter is characterized Once characterized the data dependent jitter on a bit by bit basis may be removed from the original jitter versus time record The remaining jitter is composed of periodic and random jitter This jitter is transformed into the frequency domain and the spectral analysis approach is used to separate the impulsive periodic jitter from the broad noise floor of random jitter Estimation of TJ BER and Eye Width BER One of the outcomes of the RJ DJ separation was a mathematical model for random jitter s probability density function PDF and measured values for the PDFs of the deterministic jitter components Since all of these components are assumed to be statistically independent the PDF of the total jitter can be calculated by convolution Integration of the PDF yields the cumulative distribution function CDF which can then be used to create the bit error rate curve batht
229. t x gt LOGging WORSTcase SELect eeeseessseesssssseesee een 233 ID POVE Ts GAT IN Grrr r E E 233 DPOJET QUALify DPOJET OUALIty S FATE 7 re RR RETE Mr ERU ad S ARREUUO CO REST E O ERE REA 234 DPOJET POPUEATION STATE 555 9 EE Tet eese Se Ere NS eee a REP pee P TENES 235 DPOJET EIMITBRISG reto n FRU Eee t E die AA PG e VER EA 237 DPOJET DIRacmodel z 3 iter ere ERI atte P EIEEE 237 puel gd m PL LE M 237 DPOJET SOURCEAUtOSGLU EE E ERG RU es 238 DPOJET REEEevels AU TOSet esser rtr e rris AIT I tess ET 238 DPOJET REFLevels CH lt x gt AUTOSet 2 0 0 cece ee nee ence nnn ee e sese sensns 239 DPOJET REFLevels CH lt x gt ABsolute 0 0 0 c ccc ccc cece enn EE esee esee e ee n enne 240 DPOJET REELevels CHX PER CEN noresi trt ROG Ve ER oe pages 243 DPOJET REFLevel CH lt x gt MIDZer0 n n ccc ccc ccc ene enn enn eI meme eene e eene nee 246 DPOJET MEAS lt x gt RESULIS 21 5 ES B E 246 DPOJET MEAS lt x gt RESULTS STATUS n er aE E EE meme e eese enne 257 Plots DPOJET ADDPlIot se E E VE e E e EIS Ue S Rd 257 DPOJET CEEARADLDEPIOtS eren ra oer REUS eek ote Er NRA eR ee 257 DPOJET PEOTEx DYP67 eiecit etae a e prete te deu se E a UD NUTS 258 DPOJET PLOT zx SOUtC6 ii ds erret aa IET ERN I saga aa AR ERARA AAI REECE 258 DPOJET BEOT x IREND TYPBe eer ero Selene T niet pnb cen OC HE HP en en a 258 DPOJET PLOT lt x gt HISTOgram AUTOsSet 00 0 Ie me eee 259 DPOJET PLOT lt x gt SPEC
230. tage level Setup Elapsed time between the designated edge of a data waveform and that of a clock waveform based on their respective mid reference level crossings Hold Elapsed time between the designated edge of a clock waveform and that of a data waveform based on their respective mid reference level crossings Skew Time difference between two similar edges on two waveforms assuming that every edge in one waveform has a corresponding edge either the same or opposite polarity in the other waveform edge locations are determined by the mid reference voltage level 18 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table of Measurements Eye Table of Measurements Eye Definitions of the eye related measurements are given in the following table Table 10 Eye measurements definitions Measurement Description Height The measured clear vertical eye opening at the center of the unit interval Height High min Low max Width Measured clear horizontal eye opening at the middle reference level Width Ul mean TIE max TIE min Width BER The horizontal eye opening projected to correspond to a specified Bit Error Rate This number is obtained by measuring the jitter on the waveform performing RJ DJ separation analysis creating a bathtub curve and reporting the bathtub width at the appropriate error rate This eye width may not match the observed eye width because it is
231. tarted the application To view the DPOJET application select Analyze gt Jitter and Eye Analysis gt Select Go to Select in the left navigation panel Click Period in the Measurements area The application shows the measurement and source selection on the right of the display The current measurement selection is displayed as Period1 The subsequent selections will be Period2 Period3 and so on In this example Rt EyeTutorial wfm is recalled as Refl and is selected as source for Periodl New measurements initially use the same source as the earlier measurement or the most recently used source Jitter and Eye Diagram Analysis Tools Measurements Period Freq i Pos Width Neg Width N Period DutyCycle Duty Cycle CC Period CC Duty CC Duty Ampl Standard Click or the row which lists the selected measurement to configure the source Select Refl for Periodl For more details refer to Source Setup see page 63 Click Ref Levels Setup The Configure Reflevel menu appears For more details refer to Ref Levels see page 70 Click Configure in the left navigation panel of the main application window to view the configure tabs For more details refer to About Configuring a Measurement see page 76 Click Plots to view the available plots for the selected measurement Select Time Trend for Period For more details refer to Configuring Time Trend see page 132 Click Single to run the application Wh
232. ter separation The first method is based on spectrum analysis It is only possible when the data pattern is repetitive A clock waveform is always repetitive Other repetitive testing data patterns are used such as the K28 5 data pattern Patterns may have rather long repetition lengths for example the CJTPAT pattern is 2640 bits When using this method you must specify the pattern length and you will receive a warning if the pattern length appears to differ from that specified The second RJ DJ separation method known as arbitrary pattern analysis may be used when the data pattern is not necessarily repetitive This method works by correlating deterministic jitter observed over many repetitions with the bit pattern within a time domain window surrounding each observation RJ DJ Separation via Spectrum Analysis When the source waveform represents a repeating data pattern Deterministic Jitter DJ has a frequency spectrum of impulses The impulses due to the data pattern are equally spaced and occur at predictable frequencies related to the pattern length and bit rate Specifically the pattern related jitter impulse must occur at multiples of N where f is the data bit rate and N is the data pattern length Other spectral impulses may occur due to periodic jitter not correlated with the data pattern To obtain measurements of DJ and RJ all the components of the jitter spectrum that exceed the noise floor by a chosen margin are attributed t
233. th frequency and phase are optimized on the subsequent acquisition Jitter and Eye Diagram Analysis Tools Method Constant Clock Mean 94 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Constant Clock Median Table 47 Constant Clock Mean options Item Description Auto Calc First Acq Calculates the best fit of the initial acquisition or the first acquisition after clearing results and then uses the value until you clear the results Auto Calc Every Acq Calculates the best fit for each acquisition default Apply to All Apply Applies the current clock recovery configuration to all selected measurement s PLL Standard clock recovery options that have Clock Recovery as configuration tab Advanced Displays the Clock Recovery Advanced Setup see page 96 dialog box Constant Clock Median This method provides the following options that control how the clock recovery is performed B Auto Calc First Acq m Auto Calc Every Acq Selecting Autocalc First Acq will allow the clock recovery algorithm to choose a new best fit clock frequency and phase only on the first acquisition Subsequent acquisitions will choose a best fit on clock phase but retain the clock frequency found on the first acquisition Selecting Autocalc Every Acq will allow the clock recovery algorithm to choose a new best fit clock frequency and phase for each new oscilloscope acquisition Clearing the measurement resu
234. the maximum population which can be obtained for each active measurement OK Closes the window Related Topics Measurement Configuration Summary Measurement m Measurement Summary Ref Levels About Preferences Setup The applications provides Preferences Setup where you can set options These options remain unchanged until you reset them Click Analyze gt Jitter and Eye Analysis gt Preferences to view the Preferences screen To use the application more efficiently you can set the options in the following tabs Preferences General B Preferences Measurement Preferences Path Defaults Preferences General Click Analyze gt Jitter and Eye Analysis gt Preferences gt General to view the following DPOJET Jitter and Eye Diagram Analysis Tools 51 Operating Basics General Measw ement Path Defautts Table 22 Preferences General options Preferences General Item Description View Log Displays the error warning log file in a notepad window when the button is pushed Clear Log Clears the error warning log file when the button is pushed Display Units Selects the display units for time measurements between seconds or Unit Intervals Default Image Type Selects the default image format JPEG PNG or BMP that will be used by those functions that save images Notifier Duration Determines how long the Warning notifier will remain on the screen before disappearing The notifier may also
235. tions Item Description Select Target Measurements Displays the measurement list Select the check box to select the measurement By default all measurements are selected Select All Selects all the measurements in the list Clear All Deselects all the measurements in the list Log Statistics Off Disables automatic logging for all selected measurements On Enables automatic logging for all selected measurements File Name Browse Saves the csv file in the specified directory The file format is YYMMDD HHMMSS Stats csv The default directory is C NTekApplicationsNDPOJETNLogsNStatis tics 42 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Data Logging Measurement NOTE Microsoft Excel has a limitation where you cannot increase the number of rows 65 536 or columns 256 beyond the maximum row and column limits Opening log files in Wordpad or another analysis package is recommended An error message File not loaded completely is displayed if you try to open a log file with data exceeding the aforesaid row and column limits Related Topics m Data Logging Measurement Data Logging Worst Case Data Logging Measurement You can log the actual individual measurement data values as measurement files 1 Click Analyze gt Jitter and Eye Analysis gt Data Logging gt Measurement to view the Logging screen Statistics Measurement Worst Case Folder File
236. trum VERTical SCALE 00 ccc cece cece eee en nese ena eeeenaeeeenes 262 DPOJET PLOT lt x gt TRANSfer VERTical SCALE 0 0 c ccc ccc cece cee en emen 264 DPOJET PLOT lt x gt PHASEnoise BASEIine 0 ccc ccc cece cece eee eee eee 266 DPOJET Jitter and Eye Diagram Analysis Tools Index Table of Contents DPOJET PLOT x BATHtub VERTIcal SCALE sessssssseessse mene 266 DPOJET PLOT lt x gt EYE HORizontal RESolution 0 ccc ccc cece cece e ence nee reese eseese eeso 267 Reports DPOJET REPOR D eai a abcess ta dae Slaade ws R a N NEA 270 Logging DPOJET LOGging SNAPSHOE crore ida eee eoe epp n E E E aea RESTE ER 274 DPOJET LIMits DPOJEELEIMits S TATE 1 cttote ore bee ae n ee ete e ee ei tpa Ere d eee des ene 2T DPOJET LIMits FILEName eeceeeeeeeeeeeeesee he ehe ehe esses esses ere eee 277 DPOJET DESKEW 5 esscksttseexebt esa ve ra HE ERR Abr ENSE des Sasa ceeteuus oa den EEE ERE HERREN TERES 2T DPOJET dg uoc 281 DPOJETINUMMESS trio centre rem ette e pF IS EEE ERE med verte teda tie 282 DPOJET MEAS x DDR NPERCycle sssssssssesssssssese eene eese messen 282 DPOJET MEAS x DDR MPERCOycle 0 ccc cece ence een nnn me meme esse mese 282 DPOJET MEAS lt x gt DDR WINDOWSIZE 000 ccc ccc ccc e eme messem se se ener 283 DPOJET HIGHPerfrendermg eeseeeu eee rhe ee DURER re I eae Xx HU ERR RR E e TD dens 283 DPOJET UNIT TYP T irani i tisanes ti i i
237. ts either Linear or Log Syntax DPOJET PLOT x SPECtrum HORizontal SCALE Inputs LINEAR LOG Outputs LINEAR LOG NOTE Undefined for non spectrum plots DPOJET PLOT lt x gt SPECtrum BASE Sets or returns the spectrum base Undefined for non spectrum plots Syntax DPOJET PLOT lt x gt SPECtrum BASE Inputs lt NR3 gt Outputs lt NR1 gt DPOJET PLOT lt x gt SPECtrum MODE Sets or returns the spectrum mode DPOJET Jitter and Eye Diagram Analysis Tools 263 GPIB Commands DPOJET PLOT lt x gt TRANS fer VERTical SCALE Syntax DPOJET PLOT lt x gt SPECtrum MODE Inputs NORMal AVErage PEAKhold Outputs NORMal AVErage PEAKhold DPOJET PLOT lt x gt TRANSfer VERTical SCALE Sets or returns the vertical scale setting for applicable plots either Linear or Log Undefined for non transfer plots Syntax DPOJET PLOT lt x gt TRANSfer VERTiCal SCALE Inputs LINEAR LOG Outputs LINEAR LOG DPOJET PLOT lt x gt TRANSfer HORizontal SCALE 264 Sets or returns the horizontal scale setting for applicable plots either Linear or Log Undefined for non transfer plots Inputs LINEAR LOG Outputs LINEAR LOG DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET PLOT lt x gt TRANS fer MODE DPOJET PLOT lt x gt TRANSfer MODE Sets or returns the transfer plot mode Syntax DPOJET PLOT x TRANSfer MODE
238. ub curve Based on the bathtub curve the eye opening Width BER and eye closure TJ BER can be estimated for a given bit error rate The application calculates the eye opening at the specified BER using the following equation Eye opening 1 TJ BER when TJ BER is less than one Unit Interval Eye opening 0 when TJ BER exceeds one Unit Interval 206 DPOJET Jitter and Eye Diagram Analysis Tools Algorithms Jitter Estimation Using Dual Dirac Models Jitter Estimation Using Dual Dirac Models Jitter estimation based on RJ DJ separation depends in part on the specific jitter components modeled For the purposes of analyzing jitter and identifying root cause it is very useful to identify components as specifically as possible But for the purposes of determining compliance it has been found that a simplified jitter model yields results that are more consistent across different measurement instruments and different vendors A simplified model that has found acceptance in several industry standards is known as the Dual Dirac model This is because the probability density function PDF of all the deterministic jitter is replaced with a PDF consisting of two Dirac functions such that the total jitter and eye opening at very low bit error rates is unchanged The Random Jitter and Deterministic Jitter values derived from this model are identified as RJ 60 and DJ o6 respectively Two slightly different Dual Dirac models have been defined Both mode
239. ue is determined for each acquisition by means of RJ DJ separation analysis Related Topics B Jitter Analysis Through RJDJ Separation DPOJET Jitter and Eye Diagram Analysis Tools Algorithms Rise Time Rise Time The Rise Time measurement is the time difference between when the VRefHi reference level is crossed and the VRefLo reference level 1s crossed on the rising edge of the waveform The Rise Time algorithm uses the VRef values as the reference voltage level Each edge is defined by the slope voltage reference level threshold and hysteresis The application calculates this measurement using the following equation Re _ m _ piot TOTOO Where T Rise is the Rise Time T Hi 1s the VRefHi crossing on the rising edge TL 8 is the VRefLo crossing on the rising edge Fall Time The Fall Time measurement is the time difference between when the VRefLo reference level is crossed and the VRefHi reference level is crossed on the falling edge of the waveform The Fall Time algorithm uses the VRef values as the reference voltage level Each edge is defined by the slope voltage reference level threshold and hysteresis The application calculates this measurement using the following equation Th Ti T Where T Fall 1s the Fall Time T Le is the VRefLo crossing on the falling edge T Hi is the VRefHi crossing on the falling edge DPOJET Jitter and Eye Diagram Analysis Tools 183 Algorithms Skew S
240. ulate the effects of the PLL Jitter and Eye Diagram Analysis Tools PLL Standard BW qv PLL Model i a _ wji dard b s Loop BW PCI E 2 5G Table 50 PLL Standard clock recovery options I 1 5MHz Item Description PLL Model Selects between a Type or Type II phase locked loop Damping Use the keypad to specify the damping ratio of the PLL It is enabled only for Type II phase locked loop Loop BW Displays the bandwidth that has been selected based on the current standard Standard b s Implicitly sets the loop bandwidth of the clock recovery PLL based on selection of the industry standard and data rate in bits second Apply to All Apply Applies the current clock recovery configuration to all selected measurement s that have clock recovery as configuration tab Advanced Displays the Clock Recovery Advanced Setup For more details refer to the Clock Recovery Advanced Setup see page 96 PLL Custom BW The PLL control area provides control over the phase locked loop used for clock recovery You can choose the loop bandwidth and the loop order and if a Type II loop is chosen you can specify the damping factor To manually control the loop bandwidth select PLL Custom BW as the clock recovery method and use the User BW control to select the 3 dB bandwidth of the loop in Hz DPOJET Jitter and Eye Diagram Analysis Tools 99 Operating Basics About Explicit Clock Recovery You c
241. ulation is the total number of events or observations over which the other statistics were calculated Population X N Max cc The application calculates Max cc using the following equation Max cc X Max Xcc Where Xcc is the first difference of X Koo Ay 7 X4 Min cc The application calculates Min cc using the following equation Min cc X Min Xcc Where Xcc is the first difference of X Xoo 7 X Ay DPOJET Jitter and Eye Diagram Analysis Tools 209 Algorithms Results 210 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands About the GPIB Program About the GPIB Program You can use remote GPIB commands to communicate with the DPOJET application An example of a GPIB program that can execute the DPOJET application is included with the application in C NTekApplicationsNDPOJETNExamples The example shows how a GPIB program executes the application to do the following tasks 1 Start the application Recall a setup Take a measurement View measurement results and plots Ur ee Ue i9 Exit the application NOTE Commands are not case and space sensitive Your program will operate correctly even if you do not follow the capitalization and spacing precisely GPIB Reference Materials To use GPIB commands with your oscilloscope you can refer to the following materials The GPIB Program Example in C NTekApplicationsNDPOJETNExamples for guidelines to use while designing a GPIB program
242. ult in the detail view the limits will not be shown unless the limits are turned on Jitter and Eye Diagram Analysis Tools Period Refi 4 97 80ers 21 678ps 10 040ns 9 927 ns 112 24ps 40083 26 5938 28 635ps Result statistics for most of the measurements show Population in terms of UI or transitions According to the JEDEC specification the analysis for most of the clock measurements is done for a 200 cycle moving window However for clock measurements such as DDRtCL avg and DDRtCH avg the population is shown as tCK avg units For Data Eye Width the population number is shown as per acquisition DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Table 60 Results menu options Item e Viewing Statistical Results Description Displays an error message You can click e to view the error log information in a text editor A Displays a warning You can click A to view the error log information in a text editor Description Lists the measurement name and the source Mean Lists a statistical mean value for the measurement data Std Dev Lists a statistical standard deviation value for the measurement data Max Lists a statistical maximum value for the measurement data Min Lists a statistical minimum value for the measurement data p p Lists a statistical peak to peak value for the measurement data Population t Lists the total number of measurement data points used for displ
243. urces you need to use only math waveforms NOTE Setup Hold V DIff Xovr Common Mode and Skew are two source measurements The Source2 option is displayed only for two source measurements When more than one single source measurement is selected Apply to all single source measurements option is enabled in the source configuration screen Pen m When more than one two source measurement is selected Apply to all two source measurements option is enabled in the source configuration screen DPOJET Jitter and Eye Diagram Analysis Tools 63 Operating Basics Custom Source Name Setur Ir References Ch Math NOTE Custom measurement names Ex tDQSH are not displayed for DDRA selected measurements in the DPOJET source configuration screen Instead their DPOJET based Pos Width measurement names are displayed Related Topics m Source Autoset Ref Levels Custom Source Name Use a virtual keyboard to create a label for the selected waveform using the option Label under Vertical gt Label on your oscilloscope menu bar For more details refer to your oscilloscope online help Custom source names are displayed for both DPOJET and DDRA measurements The DPOJET application displays DQ Data Source and DQS Strobe A tool tip displays the Custom source name and the base source in brackets on moving the mouse over the row in the measurement table results
244. v DSL DOS iv tDS Diff base DOS DQ Measurement C TekApplications DPOJET Logs Statistics 081 021_045047_ Browse Data Logging and 66 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Custom Source Name Select Target Measurements Statistics Ej Data Eye Width iv tDH Diff base DOS DQ Worst Case tDQSH DOS tDOSL Dos iv tDS Diff base DOS DQ Measurement CTekApplicationsNDPDJE T Logs Statistics 081 021 044528 Browse B Measurement Summary Clock Recovery gt Method Explicit Clock Edge r peer Clock Source Ch1 Clock Edge Both Clock Multiplier et Levels 1 Clock Offset 625ps General gt Measurement a Data Eye With ba bos Range Limits Off Max ims Min 0s Custom Name Misc Data Eye Width Custom Source Name DQ CH3 DQS CH1 Edges gt Clock Edge Both Data Edge Both Filters gt F1 Spec No Filter F2 Spec No Filter General gt tDH Diff base DQS DQ Measurement Range Limits On Max 800ps Min Os Custom Name tDH Diff base Custom Source Name DQS CH1 DQ CH3 Filters gt F1 Spec No Filter F2 Spec No Filter General gt Measurement Range Limits Off Max 1ms Min 1ps Custom Name tDQSH Custom Source Name DQS CH1 Filters gt F1 Spec No Filter F2 Spec No Filter General gt Measurement Range Limits Off Max 1ms a E Export Results to Ref DPOJET Jitter and Eye Diagram Analysis Tools 67
245. vector is filtered Blanking Time Duration of the filter s output that is suppressed The blanked portion of the output is not included in the measurement statistics or in any plots OK Accepts changes and closes About Clock Recovery Clock recovery refers to the process of establishing a reference clock the edges of which can be used as a basis for timing comparisons The Clock Recovery configuration tab allows you to select one of the following clock recovery methods Constant Clock Mean Constant Clock Median Constant Clock Fixed m Phase Locked Loop Standard BandWidth BW Phase Locked Loop Custom BandWidth B Explicit Clock Edge m Explicit Clock PLL The first four methods derive the reference clock from the same channel upon which the measurement is defined This is the conventional method of clock recovery for serial data communications where no separate clock is available The last two methods Explicit Clock derive the reference clock from a channel other than the one upon which the measurement is defined About Constant Clock Recovery In Constant Clock Recovery the clock is assumed to be of the form A sin 2II ft where the frequency f and phase are treated as unknown constants Once a source waveform has been acquired and the edges extracted one or both of these constants are determined using linear regression so that the recovered clock minimizes the mean squared sum of the Time Interval
246. wing command buttons m Perform Deskew B Summary Option Parameters Default setting Reference Channel Source Ch1 Ch2 Ch3 Ch4 Ch1 Mid 20 V to 20 V 0v Hysteresis 0 to 10 V 30 mV Channel to be Deskewed Source Ch1 Ch2 Ch3 Ch4 Ch2 DPOJET Jitter and Eye Diagram Analysis Tools 157 Parameters Data Logging Parameters Option Parameters Default setting Mid 20 V to 20 V OV Hysteresis 0 to 10 V 30 mV Edges Rise Fall Both Rise Deskew Range Max Value 24 9 ns to 25 ns 1 ns Min Value 25 0 ns to 24 9 ns 1 ns Data Logging Parameters The application includes the following Log menus Statistics Measurement Worst Case Option Parameters Default Statistics Select Target Measurements Set Clear Set Log Statistics Off On Off File Name Browser C NTekApplicationsNDPO JET Logs Statistics Measurement Select Target Measurements Set Clear Set Log Measurements Off On Off Folder Browser C NTekApplicationsNDPO JET Logs Measurements Worst Case Select Target Measurements Set Clear Set Log Worst Case Waveforms Off On Off Folder Browser c TekApplications DPO JET Logs waveforms Control Panel Parameters The Control Panel menu includes the following command buttons m Clear Recalc 158 DPOJET Jitter and Eye Diagram Analysis Tools Parameters Bit Config Parameters B Single Run Show Plots NOTE Show Plots app
247. x gt BASETop MINMax FULLhistogram EYEhistogram AUTO Inputs MINMax FULLhistogram EYEhistogram AUTO Outputs MINMax FULLhistogram EYEhistogram AUTO DPOJET Jitter and Eye Diagram Analysis Tools 239 GPIB Commands DPOJET REFLevels CH lt x gt ABsolute DPOJET REFLevels CH lt x gt ABsolute The ABSolute branch specifies the ref levels in the event a user chooses not to run a ref level autoset on a given source In the event the user does run a ref level autoset the percentage values of Rise Fall and Hysteresis are used DPOJET REFLevels CH lt x gt ABsolute RISEHigh Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt ABSolute RISEHigh Inputs lt NR3 gt Outputs lt NR3 gt DPOJET REFLevels CH lt x gt ABsolute RISEMid Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt ABsolute RISEMid Inputs lt NR3 gt Outputs lt NR3 gt 240 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET REFLevels CH x ABsolute RISELow DPOJET REFLevels CH lt x gt ABsolute RISELow Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH lt x gt ABsolute RISELow Inputs lt NR3 gt Outputs lt NR3 gt DPOJET REFLevels CH lt x gt ABsolute FALLHigh Sets the ref level voltage relative to base top for autoset Syntax DPOJET REFLevels CH x ABs
248. y of the jitter measurements are based on the concept of RJ DJ separation The application begins with the measured Jitter versus time as represented by the TIE measurement array and analytically determines the random and deterministic components of the jitter The deterministic part is further separated into independent subcomponents with specific characteristics The random jitter RJ is assumed to be zero mean Gaussian and is assumed to have a flat spectrum when viewed in the frequency domain The measured RJ is fitted to a Gaussian mathematical model which is parameterized by its standard deviation Using the mathematical model for RJ statistically probable jitter extremes may be predicted for much greater populations than actually measured The deterministic jitter DJ is predictable and can be generated consistently given known circumstances The various DJ measurements each report the peak to peak value of the corresponding DJ subcomponent Once all the jitter components have been identified and the random jitter has been converted to a mathematical model the components can be reassembled such that performance may be extrapolated to extremely low bit error rates The probabilistic Total Jitter TJ BER and probabilistic Eye Width Width BER are examples of such measurements The reported values are predictions that correspond to a user specified Bit Error Rate rather than observed values Two approaches are supported for performing jit
249. ycle You can set window size up to 1M with a minimum of 200 116 DPOJET Jitter and Eye Diagram Analysis Tools Operating Basics Jitter and Eye Diagram Analysis Tools AV Measurement Source s DDR tCH avg t Ren DDR tcL ava 1 LZ I Configuring Edges for DDR tERR m n Edges Filters General Configuring Edges for DDR tERR m n This configuration tab is displayed for DDR tERR m n measurement Jitter and Eye Diagram Analysis Tools Edges Number of Periods Clock Edge Minimum D Maximum 10 General Global Window Size 200 Item Description Clock Edge Rise Measurements are only initiated on the Rising edges of the clock signal Fall Measurements are only initiated on the Falling edges of the clock signal Number of Periods Minimum Specify the minimum number of periods required to calculate error across multiple consecutive cycles from tCK avg Maximum Specify the maximum number of periods required to calculate error across multiple consecutive cycles from tCK avg Window Size Measurement analysis is done on a window of size 200 DPOJET Jitter and Eye Diagram Analysis Tools cycles with a step increment of 1 cycle As per the standard the default window size is 200 You can set window size up to 1M 117 Operating Basics Configuring Edges for DDR tERR n Configuring Edges for DDR tERR n This configuration tab
250. ye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt LOGging MEASurements FILEname Outputs 1 0 DPOJET MEAS lt x gt LOGging MEASurements FILEname Queries current file name that will be used for the measurement should measurement logging be turned on Syntax DPOJET MEAS lt x gt LOGging MEASurements FILEname Outputs String DPOJET MEAS lt x gt LOGging WORSTcase SELect Sets or queries the given measurement for inclusion in any worst case logging Statistic logging is turned on or off as a whole using the DPOJET LOGging branch Syntax DPOJET MEAS x LOGging WORSTCase SELect Inputs 1 0 Outputs 1 0 DPOJET GATING Sets or queries the gating state DPOJET Jitter and Eye Diagram Analysis Tools 233 GPIB Commands Syntax DPOJET GATING Inputs OFF ZOOM CURSORS Outputs OFF ZOOM CURSORS DPOJET QUALify STATE Turns on or off measurement qualification Syntax DPOJET QUAL i fy STATE Inputs 1 0 Outputs 1 0 DPOJET QUALify SOUrce 234 Sets the qualifier source Syntax DPOJET QUAL i fy SOUrce Inputs DPOJET QUALify STATE CH1 CH4 MATH1 MATH4 REF1 REF4 SEARCH1 SEARCH8 DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET QUALify ACTIVE Outputs CH1 CH4 MATH1 MATH4 REF1 REF4 SEARCH1 SEARCH8 DPOJET QUALify ACTIVE Sets the active state for the qualifier source either HIGH or LOW Syntax DPOJET
251. ye Diagram Analysis Tools Operating Basics Source Autoset Follow these steps to automatically define the vertical or horizontal settings for active sources 1 Ensure that any channel waveform that you want to autoset is visible on the oscilloscope 2 For Vert amp Horiz and Horizontal resolution the edge resolution is configured for five samples per edge or more for better edge timing and measurement accuracy 3 Select one of the following options Vert amp Horiz to autoset both vertical and horizontal setting Vert Scale button to autoset oscilloscope vertical settings only Horiz Res to autoset oscilloscope horizontal settings only Source Configuration Pen wl Table 29 Autoset configuration options Undo to return the oscilloscope to its state before autoset Item Description Vertical Scale If a channel waveform does not exceed six vertical divisions decreases the scale so that the waveform occupies about eight divisions Horiz Res Sets the horizontal resolution so that the number of samples on the fastest transition edge exceeds a specified target Vert amp Horiz Performs a sequence Oscilloscope Autoset Vertical scale and Horizontal resolution Undo Returns to the settings present before an Autoset was performed disabled after measurements are taken until you perform another source autoset Ref Levels Setup Click Ref Levels Setup in the Source Configuration scree
252. yntax DPOJET MEAS lt x gt FILTers RAMPtime Inputs lt NR3 gt Outputs lt NR3 gt DPOJET MEAS lt x gt FiLTers BLANKingtime Sets or queries the current filter blanking time Syntax DPOJET MEAS x FILTers BLANKingtime Inputs NR3 Outputs NR3 DPOJET MEAS lt x gt FiLTers HIGHPass SPEC Sets or queries the current high pass filter specification DPOJET Jitter and Eye Diagram Analysis Tools 219 GPIB Commands DPOJET MEAS lt x gt FILTers HIGHPass FREQ Syntax DPOJET MEAS x FILTers HIGHPass SPEC NONE FIRST SECOND THIRD Inputs NONE FIRST SECOND THIRD Outputs NONE FIRST SECOND THIRD DPOJET MEAS lt x gt FiLTers HIGHPass FREQ Sets or queries the current high pass filter frequency Syntax DPOJET MEAS lt x gt FILTers HIGHPass FREQ Inputs lt NR3 gt Outputs lt NR3 gt DPOJET MEAS lt x gt FiLTers LOWPass SPEC 220 Sets or queries the current low pass filter specification Syntax DPOJET MEAS x FILTers LOWPass SPEC NONE FIRST SECOND THIRD Inputs NONE FIRST SECOND THIRD DPOJET Jitter and Eye Diagram Analysis Tools GPIB Commands DPOJET MEAS lt x gt FILTers LOW Pass FREQ Outputs NONE FIRST SECOND THIRD DPOJET MEAS lt x gt FiLTers LOWPass FREQ Sets or queries the current low pass filter frequency Syntax DPOJET MEAS lt x gt FILTers LOWPass FREQ Inputs lt NR3 gt Outputs lt NR3 gt DPOJ

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