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User Manual VM700T Video Measurement Set Option 20 Teletext

1. Threshold EyeHeight at Clock at XX5 defines a timing point for the Eye Height measurement relative to the clock position as a percentage of the clock period The position of the clock is the default To change the position of the timing point touch and hold the soft key and turn the knob EyeHeight at Max searches all timing positions and returns the maximum eye height result EyeWidth at Middle at XX defines a voltage level at which to make the Eye Width measurement as a percentage of the difference between the 0 and 1 levels The mid point between the 0 and 1 levels is the default To change the voltage level touch and hold the soft key and turn the knob EyeWidth at Max searches all positions and returns the maximum eye width result Threshold selects the number for the threshold to determine eye height and eye width values The value selected shows the proportion of extreme values omitted from the Histogram display for the eye height and eye width measurements VM700T Option 20 Teletext Measurements User Manual 2 9 Operating Basics Cursors Submenu Voltage Voltage Cursor On displays voltage cursors Two horizontal Cursor On cursors appear where they were when voltage cursors were last active Timing Timing Cursor On displays timing cursors Two vertical Cursor On cursors appear where they were when timing cursors were last active Cursor Cursor Relative selects relative cursor mode When Relat
2. FAX 781 665 0780 TestEquipmentDepot com Operating Basics Measurement Location for the Teletext Measurement Field 1 Line 17 Synchronous Teletext Set Run_in Exit Default 12 0uSec Figure 2 6 Teletext Special Position display Special Position Submenu Set Default Set Default resets the location for the run in bits to the default position specified in the current Measurement Locations file Run In Run In selects the location for the run in bits Exit Exit leaves the Measurement Locations display and returns to the Eye Measurement display VM700T Option 20 Teletext Measurements User Manual Operating Basics SoundInSync Eye Measurement Display 2 12 The SoundInSync Eye Measurement display Figure 2 7 appears when the SoundInSync soft key is pressed This display shows the name of the measure ment the type of waveform being measured and the line number being measured Sound In Sync Line 60 SIS mode Level mV 500 0 450 400 Eye Threshold 1 250 Eye Height 90 5 359 183 1 mv 300 At Clock 250 0 Eye Width 60 6 200 At Middle 150 0 3 Level 368 2 mv 109 2 Level 132 7 mv 50 1 Level 69 6 mv 0 07 0 Level 301 1 mv 50 0 P P Amp 105 2 amp L5 704 4 mv 100 07 150 07 200 07 250 04 300 350 400 450 Persistence 128 Wfms Accumulation 1640 times Figure 2 7 SoundInSync Eye display The graphical display portion of the screen show
3. which to make the Eye Width measurement The mid point between the 0 and 1 levels is the default To change the voltage level at which the measurement is made touch and hold the soft key and turn the knob The position of the voltage level is given as a percentage of the difference between the 0 and 1 levels EyeWidth at Max searches all positions and returns the maximum eye width result VM700T Option 20 Teletext Measurements User Manual Operating Basics Clock F Clock F selects the clock frequency 352 or 382 times the line 382 Fh frequency Threshold Threshold selects the number for the threshold to determine eye height and eye width values The value selected shows the proportion of extreme values that will be omitted from the Histogram displays for the eye height and eye width measure ments Cursors Submenu Voltage Voltage Cursor On displays voltage cursors Two horizontal Cursor On cursors appear in the positions they were in the last time voltage cursors were active Timing Timing Cursor On displays timing cursors Two vertical Cursor On cursors appear in the positions they were in the last time timing cursors were active Cursor Cursor Relative selects relative cursor mode When this soft Relative key is highlighted the cursor delta is displayed as a percentage of a user definable voltage or timing distance When this soft key is not highlighted the cursor delta is displayed in millivolt
4. Eye display ies es ss SS Se ee ee 2 12 Figure 2 8 SoundInSync Histogram display 000 2 14 Figure 2 9 SoundInSync menu tre ee eese 2 15 Table 3 1 Button Names sssessseseeee eee de ee 3 3 Table 3 2 J Group Keywords Teletext Configuration NTSC 3 5 Table 3 3 K Keywords Teletext Configuration PAL 3 6 VM700T Option 20 Teletext Measurements User Manual UAR Preface The VM700T Video Measurement Set Option 20 Teletext gives you access to two additional measurements Teletext and SoundInSync These measure ment applications determine various parameters related to the transmission of digital information in the vertical interval and in the sync pulse respectively The manual contents are arranged as follows Configuring the Option describes how to configure the Teletext Measurement option of the VM700T Video Measurement Set Operating Basics describes operation of the VM 700T Video Measurement Set Teletext option Teletext measures parameters related to the transmission of digital information in the vertical interval of a teletext signal SoundInSync measures parameters related to the transmission of digital information in a sound in sync pulse The measurements menus and displays for these features are found in this section Remote Commands and Keywords describes the remote commands and keywords that are added to perform the option measurements
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6. keywords take different arguments depending on the keyword VM700T Option 20 Teletext Measurements User Manual 3 5 Remote Commands and Keywords Table 3 3 K Keywords Teletext Configuration PAL Keyword Description Keyword Description KOLV 0 Level mV KRIS Run In Start usec K1LV 1 Level mV KSOL SoundinS ync 0 Level mV KDES Data End to Sync usec KSIL SoundinS ync 1 Level mV KDLW Data Line Width usec KS2L SoundinS ync 2 Level mV KDTM Data Timing sec KS3L SoundinS ync 3 Level mV KEHM Eye Height mV KSHM SoundinS ync Eye Height mV KEHP Eye Height 96 KSHP SoundinS ync Eye Height 96 KEWP Eye Width 96 KSPM SoundlInS ync P P Amplitude mV KPPM P P Amplitude mV KSPP SoundinS ync P P Amplitude 96 KPPP P P Amplitude 96 KSWP SoundinSync Eye Width KRIA Run In Amplitude mV KTTL Teletext line KRIB Run In Bits bits Function Key Special Feature 3 6 A special feature has been added to enable Teletext and SoundInSync measure ments on scrambled video signals With scrambled video signals the sync level is altered from that of normal video by a 350 mV bar in the backporch area The Teletext and SoundInSync measurements of the VM 700T assumes normal video sync levels and clamps the signal at the back porch With scrambled video the normal clamp lowers everything by 350 mV and so prevents the measurements from being made correctly The VM 7
7. of time omitted on the display to allow as much of the interesting portion of the signal as possible to be displayed at one time The omitted portion of the signal is represented by two jagged vertical lines Moving the display rightward reduces the amount of time omitted When the amount of time omitted goes to zero the jagged lines disappear from the display Another pair of digital readouts show the amplitude and number of run in bits that precede the digital information in the teletext signal VM700T Option 20 Teletext Measurements User Manual Operating Basics Readouts show the amount of time from the start of the run in bits to the end of the digital data and from the end of the digital data to the 50 point of the leading edge of sync for the next line Teletext Timing NTSC Wim gt Teletext Field 1 Line 17 440 9 mv Average Off Figure 2 2 Teletext timing display A horizontal line of small dots appears at the level of the mean amplitude of the run in bits These dots show the position of clock edges for the digital data These dots can be used to determine whether a 0 or 1 is being transmitted at any point in the digital data sequence VM700T Option 20 Teletext Measurements User Manual 2 3 Operating Basics Teletext Eye Measurement Display 2 4 The Teletext Eye Measurement display Figure 2 3 also shows the name of the measurement the type of waveform being measured and the fie
8. return to the Configure menus VM700T Option 20 Teletext Measurements User Manual Configuring the Option Configuring the Video Source Files If the system default Channel Configuration file for video sources is acceptable the VM 700T uses this file as it performs video measurements In the System Default Video Source File shown in Figure 1 7 choices for the installed options needing video sources are listed This file is not editable If you must select a source file other than the default file selection you will have to create a new file that can be edited To modify file parameters you must do the following create a file select the existing file to be used as a template name the file you created edit the information in the new file as needed accept the edits save the changes Channel Configuration System Default File Auto Limits File Measure Limits File Measurement Location File Selected Measurement File Auto Sync Source Source Name Video Printout Title EndToEnd System Default System Default System Default Locked to Source Locked to Source VM700T Video Measurement Set Options Echo and Rounding System Default Teletext System Default Component System Default Line 15 Showing rom ConfigFiles Video Source Files NTSC System Default No Change amp Exit Figure 1 7 Channel Configuration System Default file VM700T Option 20 Teletext Measu
9. soft key 1 8 Limit file deleting 1 8 Index 2 M Main Menu Average Num 2 6 Eye Meas 2 6 Rescale 2 6 SoundInSync 2 14 Teletext 2 7 measurement results files SoundInSync 1 12 Teletext 1 12 N name list front panel buttons 3 3 naming files 1 6 No Change amp Exit soft key 1 8 1 10 1 12 P P P Amplitude 2 12 P P amplitude 2 4 parameters changing Video Source file 1 10 Persistence 2 12 persistence 2 4 R remote control command format 3 2 S scrambled video 3 6 set VM700T Command 3 3 show VM 700T Command 3 4 soft keys Accept Input 1 7 1 11 1 12 Cancel 1 8 Configure Files 1 2 Delete 1 8 Done 1 7 Leave Directory 1 8 No Change amp Exit 1 8 1 10 1 12 Source Selection Video 1 11 System Default 1 6 Update amp Exit 1 8 softkey VM700T Command 3 4 Sound In Sync Eye Display 2 11 Sound in Sync menu 2 14 VM700T Option 20 Teletext Measurements User Manual Index SoundInSync Cursors Menu Cursor 1 Active 2 16 Cursor 2 Active 2 16 Relative Cursor 2 16 Set 100 2 16 Timing Cursor 2 16 Voltage Cursor 2 16 SoundInSync Eye Measurement display Submenu Full Histogram 2 15 Grading Display 2 15 Histogram Reset 2 15 Historgram at Clock 2 15 Persistence 2 15 Waveform Display 2 15 SoundInSync Eye Measurement Parameters Submenu Clock Frequency 2 16 Eye Height at Clock 2 15 Eye Height at Max 2 15 Eye Width at Max 2 15 Eye Width at Middle 2
10. the position of the timing point touch and hold the soft key and turn the knob The position of the timing point is given relative to the clock position as a percentage of the clock period Grading Grading Display shows accumulative waveform information Display Larger accumulations yield better results Waveform Waveform Display shows the most recent waveforms and Display brings up the Persistence soft key to select the number of waveforms displayed Persistence Persistence selects the number of waveforms to be shown in the Waveform display This value can be varied in powers of two from 4 to 1024 plus zero no persistence and infinite all waveforms displayed To change the Persistence value touch the soft key to highlight it then turn the knob Histogram Histogram Reset clears all accumulated waveforms and Reset restarts the eye measurement Eye Measurement Parameters Submenu EyeHeight at Clock EyeHeight at Max EyeWidth at Middle EyeWidth at Max EyeHeight at Clock at XX defines a timing point for the Eye Height measurement The position of the clock is the default To change the position of the timing point touch and hold the soft key and turn the knob The position of the timing point is given relative to the clock position as a percentage of the clock period EyeHeight at Max searches all timing positions and returns the maximum eye height result EyeWidth at Middle at XX defines a voltage level at
11. 00T firmware permits these measurement to be made The procedure requires that the measurements be called from a Function Key The means to accomplish the necessary modification is the addition of a variable clampOffset appset command that restores the sync to the proper level to make the measurement Full information on creating and editing Function Keys is found in the VM 700T RS 232 Interface Programmer Manual A brief outline is given here to explain the addition of the command to the Function Key file after it has been created The steps are as follows 1 Press the Configure button and select Function Keys 2 Create a Function Key that calls the Teletext or SoundInSync measurement as appropriate to your application See Creating Functions in the VM 700T RS 232 Interface Programmer Manual VM700T Option 20 Teletext Measurements User Manual Remote Commands and Keywords 3 Editthe Function Key file you have created to add the special appset that adjusts the sync level see Editing Functions in the VM 700T RS 232 Interface Programmer Manual At the end of all other appsets for the measurement add one of the following lines as appropriate appset clampOffset NTSC 350 for NTSC users or appset clampOffset 350 for PAL users If no other appset command lines appear in the Function Key file place it just after the line that executes the measurement 4 Update amp Exit the Function Key file When the Function Key you h
12. 15 Threshold 2 16 SoundInSync Main menu Cursors 2 14 Display 2 14 Eye Measurement Parameters 2 14 Rescale 2 14 SoundInSync softkey 1 1 source channel selection file 1 11 Source Selection Video file 1 1 soft key 1 11 Special Position Submenu Exit 2 10 Run In 2 10 Set Default 2 10 Teletext 2 10 system default source channel selection 1 11 teletext option configuration NTSC 1 4 system default files 1 3 VM700T Option 20 Teletext Measurements User Manual system default screens 1 3 System Default soft key 1 6 T Teletext File 1 3 Teletext Limit changing parameters 1 7 Teletext Limits file creating 1 5 Teletext limits changing 1 7 Teletext Measurement limit file 1 1 changing 1 3 Teletext softkey 1 1 Teletext Timing Measurement display 2 1 template existing file used as 1 3 U units of measure defaults 2 4 Update amp Exit soft key 1 8 V Video Limit file changing parameters 1 3 Video Options directory viewing 1 1 Video Source file 1 1 configuring 1 9 editing 1 10 specifying 1 11 Video Source Files 1 9 Video Source file changing 1 9 VM700 prompt 3 2 VM700T Commands execute 3 2 get 3 2 getresults 3 3 hardkey 3 3 set 3 3 show 3 4 softkey 3 4 Index 3 Index Index 4 VM7007T Option 20 Teletext Measurements User Manual Test Equipment Depot 800 517 8431 99 Washington Street Melrose
13. 2 1 Operating Basics In nvram0 Executable Files Video Options Audio Video Camera Testing Component Timing z Echo Rounding Teletext i i i Video Previous Leave ida Audio Diags Options Selection Directory Note In the first Measure mode menu display the Video soft key is visible when Video Options are sel and the Video Options soft key is visible when when Video is selected The Audio soft key is seen only Audio Options are installed Figure 2 1 Measure Mode menu choices Teletext Timing Measurement Display The Teletext Timing Measurement display Figure 2 2 shows the name of the measurement the type of waveform being measured and the field for NTSC and line number being measured The graphical display portion of the screen shows the signal being measured For NTSC a digital readout in the upper left portion of the display shows the amount of time from the 50 point of the leading edge of sync to the 50 point of the start of the run in bits For PAL the same digital readout shows the amount of time from the 50 point of the leading edge of sync to the Data Timing Reference point This reference point is defined as the time of the peak of the next to last 1 bit in the clock run in sequence Another digital readout in the lower left portion of the display shows the amount
14. 6 Teletext Menu op E EIER NEM Ee De rd 2 7 Mam Menu eve EIER UD RP ERRRUUODRPLDERS te eee nes 2 7 Eye Measurement Submenu lees 2 7 Display Submenu oa Er GR AE Ee seu cea eee Reade ead T PR NAR ERA 2 8 Eye Measurement Parameters Submenu 00 20005 2 9 Cursors Submenu ore N eb RE Ree rbd oes 2 10 Acquire Submenu EE EE cect ee ee ee ee ee N 2 10 Special Position Submenu sll 000 cee cece eee 2 11 SoundInSync Eye Measurement Display is se Ge GE Ge Ge es ee 2 12 SoundInSync Histogram Display is se ss Ge Ge cece eee 2 14 SoundInSyne Menu eseseeeeeee e e 2 15 EA Re ER AE ET ER Mee phat See ee TE eae T 2 15 Display Submenu 20 cece e 2 16 Eye Measurement Parameters Submenu ss es ee 2 16 Cursors SUDMENU Lee ON He EEUU e ene 2 17 Remote Commands and Keywords Command Format eec OUR RD SCA I e hag UR LR RICE A 3 2 Teletext measurement Remote Commands 02 eee eee eee 3 2 execute application x xut uso eiue pre UO ON EIA RS CEN ENS 3 2 get keyword channel letter 2 2 3 2 Betresults SE EER BR AR Baers Te ue PERS MR vea S Ere ttes 3 3 VM700T Option 20 Teletext Measurements User Manual i Table of Contents Index List of Figures List of Tables hardkey button name lseeeeeee ete 3 3 set keyword channel letter valuel value2 ess 3 3 RAU AE RE hoe c dx RR dE ERE 3 4 softk
15. Graticule Vector B Helps Waveform Cc Men XY Arrow selector Copy MoveExpand NOTE The Configure Function and Measure buttons cannot be selected from remote set keyword The set command defines the configuration values to be used during the remote channel letter value1 session The keywords available to use with set are listed in Table 3 1 value2 Table 3 2 and Table 3 3 The channel letter can be A B or C The configura tion values changed with set remain in effect until they are restored to their original preremote values with the restoreconfig command or power to the instrument is switched off and back on Note that the system line and other global variables can be changed with set but are not restored with the restoreconfig command VM700T Option 20 Teletext Measurements User Manual 3 3 Remote Commands and Keywords show filename softkey softkey name 3 4 Example VM700 gt set JPPP A 110 00 190 00 The above example changes the NTSC Teletext peak to peak amplitude for channel A from its previous values to 110 00 to 190 00 percent The show command returns the contents of the specified filename The default path is the Measurement Results directory but other files can be specified with a full pathname or a path relative to the Measurement Results directory Example VM700 show nvramO ConfigFiles Source Selection Video Video NTSC Video Source File Name PAL Video Source F
16. Test Equipment Depot User Manual 1 800 517 8431 Tektronix 7 VM700T Video Measurement Set Option 20 Teletext Measurements 070 9652 01 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com IINE AEDEM Table of Contents Preface vs hic eis Ale ehhh She a eS UR Re RUE ES EN M iii Configuring the Option Configuring the Teletext Measurement Limit File i s se ses Se sees 1 3 Create a Teletext Measurement Limits File sesse Ses See sees 1 5 Editing a Teletext Measurement Limit Text Parameter 1 7 Deleting a Teletext Measurement Limit File 4 1 8 Configuring the Video Source Files 0 0 eee eee eee eee 1 9 Editing the Video Source File 2 2 ununura eee eee eee 1 10 Changing the Video Source Parameters 00 00 eee eee ee eee 1 10 Configuring the Source Selection Video Files 00020 0000 1 11 Specifying a Video Source File 2 2 0 0 0 0 e eee eee 1 11 Measurement Results Files ee GE GE ese ee ee Ge eee eens 1 12 Operating Basics Function Key Special Feature esse Ge Ge Gee ee ee eens 2 1 Measure Mode Menu Operation es EG EG Ee ee Ge Ge eee eee 2 1 Teletext Timing Measurement Display sees 2 2 Teletext Eye Measurement Display ss GE es ss se esee ess 2 4 Teletext Histogram Display ssseseseeese Ge ee ee ee ee 2
17. _Selection Video displays 2 Touch the Source Selection Video soft key The Source_Selection Video file is then seen 3 Rotate the front panel knob to highlight the source for which you are specifying a Video Source file source A B or C 4 Touch the highlighted source file to select it A box highlights the selected file 5 Rotate the front panel knob to change the Video Source file selection 6 Touch the Accept Input soft key The highlight box disappears and the new source displays VM700T Option 20 Teletext Measurements User Manual 1 11 Configuring the Option 7 Touch the Update amp Exit soft key if the change is correct The ConfigFiles menu displays If the change is not correct touch the No Change amp Exit soft key NOTE If you change the Video Source file and do not want to save the change touch the Accept Input soft key then touch the No Change amp Exit soft key The VM 700T asks you to touch the No Change amp Exit soft key again to verify that you want to exit the Source Selection Video directory and cancel any changes Measurement Results Files 1 12 The measurement results for Teletext and SoundInSync for PAL and dual stan dard instruments are kept in the Measurement Results files The results of the most recent measurement are stored here and can be viewed by selecting the Teletext or the SoundInSync results file The following displays see Figure 1 9 and Figure 1 10 show examp
18. and get measurement results Abbreviated instructions for operating the instrument using remote control are also found in this section For more complete information about remote control see the VM700T RS 232 Interface Programmer Manual If you have Option 48 the GPIB interface option installed refer also to the VM700T Option 48 GPIB Interface Programmer Manual for added information on GPIB remote operation VM700T Option 20 Teletext Measurements User Manual iii NU CINES Configuring the Option This section describes how to configure the Teletext Measurement option of the VM700T Video Measurement Set The Teletext soft key appears in the Video Options directory window when Option 20 is installed in your VM700T The SoundInSync soft key appears in the Video Options directory window when Option 20 is installed in your VM700T with PAL or dual standard software To view the Video Options directory window press the Measure button on the front panel If the VM700T was in the Video Options directory when you last used Measure Mode the Video Options directory will be displayed Otherwise press the Video Options soft key at the bottom of the display to view the Video Options directory Configuring the VM700T Teletext Measurement option is similar to using its other video functions A series of files and directories provide default parameters that the VM 700T uses to measure video signals If your application requires parameters other than the de
19. ave just created runs the added clamp offset line adjusts the backporch clamping so the Teletext or SoundInSync measurement is done at the proper level VM700T Option 20 Teletext Measurements User Manual 3 7 Index Numbers 0 Level 2 712 1 Level 2 12 2 Level 2 12 3 Level 2 12 A Accept Input soft key 1 11 1 12 Accumulation 2 12 accumulation 2 4 Acquire Submenu V Phase Only PAL 2 9 clock frequency 2 9 Special Position 2 9 Teletext 2 9 V Phase Only PAL 2 9 appset 3 7 arrows 2 12 B backporch clamping 3 7 button names list of front panel 3 3 buttons Configure 1 1 C Cancel soft key 1 8 changing signal level 2 12 changing Video Source file 1 9 1 10 clampOffset 3 7 clock cycle accumulation in Teletext Eye Measure ment display 2 5 clock cycles 2 11 2 13 command format 3 2 configuration begin 1 1 steps 1 1 Configure button 1 1 Configure Files soft key 1 2 configuring Video Source files 1 9 Cursors Submenu Cursor 1 Active 2 9 Cursor 2 Active 2 9 Cursor Relative 2 9 Set 10096 2 9 VM700T Option 20 Teletext Measurements User Manual SoundInSync 2 16 Teletext 2 8 Timing Cursor On 2 9 Voltage Cursor On 2 9 D Delete soft key 1 8 deleting a limit file 1 8 digital readouts in display 2 1 display features 2 2 Teletext eye measurement 2 3 Display Submenu Full Histogram 2 7 Grading Display 2 8 Histogram at Clock At XX 2 7 Histogram Res
20. e configure menu 2 Touch the Configure Files soft key to begin configuration The screen displays a series of options in a window as shown in Figure 1 2 Scroll the window to view the Teletext choices by turning the front panel knob Audio Limit Audio Source Audio Source Files Files Identification Auto Limit Camera Communi cation Files Testing Setup C Diagnostics Diagnostic omponent Selection Errors Measure Limit Measurement Echo Rounding Faresa li ins i Files Locations A NTSC Files In nvram ConfigFiles Switch Print Leave NTSC PAL File Directory Figure 1 2 Configure menus options VM700T Option 20 Teletext Measurements User Manual Configuring the Option Configuring the Teletext Measurement Limit File Touch the Teletext soft key to enter the Teletext Measurement limit file directory The screen displays the system default file and if any have been created user limit files see Figure 1 3 You can touch a soft key to display the parameters in any file but parameters of the system default files cannot be changed The system default files shown in Figure 1 4 and Figure 1 5 are used to describe the measurement limits and sources for the Teletext and SoundInSync auto measurements The control knob is used to scroll the c
21. e the VM 700T RS 232 Interface Programmer Manual The programmer manual discusses the VM 700T RS 232C port requirements in detail and shows typical cable wiring configurations For information on using GPIB for remote operation see the VM 700T Option 48 GPIB Interface Programmer Manual Capabilities available while operating the VM 700T from a remote location include m making a specific manual measurement or Auto mode set of measurements W executing and interrupting a function Function Key m changing temporarily the configuration of a channel limit files selected measurement files and measurement location files printer type and port for each type of output Copy Report Log m specifying an End of File character for printer output The remote commands used to access the Teletext measurement functions are the same as those used for other VM 700T functions The command arguments are listed and described below The information in this section assumes that you are familiar with manual operation of the VM 700T and understand the principles of remote VM 700T operation For information on working with VM 700T remote control commands see the VM 700T RS 232 Interface Programmer Manual NOTE Rather than being a complete discussion the following material is an abbreviated explanation of the remote commands It assumes that you under stand the principles of remote VM 700T operation and have access to the VM700T RS 232 Interface Progra
22. ease the value of a parameter 4 Touchthe Accept Input soft key to accept the change The highlight box disappears and the new parameter displays VM700T Option 20 Teletext Measurements User Manual 1 7 Configuring the Option 1 8 Deleting a Teletext Measurement Limit File NOTE If you change a parameter and do not want to save the change touch the No Change amp Exit soft key The VM 700T asks you to touch the No Change amp Exit soft key again to verify that you want to exit without changing anything To display the file you created touch its soft key When making extensive changes to a file avoid losing changes by touching the Update amp Exit soft key after each change then re enter the file That way if you make a mistake and must exit the file earlier work is retained while the most recent change or mistake is eliminated To delete a modified Teletext Measurement limit file Touch the Delete soft key in the Teletext files directory The query line the top line of the display asks you to select a file to delete 2 Touch the soft key of the file you want to delete The VM 700T begins the deletion process The file is deleted when its soft key completely disappears from the screen NOTE Touch the Cancel soft key replaces the Delete soft key when deletion begins to halt the deletion process You can also halt file deletion by touching the file soft key 3 Touch the Leave Directory soft key to
23. et 2 8 Persistence 2 8 SoundInSync 2 15 Teletext 2 6 Waveform Display 2 8 Done soft key 1 7 E execute VM 700T Command 3 2 eye height 2 12 eye height description 2 4 eye measurement display 2 3 Eye Measurement Parameters Menu SoundInSync 2 16 Eye Measurement Parameters Submenu EyeHeight at Clock at XX 2 8 EyeHeight at Max 2 8 EyeWidth at Max 2 8 EyeWidth at Middle at XX 2 8 SoundInSync 2 15 Teletext 2 8 Threshold 2 8 Eye Measurement Submenu Acquire 2 6 Cursors 2 6 Display 2 6 Eye Meas Param 2 6 Rescale 2 6 Teletext 2 6 Timing Meas 2 6 Index 1 Index eye threshold 2 12 eye threshold description 2 4 eye width 2 12 eye width description 2 4 F filename specifying 1 6 files deleting 1 8 rules for naming 1 6 Source Selection Video 1 1 Teletext limit file creating 1 5 Teletext Measurements limit 1 1 Teletext Measurements limit changing 1 3 Video Limit changing 1 3 Video Source 1 1 Video Source changing 1 9 1 10 format of commands 3 2 Function Key Special Feature 2 1 3 6 G get VM700T Command 3 2 Get Set Keywords J Group Teletext Option Configuration NTSC 3 5 K Group Teletext Option Configuration PAL 3 5 getresults VM 700T Command 3 3 H hardkey VM 700T Command 3 3 Histogram Display 2 13 Histogram display 2 5 J jagged lines purpose of 2 1 K keyboard Setl 1 6 Set2 1 6 L Leave Directory
24. ey softkey name sneer ee nE e e e I 3 4 Get and Set Command Keywords iese SE SE eee eee ee 3 5 J Group Teletext Configuration NTSC EE SE SE see 3 5 K Group Teletext Configuration PAL ees Se ss ed see 3 5 Function Key Special Feature ses ES SS Se ee eee eee 3 6 Figure 1 1 The configure menu ss EE Se eee ene 1 2 Figure 1 2 Configure menus options 0 0 cece eee eee ese 1 2 Figure 1 3 Creating anew file 0 eee eee eee 1 3 Figure 1 4 Teletext NTSC System Default file 0 0 1 4 Figure 1 5 Teletext and SoundInSync PAL System Default file 1 5 Figure 1 6 File naming keyboard 00 0 0 eee eee eee eee 1 6 Figure 1 7 Channel Configuration System Default file 1 9 Figure 1 8 Source Selection Video file 0 00 0 0000 1 11 Figure 1 9 Teletext measurement results file llle esses 1 12 Figure 1 10 SoundInSync measurement results file luus 1 13 Figure 2 1 Measure Mode menu choices ES Se SE Se es ee 2 2 Figure 2 2 Teletext timing display ESE 0 0 0 0 cee eee ee eee 2 3 Figure 2 3 Teletext Eye display without histogram 2 4 Figure 2 4 Teletext Eye display with histogram 2 6 Figure 2 5 Teletext menu tree 2 8 Figure 2 6 Teletext Special Position display lesse 2 11 Figure 2 7 SoundInSync
25. faults supplied with the VM 700T you can configure the Teletext Measurement option according to your preferences To configure and use new parameters in Teletext measurements you must do the following tasks W Create your own Teletext Measurement limits file for example NewLimits and configure it with your limits W Create your own Video Source file for example NewSource and select NewLimits as the limits file to use m Configure the Source Selection Video file to select the NewSource file as a source file for one or all of the channels A B or C as needed for your measurements Use the following steps to create and configure new files 1 Press the Configure button to begin configuration of the Teletext Measure ment option The screen displays a memory use indicator information about instrument option versions and four soft keys touch screen buttons as shown in Figure 1 1 VM700T Option 20 Teletext Measurements User Manual 1 1 Configuring the Option Non volatile memory used 52416 bytes free 995904 bytes used 5 free 95 VM700T Video Measurement Set Xxxxxx Xxxx Option 01 NTSC Version 2 09 Option 11 PAL Version 2 09 Option 40 Audio Version 1 05 Option 30 Component Version 1 01 Option 20 Teletext Version 1 01 Option 1G Echo Rounding Version 1 00 Option 21 Camera Testing Version 1 02 Time Configure Function Option Files Keys Key Figure 1 1 Th
26. hoices into view If a default Teletext file is acceptable the VM 700T uses it if it is the selected file to measure input video signals You can modify the Teletext limits from the system defaults by creating a new measurement limit file to edit System Default NewLimits NTSC Files In nvramg ConfigFiles Teletext NTSC Switch Create Print Leave Delete Rename A NTSC PAL File File Directory Figure 1 3 Creating a new file VM700T Option 20 Teletext Measurements User Manual 1 3 Configuring the Option System Default Teletext Option Configuration Locations Field Line Teletext 1 15 Limits Lower Upper 1 Level 482 0 518 0 0 Level 18 0 18 0 Eye Height 5 70 0 100 0 Eye Height mV 350 0 500 0 Eye Width 4 70 0 100 0 P P Amplitude 5 100 0 130 0 P P Amplitude mV 500 0 650 0 Run In Start u sec 9 0 11 0 Run In Bits bits 14 0 18 0 Data Line Width u sec 52 0 59 0 Data End to Sync u sec 1 00 3 00 Run In Amplitude mV 482 0 518 0 Line 22 Showing rom ConfigFiles Teletext NTSC System Default No Change amp Exit Figure 1 4 Teletext NTSC System Default file 14 VM700T Option 20 Teletext Measurements User Manual Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com Configuring the Option System Default Teletext Option Config
27. hold Cursors brings up the Cursors submenu which provides soft keys to display and activate the cursors Acquire brings up the Acquire submenu which controls how the signal is acquired for the Teletext measurement Rescale sets the expansion factor of the display to an appropriate scaling factor for the Teletext measurement s display graticule The X and Y axes adjust to accommodate the rescaled display VM700T Option 20 Teletext Measurements User Manual 2 7 Operating Basics Main Menu Eye Timing Average Rescale Meas Ref 50 Num 32 Eye Measurement Submenu Timing Display EYeMeaS Cursors Acquire Rescale Meas Param Display Submenu Full Histogram Grading Waveform Persist Histogram Histogram at Clock Display Display 64 Wfms Reset Eye Measurement Parameters Submenu l EyeHeight EyeHeight EyeWidth EyeWidth Threshold At Clock At Max At Middle AtMax 1 250 Cursors Submenu Voltage Timing Cursor Set 100 Cursor 1 Cursor 2 Cursor On Cursor On Relative Active Active Acquire Submenu Special V Phase V Phase Clock F Position Only Only 444 Fh S
28. ile Name Source A NTSC System Default System Default Source B PAL System Default System Default Source C NTSC System Default System Default Timed Events System Default The softkey command soft key used as one word indicates the press and release of a specified soft key such as Cursors Sending the softkey command is equivalent to entering softpress and softrelease however you would generally use the softkey command instead Example VM700 softkey Select Graph With a few exceptions the general rule for forming a softkey name is to take the spelling and capitalization from the soft key name on the display omit the variable part and join the words with _ underscore For example the softkey name for the Noise 15 03 dB soft key is Noise dB and for 1H Display it is H Display For soft keys that perform toggle operations such as on off the softkey name is followed by a colon For example Plot ON or Freq LINEAR The soft key displays the current status of the toggle The convention for naming toggle keys is to use the function name with appropriate capitalization up to but not including the colon VM700T Option 20 Teletext Measurements User Manual Remote Commands and Keywords Get and Set Command Keywords J Group Teletext Configuration NTSC K Group Teletext Configuration PAL This section documents the Teletext measurement keywords used with the get and set commands For each get se
29. ints and brings up the Display submenu for selecting waveform persistence or choosing between a waveform or grading display Eye Meas Eye Meas Param brings up the Eye Measurement Parameters Param submenu which provides soft keys for setting such parameters as eye height eye width and threshold Cursors Cursors brings up the Cursors submenu which provides soft keys to display and activate the cursors Rescale Rescale sets the expansion factor of the display to an appropriate scaling factor for the SoundInSync measurement s display graticule The X and Y axes adjust to accommodate the rescaled display Main Menu Eye Meas Display Barn Cursors Rescale Display Submenu Full Histogram Grading Waveform Persist Histogram Histogram at Clock Display Display 64 Wfms Reset Eye Measurement Parameters Submenu EyeHeight EyeHeight EyeWidth EyeWidth Clock F Threshold At Clock AtMax AT Middle AtMax 382 Fh 1 250 Cursors Submenu Voltage Timing Cursor Set 100 Cursor 1 Cursor 2 CursorOn CursorOn Relative eed Active Active Figure 2 9 SoundinSync menu tree VM700T Option 20 Teletext Measurements User Manual 2 15 Operating Basics 2 16 Display Submenu Full Full Histogram displays a histogram of all timing points Histogram Histogram Histogram at Clock At XX displays a histogram at a at Clock specific timing point The position of the clock is default To change
30. ive highlighted the cursor delta is displayed as a percentage of a user definable voltage or timing distance When not high lighted the cursor delta is displayed in IREs or millivolts for voltage cursors and as a percentage of the clock period for timing cursors Set 100 Set 100 defines the current cursor delta as the reference position for cursor relative measurements Cursor 1 Cursor 1 Active displays voltage or timing cursors which Active ever is highlighted and causes the knob to move cursor 1 Cursor 2 Cursor 2 Active displays voltage or timing cursors which Active ever is highlighted and causes the knob to move cursor 2 Acquire Submenu Special Position V Phase Only V Phase Only Clock F 444 Fh 2 10 Special Position brings up the Special Position display Figure 2 6 and brings up the Special Position submenu which provides soft keys to set the measurement locations for the Teletext measurement V Phase Only PAL makes the measurement on only the V phase part of the signal V Phase Only PAL makes the measurement on only the V phase part of the signal Clock F specifies the multiple of the horizontal line frequency used for the Teletext measurement This value can be set to 444 or 397 by turning the knob when the soft key is highlighted The default is 444 VM700T Option 20 Teletext Measurements User Manual Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176
31. ld for NTSC and line number being measured The graphical display portion of the screen shows the waveforms of the digital data being transmitted Two clock cycles of digital data are plotted in each waveform on the display in pairwise sequential fashion that is the first waveform shows cycles 1 and 2 the second waveform shows cycles 2 and 3 the third shows cycles 3 and 4 and so on Clock edge positions are indicated by vertical lines at the left center and right of the x axis of the Eye Measurement display The mid point of each cycle is also indicated by smaller vertical lines on the same axis Two vertical arrows on the display show the time at which the eye height measurement is being made Similarly two horizontal arrows on the display show the level at which the eye width measurement is being made Teletext NTSC Wim gt Teletext Field 1 Line 17 Level mV 750 0 700 0 82920 Eye Threshold 1 250 600 0 Eye Height 56 7 550 0 261 9 mv 500 07 At Clock Eye Width 81 2 450 031 At Middle 400 0 350 0 1 Level 482 0 mv 300 0 0 Level 19 9 mv 250 0 P P Amp 133 7 617 8 mv 200 0 150 0 100 01 50 0 0 0 50 0 100 0 150 0 200 0 Persistence 32 Wfms Accumulation 330 times Figure 2 3 Teletext Eye display without histogram VM700T Option 20 Teletext Measurements User Manual Operating Basics Digital readouts on the Eye Measurement display give the values of the foll
32. les of the data contained in the Measurement Results files Measurement Results Channel A Fri Aug 30 16 19 59 Teletext Waveform gt Teletext Field 1 Line 15 Accumulation 400 times Timing Average Off Eye Threshold 1 250 Eye Height 45 9 70 0 100 0 28 1 IRE 49 0 70 0 At Clock Eye Width 58 1 70 0 100 0 At Middle 1 Level 66 0 IRE 67 5 72 5 0 Level 4 7 IRE 2 5 2 5 P P Amplitude 156 8 iy 100 0 130 0 96 1 IRE 70 0 91 0 Run In Start 9 91 u sec Run In Bits 16 0 bits Data Line Width 50 32 u sec i 52 00 59 00 Data End to Sync 3 32 u sec E 1 00 3 00 Run In Amplitude 52 7 IRE e 67 5 72 5 Figure 1 9 Teletext measurement results file VM700T Option 20 Teletext Measurements User Manual Configuring the Option Measurement Results Channel A Fri Aug 30 16 37 29 SoundInSync Line 96 SIS mode Accumulation 200 times Eye Threshold 1 250 Eye Height 86 2 201 0 mV At Clock Eye Width 77 5 At Middle 3 Level 370 8 mV 2 Level 147 1 mV 1 Level 86 1 mV 0 Level 310 9 mV P P Amplitude 106 0 722 5 mV Figure 1 10 SoundInSync measurement results file VM700T Option 20 Teletext Measurements User Manual 1 13 EUN Operating Basics The VM700T Video Measurement Set Teletext option measures parameters related to the transmission of digital information in the vertical interval This measurement requires a teletext signal Running the Teletext measurement writes a file ca
33. lled Teletext into the Measurement Results directory SoundInSync measures parameters related to the transmission of digital information in the sync pulse This measurement requires sound in the sync pulse to guarantee proper operation Running the SoundInSync Measurement writes a file called SoundInSync into the Measurement Results directory Function Key Special Feature A special feature enables Teletext and SoundInSync measurements on signals with offsets in the sync level such as found in scrambled video The procedure requires that the measurements be called from a Function Key Refer to Function Key Special Feature on page 3 6 for more information Measure Mode Menu Operation Measure mode is used for making interactive measurements of NTSC and PAL signal properties and accessing the measurements of any installed options as shown in Figure 2 1 This is different from Auto Mode which is used for automatic non interactive and continuous execution of user specified measure ments To view the Video Options directory window press the Measure button on the front panel If the VM 700T was in the Video Options directory when you last used Measure mode the Video Options directory displays Otherwise touch the Video Options soft key at the bottom of the display to view the Video Options directory Touch the Teletext soft key to display the measurement selections for the Teletext option VM700T Option 20 Teletext Measurements User Manual
34. mmer Manual VM700T Option 20 Teletext Measurements User Manual 3 1 Remote Commands and Keywords Command Format The VM700T remote control commands use this form command argument s The command is the actual command name Variable values are shown in italic Optional arguments are enclosed with A discussion of command usage and arguments follows the command header NOTE VM 700 is a prompt which you can change not an input Teletext measurement Remote Commands The following VM 700T remote commands can be used with the Teletext measurement option execute application The execute command starts the specified VM 700T application An application is one of the executable files with exceptions noted below found in the Instrument Operations VM 700 Diagnostics Video Measurements or Audio Measurements directories in the Executable Files directory Selecting an operational mode application such as Vector is equivalent to pressing the front panel button the LED on the selected button is turned on Selecting a measurement or diagnostic application is equivalent to touching the desired soft key Example VM700 execute SoundInSync You may run these Teletext measurement applications under remote control Be sure to use the same capitalization and tildes as shown Teletext SoundInSync get keyword The get command returns the configuration file value specified by keyword on channel letter the chan
35. n the Main menu brings up the Histogram display Figure 2 8 The left half of the Histogram display shows the same plot of signal level versus time as the left half of an Eye Measurement display In the Histogram display however the digital readouts of the Eye Measurement display are replaced by a histogram of the number of occurrences of waveforms at various signal levels All histograms are drawn with 2 55 mV resolution Sound In Sync Line 60 SIS mode Level mV 400 0 350 300 250 200 150 100 I u eo oo coc 9 CoO 9 FS eee Ss eS Fe Fs Ss Persistence 128 Wfms Accumulation 1640 times Full Grading V Persist Histogram Histogram Display 128 Wms Reset Figure 2 8 SoundInSync Histogram display When using the SoundInSync Eye Measurement it is important to have a significant number of clock cycles accumulated in order to ensure accuracy The number accumulated should be at least 200 and preferably 2 000 or more 2 14 VM700T Option 20 Teletext Measurements User Manual Operating Basics SoundinSync Menu Pressing the Menu button when the SoundInSync measurement is being executed brings up the SoundInSync main menu Figure 2 9 Main Menu Display Display shows the histogram at the clock point or at all po
36. nel specified by channel letter The keywords available are listed in the following section The channel letters available are A B or C Example VM700 get JOLV A The above example returns the 0 level in millivolts for channel A 3 2 VM7007T Option 20 Teletext Measurements User Manual Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com Remote Commands and Keywords getresults The getresults command stores Measure or Auto mode measurement results in default files in the Measurement Results directory In Measure mode entering getresults with no argument s stores the measurement results for the current measurement If no measurement is currently being executed the message Request not supported is returned If a measurement is being executed the message Results in file filename is returned Use the show filename command to view the results Example VM700 getresults Results in file Teletext hardkey button name The hardkey command hard key used as one word indicates the press and release of the specified front panel button button name Sending the hardkey command is equivalent to using hardpress and hardrelease however you would generally use the hardkey command instead Example VM700 hardkey Menu Front panel button names are listed in Table 3 1 Table 3 1 Button Names A Display Picture Auto Freeze SelectLine Average
37. nu structure is shown in Figure 2 5 Main Menu Eye Meas Timing Ref Average Num Rescale Eye Meas starts the Teletext eye measurement and brings up the Eye Measurement display and the Eye Measurement submenu Timing Ref allows you to select between 50 normal and 10 of the falling edge of the sync pulse as the timing reference for the run in sequence timing measurement Average Num specifies the weighting factor to be used for averaging The Average Num range is 1 to 256 The default value is 32 To change the Average Num value touch the Average Num soft key to highlight it rotate the knob until the desired weighting factor appears then press the Average Num soft key again Rescale sets the expansion factor of the display to an appropriate scaling factor for the Teletext measurement s display graticule The X and Y axes adjust to accommodate the rescaled display Eye Measurement Submenu Timing Meas Display Eye Meas Param Cursors Acquire Rescale Timing Meas starts the Timing Measurement and brings up the Timing Measurement display and Teletext main menu Display shows the histogram at the clock point or at all points and brings up the Display submenu for selecting waveform persistence or choosing between a waveform or grading display Eye Meas Param brings up the Eye Measurement Parameters submenu which provides soft keys for setting such parameters as eye height eye width and thres
38. orms accumulated for measure ment derivation and histogram display VM700T Option 20 Teletext Measurements User Manual 2 5 Operating Basics Teletext Histogram Display Pressing the Display soft key on the Eye Measurements menu brings up the Histogram display Figure 2 4 Teletext NTSC Wim gt Teletext Field 1 Line 17 Level mV 600 04 550 0 500 450 400 350 300 250 200 150 100 01 Io N e uU o 6 6 EE vo Nee NA 7 Persistence 32 Wfms Accumulation 952 times Histogram Grading Persist Histogram At clock Display 32 Wfms Reset Figure 2 4 Teletext Eye display with histogram The left half of the Histogram display shows the same plot of signal level versus time as the left half of an Eye Measurement display In the Histogram display however the digital readouts of the Eye Measurement display are replaced by a histogram of the number of occurrences of waveforms at various signal levels All histograms are drawn with 2 55 mV resolution When using the Teletext Eye Measurement display it is important to have a significant number of clock cycles accumulated in order to ensure accuracy The number accumulated should be at least 200 and preferably 2 000 or more 2 6 VM700T Option 20 Teletext Measurements User Manual Operating Basics Teletext Menu Pressing the Menu button when the Teletext measurement is being run displays the Teletext main menu The Teletext me
39. owing eye threshold indicates the proportion of data points being omitted from histogram displays at the extremes of variation in signal level for the eye measurement This value can be set with the Threshold soft key path Eye Meas Eye Meas Param Threshold eye height gives the eye height measurement as a percentage of the difference between the 0 and 1 levels The timing position at which the measurement is taken is also shown eye width gives the eye width measurement as a percentage of the clock cycle time The signal level at which the measurement is being taken is also shown level gives the nominal signal level for a digital 1 value 0 level gives the nominal signal level for a digital 0 value For PAL standard signals the unit of measurement for the readouts listed above is millivolts For NTSC standard signals the unit of measurement is IRE or millivolts Select the one you want in the Teletext file in the nvramO Config Files directory The default NTSC unit of measurement is IRE P P amplitude gives the maximum difference between high and low signal levels as a percentage of the difference between the 0 and 1 levels and in IREs NTSC or millivolts PAL Persistence indicates the number of most recent waveforms displayed on the graph This value can be set with the Persist soft key path Eye Meas Display Persist Accumulation indicates the number of wavef
40. pecial Position Submenu Set Run In Exit Defau 11 2 uSec Figure 2 5 Teletext menu tree Display Submenu Full Full Histogram displays a histogram of all timing points Histogram Histogram Histogram at Clock At XX displays a histogram at a at Clock specific timing point The position of the clock is default To 2 8 change the position of the timing point touch and hold the soft key and turn the knob The position of the timing point is given relative to the clock position as a percentage of the clock period VM700T Option 20 Teletext Measurements User Manual Operating Basics Grading Display Waveform Display Persistence Histogram Reset Grading Display shows accumulative waveform information Larger accumulations yield better results Waveform Display shows the most recent waveforms and brings up the Persistence soft key to select the number of waveforms displayed Persistence selects the number of waveforms to be shown in the Waveform display This value can be varied in powers of two from 4 to 1024 plus zero no persistence and infinite all waveforms displayed To change the Persistence value touch the soft key to highlight it then turn the knob Histogram Reset clears all accumulated waveforms and restarts the eye measurement Eye Measurement Parameters Submenu EyeHeight at Clock EyeHeight at Max EyeWidth at Middle EyeWidth at Max
41. plays at the extremes of variation in signal level for the eye measurement This value can be set with the Threshold soft key path Eye Meas Param Threshold eye height gives the eye height measurement as a percentage of the difference between the two signal levels being measured as well as in millivolts The timing position at which the measurement is being taken is also shown eye width gives the eye width measurement as a percentage of the clock cycle time The signal level at which the measurement is being taken is also shown 3 level gives the nominal signal level for a digital 3 value in millivolts 2 level gives the nominal signal level for a digital 2 value in millivolts level gives the nominal signal level for a digital 1 value in millivolts 0 level gives the nominal signal level for a digital 0 value in millivolts P P amplitude gives the maximum difference between high and low signal levels expressed both as a percentage of the difference between the 0 and 3 levels and in millivolts Persistence indicates the number of most recent waveforms displayed on the graph This value can be set with the Persist soft key path Display Persist Accumulation is the number of waveforms accumulated in the measurement and the Histogram display VM700T Option 20 Teletext Measurements User Manual 2 13 Operating Basics SoundinSync Histogram Display Pressing the Display soft key o
42. rements User Manual Configuring the Option Editing the Video To modify the Video Source file Source File 1 Touch the Create File soft key The guery line the top line of the display asks you to select the file to use as a template for your new file Touch the appropriate soft key for the file you want to use for example System Default A keyboard displays Type the name for your new file Touch the Done key The VM700T displays the contents of the new file that contains the Video Source data from the file you selected as the template You can modify parameters in this file Changing the Video To change the Video Source parameters Source Parameters 1 Rotate the knob to highlight the line that contains the parameter you want to change in this case highlight the line Teletext System Default Touch the desired parameter for example touch Teletext System Default A box highlights the selected parameter Rotate the knob to change the parameter or value select the name of the new Video Source file Touch the Accept Input soft key to accept the change The highlight box disappears and the new parameter displays Touch the Update amp Exit soft key to save the change and return to the Video Source Files menu NOTE If you change a parameter and don t want to save the change touch the No Change amp Exit soft key The VM 700T asks you to touch the No Change amp Exit soft key again to verify tha
43. s for voltage cursors and as a percentage of the clock period for timing cursors Set 100 Set 100 defines the current cursor delta as the reference position for cursor relative measurements Cursor 1 Cursor 1 Active displays voltage or timing cursors which Active ever is highlighted and causes the knob to move cursor 1 Cursor 2 Cursor 2 Active displays voltage or timing cursors which Active ever is highlighted and causes the knob to move cursor 2 VM700T Option 20 Teletext Measurements User Manual 2 17 RA Remote Commands and Keywords Like other VM700T Video Measurement Set video functions remote control of Teletext and SoundInSync measurement functions is performed through the serial RS 232C or parallel GPIB option 48 ports on the VM 700T rear panel Using the remote control functions requires that you connect a terminal or computer to the VM 700T through the RS 232C port with a correctly wired interconnect cable If you use a computer you will also need a suitable VM 700T terminal program such as the Tektronix application VMT for serial communica tion VMT offers a choice of either menu selection or command line entry of VM700T remote commands For GPIB communications you will need a GPIB controller and appropriate controller programming Connection between the GPIB controller and the VM 700T is through a standard GPIB interface cable For information about configuring the VM 700T serial ports for remote opera tion se
44. s numbers and the following punctuation characters _ underline dot minus sign plus sign colon and tilde in names Avoid using punctuation characters other than those mentioned above in a directory or file name m Multi line directories and file names can be entered using the Return key Touch Return on the touch screen keyboard to get to the second line m When the VM700T is in remote mode the return character becomes a tilde character for purposes of file name reference Thus a directory whose name is displayed as JOHN SMITH in the directory display becomes JOHN SMITH when referred to in a remote operation 5 Touch the Done soft key when you have named the file The VM 700T displays the new file containing the Teletext Measurement limits from the file you selected as the template You can edit the parameters in this file Press Cancel instead of pressing Done if you do not want to create the new file Editing a Teletext To change any Teletext Measurement limit text parameter Measurement Limit Text Parameter In the editable file rotate the knob to highlight the line that contains the parameter you want to change This includes the title line in the configura tion file Use a descriptive title to easily identify it later This does not change the name of the file 2 Touch the parameter you want to change A box highlights the parameter 3 Rotate the knob to increase or decr
45. s the waveforms of the digital data being transmitted Two clock cycles of digital data are plotted in each waveform on the display in pairwise sequential fashion i e the first waveform shows cycles 1 and 2 the second waveform shows cycles 2 and 3 the third shows cycles 3 and 4 etc The vertical axis of the display is divided into four sections corresponding to a digital 0 1 2 and 3 respectively Clock edge positions are indicated by vertical lines at the left center and right of the x axis of the Eye Measurement display The mid point of each cycle is also indicated by smaller vertical lines on the same axis VM700T Option 20 Teletext Measurements User Manual Operating Basics Two vertical arrows on the display show the time along the horizontal axis and the signal level along the vertical axis at which the eye height measurement is being made To change the signal level whose eye height is being measured touch the screen anywhere between the signal levels you want to measure For example to measure eye height between the 2 and 3 signal levels touch the screen anywhere in that region Two horizontal arrows on the display show the times beginning and end at which the eye width measurement is being made Digital readouts on the Eye Measurement display give the values of the following parameters eye threshold indicates the proportion of data points being omitted from histogram dis
46. t keyword it gives the syntax of the set command and the get result and a description of what the keyword does For information on working with VM 700T remote control commands see the VM 700T RS 232 Interface Programmer Manual J Group keywords shown in Table 3 2 report on or set the values of Teletext Option Configuration parameters These keywords can only be used on NTSC standard VM 700 instruments equipped with Option 20 Teletext Get commands used with the J group keywords have the following form get keyword lt channel letter gt Set commands used with J group keywords take different arguments depending on the keyword Table 3 2 J Group Keywords Teletext Configuration NTSC Description P P Amplitude mV Keyword Keyword Description 0 Level mV J1LV 1 Level mV P P Amplitude 96 J DES Data End to Sync usec Run In Amplitude mV JDLW Data Line Width usec Run In Bits bits J EHM Eye Height mV J RIS Run In Start usec J EHP Eye Height JTTL Teletext field and line JEWP Eye Width JTUN Timing Unit K group keywords shown in Table 3 3 report on or set the values of Teletext Option Configuration parameters These keywords can only be used on PAL standard VM 700 instruments equipped with Option 20 Teletext Get commands used with the K keywords have the following form get keyword lt channel letter gt Set commands used with K group
47. t you want to exit without changing anything For more information about the other selections in the Video Source file see the user manual for your NTSC PAL or dual standard VM 700T Video Measure ment Set 1 10 VM700T Option 20 Teletext Measurements User Manual Configuring the Option Configuring the Source Selection Video Files Specifying a Video Source File The source channel A B or C for the video signal is configured in the Source Channel Selection file to accept NTSC or PAL sources as appropriate for the application see Figure 1 8 If you have created a new Video Source File you can edit the Video Source File Name parameter in this file to select it If you have a single standard instrument Option 01 NTSC or Option 11 PAL only the Video Source File Name column shows only the video standard installed You can select a Video Source file from the Source Selection Video if you intend to use a source file other than the system default for each of three sources Video NTSC Video Source File Name PAL Video Source File Name Std Source A NTSC System Default System Default Source B PAL System Default System Default Source C NTSC System Default System Default Timed Events System Default Line 8 Editing nvram0 ConfigFiles Source Selection Video Accept Input Figure 1 8 Source Selection Video file To specify a Video Source file Rotate the front panel knob until Source
48. uration Locations Teletext Line 17 Limits Lower Upper 1 Level 420 0 504 0 0 Level 14 0 14 0 Eye Height 5 70 0 100 0 Eye Height mV 323 0 562 0 Eye Width 4 70 0 100 0 P P Amplitude 5 100 0 130 0 P P Amplitude mV 462 0 600 0 Data Timing u sec 11 0 13 0 Run In Start u sec 9 0 11 0 Run In Bits bits 14 0 18 0 Data Line Width u sec 52 0 59 0 Data End to Sync u sec 1 00 3 00 Run In Amplitude mV 420 0 504 0 Sound In Sync 3 Level mV 370 0 430 0 2 Level mV 137 0 197 0 1 Level mV 97 0 37 0 0 Level mV 330 0 220 0 Eye Height 5 70 0 100 0 Eye Height mV 163 0 230 0 Eye Width 4 70 0 100 0 P P Amplitude 100 0 130 0 P P Amplitude mV 700 0 910 0 Line 36 Showing rom ConfigFiles Teletext PAL System Default No Change amp Exit Figure 1 5 Teletext and SoundInSync PAL System Default file Complete the following tasks to modify Teletext Measurement limit file parameters Create a Teletext The system default files cannot be altered If you wish to alter the default Measurement Limits File parameters you must set up new files that can be edited for your measurement requirements 1 Touch the Create File soft key see Figure 1 3 The query line the top line of the display then asks you to select a file template for your new file VM700T Option 20 Teletext Measurements User Manual 1 5 Configuring the Option 2 Touch the soft key of the file you
49. want to use for a template for example System Default 3 A keyboard displays as shown in Figure 1 6 4 Type the new file name observing the following rules and noting the special uses of some characters and keys W Spaces are not allowed in file or directory names usean underline or dot to separate words in a name m Forward slash and reverse slash Y are not permitted in the file name m When neither Set 1nor Set is highlighted you can type lowercase and uppercase English alphabet characters The lowercase Set1 character set allows you to enter numerals and punctuation characters The uppercase Set1 and the Set2 character set allow you to enter various special characters and accented characters for use in non English language file names Both the Set1 and Set2 character keys and the Shift soft key lock when selected Set1 and Set are unlocked by touching the same key again or touching the unselected key of the pair Shift is unlocked by touching Shift again m A maximum of 31 characters are allowed in a file or directory name Please enter file name max 31 characters NewLimi t ERE ERA ER LEA ERES EI AGS Back EJ ES EE LIG DE JOJCJCJ CJ CJCJ EF sett Cancel set2 Space shift Figure 1 6 File naming keyboard 1 6 VM700T Option 20 Teletext Measurements User Manual Configuring the Option m Use only uppercase and lowercase letter

User Manual VM700T Video Measurement Set Option 20 Teletext

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