User Manual VM700T Video Measurement Set Option 22 Video
Contents
1. Wander_Source System Default In nvram0 ConfigFiles Video_Source Files NTSC NTSC Files Delete Switch Create Rename Print Leave NTSC PAL File File Directory Figure 4 Typical Video Source file display h Touch the Done soft key when you have finished naming the file If you do not want to create the new file touch the Cancel key to quit the process After you touch the Done soft key the measurement set displays the contents of the new Wander measurement video source file the source data from the template file you selected You can now modify the video source file as described in step 2 2 Modify your Wander measurement video source file NOTE You can view the parameters in any video source file However to modify the parameters of the System Default file you must create a copy of the System Default file and edit the copy a If you just completed step 1 and the measurement set is displaying your new Wander video source file proceed to step 2c Open the Wander measurement video source file you want to edit To locate your existing Wander measurement video source file s first press the front panel Configure button to enable the measurement set Configuration mode See Figure 1 Touch the Configure Files soft key then use the front panel knob to scroll through the window to locate the Video_Source Files soft key VM700T Option 22 Video Wand2. 0 1 Hz for PAL may be reprogrammed to any value Normalization The internal frequency reference of the measurement set drifts over time which can affect the Frequency Offset measurement accuracy To maintain measurement accuracy periodically normalize the measurement set to a stable frequency reference to zero out any drift that has accumulated over time Normalization is performed by using the Zero Offset function while measuring a reference video signal Since the measurement accuracy is based on the accuracy of the reference signal use a reference signal with stability drift typically better than 100 ppb hr A suggested reference signal is a black burst signal from a Tektronix SPG422 Component Digital Master Sync Generator You can lock the SPG422 generator to an Rb or Ce clock source for optimum accuracy If the VM700T Video Measurement Set is in a stable temperature environment normalization should be done every half hour To maintain optimum measure ment accuracy periodically normalize the measurement set at intervals of less than half an hour VM700T Option 22 Video Wander Measurements User Manual Operating Basics Performing the Perform the following procedure to measure the amount of frequency offset in Measurement your composite video signal NOTE To maintain optimum measurement accuracy periodically normalize the measurement set at intervals of less than half an hour Refer to Normalization on page 12 1
3. Lower 9999 0 Factory default value 226 0 Creating and Editing a Video Source File Video Source file Perform the following procedure to create a new Video Source file and to edit a 1 Create a new Wander measurement video source file You only need to create a new video source file if you do not already have a user created video source file or you want to create a new video source file a Configuration mode See Figure 1 soft key options in a w indow Press the front panel Configure button to enable the measurement set Touch the Configure Files soft key The screen now displays a series of c Use the front panel knob to scroll through the window to locate the Video_Source Files soft key Touch the Video_Source Files soft key to enter the Video Source Files directory The screen displays the System Default file and any user created files that have been created See Figure 4 e Touch the Create File soft key The query line the top line of the display asks you to select a file to use as a template for your new file f Touch the soft key of the file that you want to use as a template for example System Default The screen displays a keyboard that you can use to type a name for your new file See Figure 3 rules and notes given on page 4 VM700T Option 22 Video Wander Measurements User Manual Type the new file name for example Wander_Source observing the Getting Started
4. Normalize the Frequency Offset application of the measurement set a Connect a composite video reference signal to a channel input of the VM 700T Video Measurement Set Press the Measure button on the front panel and then touch the Video Options soft key on the display Touch the Wander soft key to enable the Option 22 applications Press the front panel Menu button to display the application soft keys Use the Frequency Offset application to measure the video reference source on the channel input Use front panel Source buttons to select the input channel connected to the reference signal This is only necessary if you have more than one signal connected to the measurement set Touch the Zero Offset soft key to normalize the measurement set to the video reference signal 2 Measure the frequency offset of the video signal you want to test Figure 6 illustrates the Frequency Offset measurement display a Connect the composite video signal that you want to test to a channel input of the VM700T Video Measurement Set Press the Measure button on the front panel and then touch the Video Options soft key on the display Touch the Wander soft key to enable the Option 22 Video Wander measurements Touch the Frequency Offset soft key if necessary to display Frequency Offset application window Press the front panel Menu button to display the application soft keys Use the application soft keys to perform the measuremen
5. appropriate controller programming to the measurement set parallel connector For information about configuring the measurement set serial ports for remote operation and typical cable wiring configurations refer to the VM700T RS 232 Interface Programmer Manual For information about using the GPIB Option 48 parallel port refer to the VM700T Option 48 GPIB Interface Programmer Manual VM700T Option 22 Video Wander Measurements User Manual B 1 Appendix B Remote Control Remote Commands and Keywords N Group Keywords NTSC Only The VM700T Video Measurement Set remote commands use this form command argument s Variable values in the command are shown in italics Optional arguments are enclosed with A description of command usage and arguments follows the command header NOTE In the following descriptions VM700T gt is a prompt which you can edit not a required input N group keywords are for NTSC only Option 22 Video Wander measurements The keywords report on or set the values of the Drift Rate and Frequency Offset application configuration parameters The Get commands used with the N keywords have this form get lt keyword gt lt channel letter gt Shown below is an example of the commands required to change the Drift Rate limit values for NTSC VM700T gt get NDRT A 5 00 5 00 VM700T gt set NDRT A 20 20 VM700T gt get NDRT 20 20 VM700T gt NDRT and NFRO are the avai
6. for performing each of the video wander measurements and a description of the menu selections within each measurement window display Since video signal paths are usually self synchronized by phase tracking the input video signal it is not advantageous to limit the very low frequency spectral components to a fixed peak value Therefore the measurement set processes these slow phase variations in terms of Frequency Offset and Drift Rate which are more directly related to a video systems phase tracking ability The plot of the time error versus frequency accommodation in Figure 5 illustrates the effect of the LP Corner menu selections of 0 2 Hz 0 5 Hz and 1 0 Hz These LP Corner drift rate bandwidth values select the upper frequency limit of the Drift Rate measurement For example if a 10 ns peak jitter is considered acceptable it is not advantageous to restrict the peak drift rate to 28 ppb s above 0 2 Hz since as long as the peak jitter is below 10 ns the drift rate value is of no concern and can have any value lus p gt 28 ppb s drift rate 100 ns lt 28 ppb s drift rate 10 ns peak jitter floor 10 ns 2 5 ns peak jitter floor 1 0 k jitter fl ele ns peak jitter floor 0 2 Hz 05Hz 0 1 Hz 1 Hz 10 Hz Wander Region Jitter Region Figure 5 Plot of time error versus frequency accommodation VM700T Option 22 Video Wander Measurements User Manual 11 Operating Basics To better under
7. no special test signals measures standard composite video signals and provides the following two measurement methods for verification of video horizontal sync frequency m Frequency Offset measures the absolute horizontal sync frequency error m Drift Rate measures the rate of horizontal sync timing changes VM700T Option 22 Video Wander Measurements User Manual 1 Getting Started Configuration Creating and Editing a Configuration File NOTE Configuration of Option 22 is only necessary if you need to change the value of the displayed default limit markers There are no special test signals or measurement locations required to operate Option 22 Configuring the Option 22 Video Wander Measurements option is similar to configuring the other video functions of the VM700T Video Measurement Set When you install Option 22 a default measurement limits file and wander directory are provided which contain the parameters that the measurement set uses to perform the wander measurements If the parameters provided in the System Default file are acceptable you do not need to change the configuration files If your specific measurement application requires parameters other than the default parameters supplied with Option 22 you can reconfigure the configuration files to suit your testing requirements To reconfigure and use new measurement parameters for Option 22 you must perform these tasks m Create your own Wander configurati
8. the Done soft key when you finish naming the file If you do not want to create the new file touch the Cancel key to quit the process After you touch the Done soft key the measurement set displays the contents of the new Wander measurement configuration file the configuration data from the template file you selected You can now modify the parameters in the configuration file as described in step 2 2 Modify your Wander measurement configuration file NOTE You can view the parameters in any configuration file However to modify the parameters of the System Default file you must create a copy of the System Default file and then edit the copy Refer to the previous step for instructions a If you just completed step 1 and the measurement set is displaying your new Wander configuration file proceed to step 2c b Open the Wander measurement configuration file you want to edit To locate your existing Wander measurement configuration file s first press the front panel Configure button to enable the measurement set Configuration mode See Figure 1 Touch the Configure Files soft key then use the front panel knob to scroll through the window to locate the Wander soft key Touch the Wander soft key to display the Wander measurement System Default configuration file and any other Wander measurement configuration files that have been created See Figure 2 Touch the soft key of the configuration file you want to edit VM70
9. 0T Option 22 Video Wander Measurements User Manual 5 Getting Started c Select the parameter you want to change by rotating the front panel knob to highlight the line on the display containing the parameter and then touch the parameter This includes the title line in the configuration file Table 1 shows the editable fields in a user created Wander measurements limit file d Rotate the front panel knob to increase or decrease the value of the selected parameter e Touch the Accept Input soft key to accept the change NOTE If you change a parameter and then decide that you do not want to keep the change touch the No Change Exit soft key The measurement set verifies that you want to exit without changing anything by asking you to touch the No Change amp Exit soft key again To return to the file you created touch the soft key on the display the file you created now appears there Ifyou are making extensive changes to the file you can avoid losing all your changes by pressing the Update Exit soft key after each change and then re entering the file That way if you make a mistake and must exit the file your earlier work is retained while the most recent change or mistake is eliminated f Touch the Update amp Exit soft key and then touch Leave Directory to return to the main level of the Configuration mode See Figure 2 3 Perform this step only if you need to delete an existing configuration file
10. Test Equipment Depot User Manual 1 800 517 8431 Tektronix ys VM700T Video Measurement Set Option 22 Video Wander Measurements 071 0038 00 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com AAA A Table of Contents Getting Started soci inci cle ici a ai e 1 Product Description irere ae cette eee teenies 1 Configuration ing bce ee ab a gue ah tee ala paa ene 2 Operating Basics ssc o 3d eres sae ais aaa ness HHS eg See 11 Measurement Theory 4 vices Scns he Dik stale like BUDS Be Sata Sa 11 Frequency Offset Measurement 0 00 e rr 12 Drift Rate Measurement a aE e cece ee eee tenes 15 Appendix A Specifications 0 cece cece cere rece enone A 1 Option 22 Specifications 00 eect ete eens A 1 Appendix B Remote Control 0 cece cece cere eee eeee B 1 Remote Control Setup e eeina ee i e eee e ene n eee B 1 Remote Commands and Keywords 0 0 0 cece eee eee eee eee B 2 TAO aed se coca aa a a a aaa Index 1 VM700T Option 22 Video Wander Measurements User Manual i Getting Started Product Description This section provides a product description and instructions for configuring Option 22 Option 22 is a VM700T Video Measurement Set application designed to measure the horizontal sync timing wander characteristics also referred to as frequency offset and drift of a video signal that has been transport
11. a In the Wander measurement configuration files directory touch the Delete soft key See Figure 2 The query line the top line of the display asks you to select a file to be deleted NOTE You can halt file deletion by pressing the Cancel soft key in the same position as the Delete soft key before the deletion process started You can also halt file deletion by touching the screen image of the file A file is not deleted when you halt the deletion process b Select the file to be deleted by touching its soft key The measurement set begins the deletion process VM700T Option 22 Video Wander Measurements User Manual Getting Started Table 1 Editable fields in the Wander measurement configuration file Editable Item Choices Wander Option Configuration Name of file identification line can be changed for the defaults measurement reports This does not change the file name NTSC Limits Select any value between the upper and lower limits Drift Rate peak ppb s Upper 999 0 Factory default value 28 0 Lower 999 0 Factory default value 28 0 Frequency Offset peak ppb Upper 99990 0 Factory default value 2800 0 Lower 99990 0 Factory default value 2800 0 PAL Limits Select any value between the upper and lower limits Drift Rate peak ppb s Upper 999 0 Factory default value 22 6 Lower 999 0 Factory default value 22 6 Frequency Offset peak ppb Upper 9999 0 Factory default value 226 0
12. ecify a Video Source file perform the following procedure 1 Press the front panel Configure button to enable the measurement set Configuration mode See Figure 1 2 Touch the Configure Files soft key The screen now displays a series of soft key options in a window 3 Use the front panel knob to scroll through the window to locate the Source_Selection Video soft key 4 Touch the Source_Selection Video soft key 5 Rotate the front panel knob to highlight the source for which you are specifying a video source file source A B or C 6 Touch the highlighted source file to select it 7 Rotate the front panel knob to change the Video Source file selection 8 When you have selected a Video Source file touch the Accept Input soft key 9 If the change is correct touch the Update amp Exit soft key If the change is not correct touch the No Change amp Exit soft key and attempt the change again NOTE If you change the video source file and then decide to exit the directory and cancel the change press the Accept Input soft key followed by the No Change amp Exit soft key The measurement set verifies that you want to exit the Source Selection Video directory and cancel any changes by asking you to touch the No Change amp Exit soft key again VM700T Option 22 Video Wander Measurements User Manual AA SA Operating Basics Measurement Theory This section contains a measurement theory discussion instructions
13. ed over a SONET or SDH digital distribution network Sync timing wander is a common problem with contribution quality video that has been transported over SONET or SDH distribution networks Since sync timing wander is often misunderstood the problem is frequently undiag nosed Contribution quality video transport requires a higher level of network timing control than does voice or data transport Option 22 provides a simple and efficient method for the verification of horizontal sync frequency timing stability for contribution quality video applications Digital distribution networks which are synchronized to an external timing source buffer their data and use pointers to indicate the start of the next part of the payload At each step where data is multiplexed the network may add or drop a few bytes of buffered data pointer adjustments in order to maintain the average payload bit rate However pointer adjustments cause a phase variation in the network A portion if not all of this phase variation horizontal sync wander is trans ferred to the video signal that is recovered at the output of the Codec If this happens a composite video signal can exhibit subtle shifts in color hue or variations in sync phase when viewed on a waveform or vector monitor Excessive pointer adjustments in the network can cause levels of video wander to accumulate producing more severe problems including loss of synchronizing lock up Option 22 requires
14. er Measurements User Manual Getting Started Touch the Video_Source Files soft key to display the Wander measurement System Default video source file and any other Wander measurement video source files that have been created See Figure 4 Touch the soft key of the video source file you want to edit c Select the parameter you want to change by rotating the front panel knob to highlight the line on the display containing the parameter and then touch the parameter d Rotate the front panel knob to select the name of the new Wander_Lim its configuration file you created e Touch the Accept Input soft key to accept the change NOTE If you change a parameter and then decide that you do not want to keep the change touch the No Change Exit soft key The measurement set verifies that you want to exit without changing anything by asking you to touch the No Change amp Exit soft key again To return to the file you created touch the soft key on the display the file you created now appears there If you are making extensive changes to the file you can avoid losing all your changes by pressing the Update amp Exit soft key after each change and then re entering the file That way if you make a mistake and must exit the file your earlier work is retained while the most recent change or mistake is eliminated f Touch the Update Exit soft key and then touch Leave Directory to return to the main level of the Conf
15. ersion 2 10 Option 11 PAL Version 2 10 Option 40 Audio Version 1 05 Option 30 Component Version 1 01 01 Option 20 Teletext Version 1 01 01 Option 1G Echo Rounding Version 1 00 01 Option 21 Camera Testing Version 1 02 01 Option 22 Wander Version 1 00 Configure Function Option Time 2 Files Keys Key Figure 1 Typical Configure menu System Default NTSC files In nvram0 ConfigFiles Wander_Limits NTSC Delete Switch Create Rename Print Leave NTSC PAL File File Directory Figure 2 Typical configuration file display e Touch the Create File soft key The query line the top line of the display asks you to select a file to use as a template for your new file VM 700T Option 22 Video Wander Measurements User Manual Getting Started Touch the soft key of the file you want to use as a template for example System Default The screen displays a keyboard that you can use to type a name for your new file See Figure 3 Type the new file name for example Wander_Limits observing the following rules and noting the special uses of some characters and keys Spaces are not allowed in file or directory names use an under line _ or dot character to separate words in a name Forward slash and reverse slash Y characters are not permitted in the file name When neither Setl nor Set2 is highlighted you can type lowercase and uppercase English alphabet characters The lowercase Set1 characte
16. iguration mode See Figure 2 3 Perform this step only if you need to delete an existing video source file a Inthe Video_Source Files directory touch the Delete soft key See Figure 4 The query line the top line of the display asks you to select a file to be deleted NOTE You can halt file deletion by pressing the Cancel soft key in the same position as the Delete soft key before the deletion process started You can also halt file deletion by touching the screen image of the file Nothing happens to a file whose deletion process is halted b Select the file to be deleted by touching its soft key The measurement set begins the deletion process For more information about the other selections in the Video Source file refer to the VM700T Option 01 NTSC amp Option 11 PAL User Manual VM700T Option 22 Video Wander Measurements User Manual 9 Getting Started Configuring the Video Source Selection 10 The configuration files used by the measurement set for video wander measurements are configured in the Wander configuration directory and specified in the Video Source Files directory Likewise the video source files are configured in the Video Source Files directory and specified in the Source Selection Video directory In the Source Selection Video file you can select a source file if you want to use a video source file other than the System Default file for each of the three channel input sources To sp
17. ired to operate the Option 22 functions via remote control Option 22 can be controlled remotely either through the standard RS 232C interface or through the optional GPIB remote interface Control of the Op tion 22 application involves sending the appropriate softkey softpress or softrelease command followed by the desired soft key name in the application Like other VM700T Video Measurement Set functions remote control of the Video Wander measurements is performed via the serial RS 232C or parallel GPIB Option 48 ports on the measurement set rear panel Capabilities available while operating the measurement set from a remote location include m Make a specific manual measurement or an Auto mode series of measure ments m Execute and interrupt a function Function Key m Temporarily change the configuration of a channel To use the RS 232C remote control functions you must connect a terminal or computer to the measurement set RS 232C serial port If you use a computer you must also have a suitable terminal program to operate the measurement set Tektronix offers a software package called VMT Remote Control Software for serial communication This software package provides a choice of using either menu selection or command line entry of VM700T Video Measurement Set remote commands To use the GPIB remote control functions you must have Option 48 GPIB installed in your measurement set You will then connect a GPIB controller with
18. lable keywords for the N group NDRT NDRT specifies the lower and upper limits in ppb s for the NTSC Drift Rate measurement The set command takes two arguments after the channel letter representing the values of the lower and upper limits respectively Valid values for the limit numbers are between 999 0 and 999 0 ppb s NFRO NERO specifies the lower and upper limits in ppb for the NTSC Frequency Offset measurement The set command takes two arguments after the channel letter representing the values of the lower and upper limits respectively Valid values for the limit numbers are between 99990 0 and 99990 0 ppb VM700T Option 22 Video Wander Measurements User Manual Appendix B Remote Control 0 Group Keywords PAL Only O group keywords are for PAL only Option 22 Video Wander measurements The keywords report on or set the values of the Drift Rate and Frequency Offset application configuration parameters The Get commands used with the O keywords have this form get lt keyword gt lt channel letter gt Shown below is an example of the commands required to change the Drift Rate limit values for PAL VM700T gt get ODRT A 5 00 5 00 VM700T gt set ODRT A 20 20 VM700T gt get ODRT 20 20 VM700T gt ODRT and OFRO are the available keywords for the O group ODRT ODRT specifies the lower and upper limits in ppb s for the PAL Drift Rate measurement The set command takes two argumen
19. n Hz Use this soft key to select the measurement bandwidth 1 Hz 1 ns maximum peak jitter studio quality 0 5 Hz 2 5 ns maximum peak jitter contribution quality 0 2 Hz 10 ns maximum peak jitter distribution quality Rescale Touch this soft key to automatically rescale the display for optimum viewing Peak Hold Touch this soft key to detect and hold the peak timing variations over the prior 17 seconds 16 VM700T Option 22 Video Wander Measurements User Manual Appendix A Specifications Table A 1 lists the specifications for the VM700T Video Measurement Set Option 22 All specifications listed here are guaranteed unless labeled typical in the Characteristics column Typical specifications are provided for your convenience but are not guaranteed Option 22 Specifications Table A 1 Option 22 specifications Characteristics Frequency Offset measurement Measurement range Measurement accuracy Stability drift typical Drift Rate measurement Measurement range Measurement accuracy VM700T Option 22 Video Wander Measurements User Manual Description 90 ppMp p Accuracy determined by reference source lt 100 ppb hr 90 ppm Sp p Resolution and accuracy better than 10 ppb s A er Appendix B Remote Control Remote Control Setup More Information This section contains general information on how to connect the VM700T Video Measurement Set for remote control and the specific remote commands and keywords requ
20. on file for example Wander_Limits and configure it with your own parameter values m Create your own Video Source file for example Wander_Source and select the Wander_Limits file as the limits file to be used m Configure the Source_Selection Video file to select the Wander_Source file as a source file for one or all of the channels A B or C as needed for your measurements Perform the following procedure to create a new Wander configuration file and to edit a configuration file 1 Create a new Wander measurement configuration file You only need to create a new configuration file if you do not already have a user created configuration file or you want to create a new configuration file a Press the front panel Configure button to enable the measurement set Configuration mode See Figure 1 b Touch the Configure Files soft key The screen now displays a series of soft key options in a window c Use the front panel knob to scroll through the window to locate the Wander configuration file soft key d Touch the Wander soft key The screen displays the System Default file and any user created files that have been created See Figure 2 VM700T Option 22 Video Wander Measurements User Manual Getting Started Non volatile memory used 52416 bytes free 995904 bytes used free 5 95 VM700T Video Measurement Set XXXXXX XXXX Option 01 NTSC V
21. post processing equipment Therefore measuring the drift rate is of primary concern for users of such equipment Drift rate limit markers of 0 028 ppm s for NTSC and 0 0226 ppm s for PAL are marked and can be reprogrammed to any value you desire Display limit markers indicate the drift rate peaks in ppm s and Hz s Fsc over the past 17 seconds Performing the Figure 7 illustrates the Drift Rate measurement display Perform the following Measurement procedure to measure the drift rate of your composite video signal 1 Connect a composite video signal to a channel input of the VM700T Video Measurement Set 2 Press the Measure button on the front panel and then touch the Video Op tions soft key on the display 3 Touch the Wander soft key to enable the Option 22 applications 4 Press the front panel Menu button to display the application soft keys 5 Touch the Drift Rate soft key if necessary to display Frequency Offset application display 6 Use the soft keys listed below to perform the measurement you need VM700T Option 22 Video Wander Measurements User Manual 15 Operating Basics Drift Rate NTSC Peak 2 17 ppm sec ppm sec Peak 7 76 Hz sec Fsc Figure 7 Drift Rate measurement display Drift Rate Soft Keys Drift Rate Touch this soft key to toggle to the Drift Rate application display Frequency Offset Touch this soft key to toggle to the Frequency Offset applica tion display LP Corner
22. r set allows you to enter numerals and punctuation charac ters The uppercase Setl and the Set2 character set allow you to enter various special or accented characters for use in nonEnglish language file names The Set1 Set2 and Shift soft keys lock when they are selected Setl and Set2 are unlocked by touching the same key again or touching the unselected key of the pair Shift is unlocked by touching Shift again A maximum of 31 characters are allowed in a file or directory name Please enter file name max 31 characters NewLimi tsi JAG Ge Cancel Figure 3 File naming keyboard sett set Space EN VM700T Option 22 Video Wander Measurements User Manual Getting Started m Use only uppercase and lowercase letters numbers and the following punctuation characters in names _ underline dot 2 minus sign plus sign colon and tilde Avoid using punctuation characters other than those mentioned above in a directory or file name m Multiline 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 Video Measurement Set is in Remote mode the return character becomes a tilde character for purposes of file name reference Thus a directory name that is displayed as JOHN SMITH becomes JOHN SMITH in a remote operation h Touch
23. stand this concept consider the typical contribution quality video signal These signals typically have broad band jitter and wander that is composed of many spectral components but may have large low frequency jitter or wander due to digital buffering and reclocking Contribution quality video is not well defined but a jitter limit of 2 5 ns peak since no other limit currently exists and a drift rate limit of 28 ppb s would be only slightly worse than a studio black burst reference signal such as SMPTE RP 154 1994 Therefore it is advantageous to only measure the jitter spectral components below 0 5 Hz in terms of drift rate and measure jitter above 0 5 Hz in terms of its peak or peak to peak time value For final distribution quality video 10 ns peak jitter may be acceptable In this case the drift rate should only be measured below 0 2 Hz The general concept is that large acceptable jitter floors imply using a low LP Corner value Frequency Offset Measurement 12 Frequency Offset is a frequency accuracy measurement of the absolute frequency error of a video signal as compared to a reference video signal When the measurement set is warmed up you can make accurate measurements of the input video signal frequency to within 100 ppb of the reference signal frequency Display limit markers indicate peak frequency offset in ppm and Hz Fsc over the past 17 seconds Default limit markers of 2 8 ppm 10 Hz for NTSC and 0 226 ppm
24. t you need VM700T Option 22 Video Wander Measurements User Manual 13 Operating Basics Frequency Offset NTSC 2 47 ppm 5 83 Hz Fsc Peak Hold Figure 6 Frequency Offset measurement display Frequency Offset Drift Rate Touch this soft key to toggle to the Drift Rate application display Soft Keys Frequency Offset Touch this soft key to toggle to the Frequency Offset applica tion display Zero Offset Touch this soft key to zero the frequency offset measurement to the frequency offset of the measured video signal Zero Time n sec Touch this soft key to select the total number of seconds to average the external frequency reference 14 VM700T Option 22 Video Wander Measurements User Manual Operating Basics LP Corner n Hz Use this soft key to select from the following measurement bandwidths 1 Hz 1 ns maximum peak jitter studio quality 0 5 Hz 2 5 ns maximum peak jitter contribution quality 0 2Hz 10 ns maximum peak jitter distribution quality Rescale Touch this soft key to automatically rescale the display for optimum viewing Peak Hold Touch this soft key to detect and hold the peak timing variations over the prior 17 seconds Drift Rate Measurement The constantly updated Drift Rate application calculates the rate of frequency drift of the horizontal synchronizing pulse frequency The rate of horizontal sync frequency drift has the greatest effect on studio quality recording and
25. ts after the channel letter representing the values of the lower and upper limits respectively Valid values for the limit numbers are between 999 0 and 999 0 ppb s OFRO OFRO specifies the lower and upper limits in ppb for the PAL Frequency Offset measurement The set command takes two arguments after the channel letter representing the values of the lower and upper limits respectively Valid values for the limit numbers are between 9999 0 and 9999 0 ppb VM700T Option 22 Video Wander Measurements User Manual B 3 Index C Configuration 2 Configuration file 2 Configuration file limits 7 Source Selection Video file 10 Video Source file 7 Configuration file deleting 6 D Done soft key 5 8 F Files rules for naming 4 7 System Default 5 8 K Keyboard Setl 4 Set2 4 0 Option 22 configuration 2 Option 22 specifications A 1 P Product description 1 R Remote control B 1 Remote commands B 2 S Soft keys Done 5 8 System Default 4 7 Source Selection Video file 10 Specifications A 1 System Default file 2 5 7 9 System Default soft key 4 7 V Video Source file 7 deleting 9 more information 9 VM700T Option 22 Video Wander Measurements User Manual Index 1
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