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User Manual VM700T Video Measurement Set Option 40/41/42

1. Audio Analyzer Select Special Change Plot Erase Limits Graph Setup Scales ON OFF Plot ON OFF Res ale Set Input Settling Range Time Default Settings Left Right P AUTO Range A E Range A E Range Level in Level in THD N THD N in Freq Views Volts dBu in Percent dB LOG LINEAR LOCKED UNLOCKED Graph Graph Graph View View View View Levels THD N Ch Sep Diff Left Right L amp R a The Settling Time menu displays the settings for plot conditions Each bold intensified text item can be selected and changed The Default Settings softkey returns the settings to default values as shown in the following Point plot conditions If the frequency remains within 0 100 and amplitude remains within 0 100 dB and above a threshold value of 60 00 dBu for 0 171 sec then plot a point every time the frequency changes more than 0 20 b Digitizing window choices are displayed under Set Input Range with a choice of five windows as follows The VM700T will digitize audio in a 92 dB window within a total input range of 132 dB There are five input range windows range A 62 to 30 dBu range B 72 to 20 dBu range C 82 to 10 dBu range D 92 to 0 dBu range E 102 to 10 dBu The View Diff softkey is displayed
2. Multitone Analyzer Change Set Input Set Ref Limits View Range Level On Off Rescale Displays Range Select menu Level at Ref Lvl Touch Softkey then Ref Freq n dBu knob o set n View View Left Ch Right Ch Levels Diff Dist N Dist N Press Menu button Average Change Set Input Numn View Range Cursors Rescale Touch softkey then turn the knob to set n Cursor 1 Cursor 2 Cursor 1 Cursor2 Tuchsoftkey ON ON Active Active knob to move cursor Left a Right 8 AUTO Range A E Range A E Range Nearest Peak pi itizing window choices are displayed under Set Input Range with a choice of five windows as ollows The VM700A will digitize audio in a 92 dB window within a total input range of 132 dB There are five input range windows range A 62 to 30 dBu range B 72 to 20 dBu range C 82 to 10 dBu range D 92 to 0 dBu range E 102 to 10 dBu Figure 2 13 The Multitone Analyzer menu tree VM700T Option 40 41 42 Audio Measurements User Manual 2 24 Operating Basics Multitone Analyzer Main Menu Change Change View displays four soft key selections that let you View change the display to view input signal levels the default mode view differences between le
3. Audio Limit Audio Source Audio Source Files Files Identification Auto Limit Camera Communi cation Files Testing Setup C Diagnostics Diagnostic cmponene Selection Errors Measure Limit Measurement Echo Rounding age UL uu E Files Locations ere NTSC Files In nvram ConfigFiles Switch Print Leave NTSC PAL File Directory Figure 1 2 Configure menus choices VM700T Option 40 41 42 Audio Measurements User Manual Getting Started Configuring the Touch the Audio Limit Files soft key to enter the Audio Limit Files Audio Limit Files directory The screen displays a series of audio limit standard or default files and if any have been created user limit files The file names appear in alphabetical order in the display as shown in Figure 1 3 You can select and press a soft key to display the parameters in any file but the parameters of the system default files cannot be modified If a default audio limits file is acceptable the VM 700T uses it if it is the selected file for making measurements on the input audio signals If you must modify the audio limits from the system defaults use the procedures given in the following text EndtoEnd LongHaul MediumHaul NewLimits ShortHaul System Default Satellite In nvram ConfigFiles Audio Limits Files D
4. sseseleeeeee I 3 7 Appendices Appendix A Audio Option Specifications ees A 1 Automatic Audio Test Specifications 0 0 0 cee eee eee eee A 1 Audio Analyzer Specifications 0 2 0 0 A 3 Audio Spectrum Specifications 0 0 eee cece eee eee A 4 Multitone Analyzer Specifications 22 0 0 0 0 e cece eee eee A 5 A V Timing Specifications Option 42 0 0 00 0 eee eee eee A 6 Appendix B Verification Procedures eee B 1 Test Equipment Required 0 0 cee eee eee eee B 1 Option 40 Sasss sers ev Sods e gare a ere Sha eae oe las ea a SUC goa Bs d B 3 Check Level Measurement Accuracy and Flatness 0 0 B 3 Specifications Checked 20 0 c cece cence eet teen eee B 3 Option 40 Level Accuracy and Flatness 000000000 B 3 Check Distortion and Distortion Measurement Accuracy B 5 Specification Checked 0 sierto eee idoni eee eee B 5 Option 40 Distortion Measurement Accuracy 0 0000 B 5 Check Frequency and Phase Measurement Accuracy 0 B 6 VM700T Option 40 41 42 Audio Measurements User Manual Table of Contents Specifications Checked 00 0 0 000 202 eee eee Option 40 Frequency Accuracy and Channel Phase Difference Option 41 Triple Input Audio cc cee cece wees Configuring Source Selection Audio 0 0 Che
5. In nvram ConfigFiles Audio Source Files Delete Create Rename Print Leave File File Directory Figure 1 6 Selecting an Audio Source file to use as a template 1 8 VM700T Option 40 41 42 Audio Measurements User Manual Getting Started 2 Touch the appropriate soft key for the file you want to use for example System Default 3 The screen displays a keyboard that you can use to type the name for your new file as shown previously in Figure 1 5 on page 1 5 Follow the file naming suggestions given on page 1 4 4 Press the Done soft key The VM 700T now displays the contents of the new file containing the audio source data from the file you selected as the template You can modify the parameters in this file Changing the Audio Source Parameters Change the Audio Source parameters using the following procedure 1 Rotate the knob to highlight the line containing the parameter you want to change 2 Select a parameter by touching it 3 Rotate the knob to change the parameter or value 4 Touch the Accept Input soft key to accept the change NOTE If you change a parameter and then decide you do not want to keep the change press the No Change amp Exit soft key The VM 700T 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
6. NOTE The Audio option processor circuitry runs independently of the VM 700T video sections This means that audio measurements may be captured for later display even while video capture and display operations are in progress However when the VM 700T is running an Audio option application it cannot simultaneously monitor the automatic test sequences Similar to the Audio Analyzer display the View Audio Auto Test measurement lets you capture an extremely detailed view of the automatic audio measure ments The information shown on the display varies with the type of test being received VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics The menu tree for the View Audio Auto Test measurement functions 1s shown in Figure 2 9 A short description of each choice is given on page 2 20 View Audio Autotest Show Graph Graph Graph Graph Text Levels Phase THD Crosstalk Rescale View View View View View Left Right Dif Rescale R L mae Rescale THD at THD at THD at View View Rescale TEST Level TEST 10dB TEST 15 dB Left Right Figure 2 9 The View Audio Auto Test menu tree The Show Text Display The Show Text display of the View Audio Auto Test shows the results of the current test Figure 2 10 shows the View Audio Auto Test screen display for
7. VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics 2 10 Audio Spectrum Main Menu Average Num Special Setup Change Channel Average Num specifies the time constant to be used for averaging The Average Num range is 1 256 the default value is 10 To change the Average Num value touch the Average Num soft key to highlight it rotate the knob until the selected time constant appears then press the Average Num soft key again Special Setup accesses the two measurement setup soft keys Set Input Range and Filter Select Change Channel switches the display between the left and right input channels To change the displayed input channel touch the Change Channel soft key to highlight it then touch the soft key for the desired display channel After selecting the input channel you may press the Menu button twice to redisplay the Audio Spectrum measurement soft keys NOTE The VM 700T can display distorted or incorrect signal information if the input range window is not matched to the input signal When the input range window and the input signal are not matched the VM 700T clips the input signal to the range of the window and displays the clipped signal Cursors High Res OFF ON Cursors places two cursors on the display and lets you position them to mark display features The numerical display shows the peak to peak signal level at each cursor s frequency location and the level differenc
8. dot to separate words in a name Forward slash and reverse slash are not permitted in the file name When neither Set 1 nor 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 sets 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 Set2 are unlocked by touching the same key again or touching the unselected key of the pair Shift is unlocked by touching Shift again VM700T Option 40 41 42 Audio Measurements User Manual Getting Started Please enter file name max 31 characters NewLimi tsi Eeee ed e EE GE Back AEAN EI PLU JEJCICHEJ GJCJ e sett Cancel set2 Space shift Figure 1 5 File naming keyboard m A maximum of 31 characters are allowed in a file or directory name m Use only uppercase and lowercase letters 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 Multiline directories and file names can be entered using the Return key Touch Return
9. frequency for test sequences that include a THD test sweep signal Graph Crosstalk plots crosstalk and noise vs frequency for test sequences that include a crosstalk test sweep signal Graph Levels Submenu View View Left display the left channel level test results Left View View Right displays the right channel level test results Right View View Diff graphs the level difference between the left and Diff right channels in dBu or volts Rescale Rescale restores the default scaling for the display Graph Phase Submenu Rescale Rescale restores the default scaling for the display Graph THD Submenu THD at THD at TEST Level graphs the results of the THD at TEST TEST Level Level portion of a test sequence containing a THD sweep test signal THD at TEST THD at TEST 10 dB graphs the results of the THD at TEST 10 dB 10 dB Level portion of a test sequence containing a THD sweep test signal THD at TEST THD at TEST 15 dB graphs the results of the THD at TEST 15 dB 15 dB Level portion of a test sequence containing a THD sweep test signal VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics View Left View Right Rescale View Left display the left channel test results View Right displays the right channel test results Rescale restores the default scaling for the display Graph Crosstalk Submenu View RoL View LR Rescale View R L plots the crosstalk from the right c
10. tor In frequency and phase mea surement accuracy procedure used to apply signal from one sine wave generator to both Option 40 inputs Used to connectthe sine wave generator to the triple VM 700T audio inputs of Option 41 Fabricated by user Fabricated by user DB 37 connectors are included with Option 41 a The TEGAM SG5010 sine wave generator requires a TEGAM TM500 or TM5000 series power module B 2 NOTE Before performing the level accuracy procedure Verify the sine wave generator level at 120 Hz by measuring with an accurate AC voltmeter such as a HP 3458A Digital Voltmeter You may also use an AC voltage calibrator such as a Fluke 5700A for this measurement Verify that the sine wave generator can meet the amplitude accuracy specifications listed in Table B 1 VM700T Option 40 41 42 Audio Measurements User Manual r Option 40 Use the following procedures to check the Option 40 Audio Option Check Level Measurement Accuracy and Flatness This procedure verifies flatness and measurement accuracy by checking signal levels at specified frequencies NOTE The actual frequencies and levels checked are not specified in this procedure If the measurement accuracy of certain frequencies and levels is important to your application we recommend that your test procedure include those frequencies and levels Specifications Checked Table B 2 lists audio option accuracy and flatness specifications Tabl
11. Audio Limit File 1 10 audio limit file creating 1 4 deleting 1 7 steps to modify parameters 1 3 audio limit files graphical displays in 1 6 Audio Limit files configuring 1 3 audio limits changing graphical elements 1 7 Audio Monitor functions configuring 2 6 Audio Monitor description 2 6 Audio option connecting to signal 1 12 Audio option measurements displaying 2 1 Audio Printout Title 1 10 audio source file specifying 1 11 audio source files configuring 1 7 editing procedure 1 8 Audio Source parameters changing 1 9 Audio Spectrum 2 8 Audio Spectrum Specifications A 4 Audio Video Timing Menu 2 34 Audio Video Timing measurement 2 33 Auto input range 2 5 set input range 2 12 Auto in set input range 2 25 Automatic Audio Test Specifications A 1 Average Num 2 10 2 27 VM700T Option 40 41 42 Audio Measurements User Manual B group keywords 3 6 bar graph display 2 6 begin configuration 1 1 button names list of front panel 3 3 C CCITT 2 14 CCITT recommended test sequences 2 16 Change Channel 2 10 Change Scales 2 2 Change View 2 25 changing audio limits 1 6 channel to channel crosstalk 2 17 Checkout VITS200 2 35 VITS201 2 38 command format 3 2 configuration steps 1 1 Configure button 1 1 Configure Files soft key 1 1 configuring audio source files steps 1 7 Cursor 1 On 2 27 Cursor 2 On 2 27 Cursor n Active 2 13 2 27 Cursors 2 10 2 27 cu
12. Audio Monitor Time Display 00 0c eee eee eens 2 7 Audio Monitor Time Display Menu 0002 02 ee ee 2 8 Audio Spectr m s scosecprem bre REB Be heb Baw PESCE PRSE ER 2 8 Audio Spectrum Main Menu sssseeeee ee eee eee 2 10 Special Setup Submenu unanenn e eee eee 2 12 Cursors Submenu ore E et aa ee 2 13 View Harmonics Submenu 00 eee eee eee eee 2 13 View Audio Auto Test 2 0 2 eee eect nee eens 2 14 The Show Text Display sisne cpana eene uae e ccc eens 2 15 TEK TESTZ93 reb gt pi bein ated es 2 17 TEK TEST 9S se icons 008 ang fo Nand Oot andes tM aE eh ardegt SaaS eh aha 2 18 Graphical Display of Audio Auto Test Signals 04 2 19 View Audio Auto Test Menu 0 cece eee eee 2 20 Graph Levels Submenu 0 0 eee cece eee teens 2 20 Graph Phase Submenu 0 cece eee eee eee eens 2 20 Graph THD Submenu 0 0 nurnure rrena 2 20 Graph Crosstalk Submenu 2 0 c eee eee eee eee 2 21 Multitone Analyzer 2 0 0 cette eh 2 22 Multitone Analyzer Main Menu 00 000 c eee eee eee 2 25 Change View Submenu sssssseesee eee 2 26 Left Channel and Right Channel Distortion Noise Submenu 2 26 Cursors SubMenu cere E ER 2 27 VM700T Option 40 41 42 Audio Measurements User Manual Table of Contents Option 41 and Option 42 eeeeeeee eene nn
13. Average Average Num specifies the time constant to be used for Num averaging The Average Num range is 1 256 the default value is 10 To change the Average Num value touch the Average Num soft key to highlight it rotate the knob until the selected time constant appears then press the Average Num soft key again Change Change View provides the same choices as show in the View previous change view submenu Set Input Set Input Range provides the same set input menu as Range previously described for setting the input signal range window Cursors Cursors places two cursors on the display and lets you position them to mark display features The numerical display shows frequency and level at each cursor location When both cursors are turned on the numerical display also shows the noise area between the cursors Rescale Rescale readjusts the vertical scale to make all of the plot visible on the display Cursors Submenu Cursor 1 Cursor 1 On turns on the first solid line cursor On Cursor 2 Cursor 2 On turns on the second dotted line cursor see On Figure 2 15 Cursor n Cursor n Active activate either cursor Once activated a Active cursor may be positioned on the display by rotating the knob Cursor 1 may not be positioned to the right of cursor 2 nor may cursor 2 be positioned to the left of cursor 1 The Nearest Peak soft key is available with either cursor active Nearest Nearest Peak positions the active cursor on the near
14. 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 will be retained while the most recent change or mistake is eliminated Editing an Audio Limit Graphic Element The VM 700T audio limit files contain graphical displays whose limits can be configured These include the following graphical displays m Amplitude response versus frequency characteristic these limits are used in the Audio Analyzer and View Audio Autotest measurement displays m Crosstalk plus Noise these limits are used in the View Audio Auto measurements display m Total harmonic distortion THD N these limits are used in the Audio Analyzer measurement display There are three ranges to make selections for limits for stimulus up to TEST 9 dB stimulus from TEST 10 dB to TEST 14 dB and stimulus greater than TEST 14 dB W Stereo phase difference these limits are used in the Audio Analyzer and View Audio Autotest measurement displays W Stereo gain difference these limits are used in the Audio Analyzer and View Audio Autotest measurement displays m Channel separation these limits are used in the Audio Analyzer measur
15. Tektronix Program 93 received from a Tektronix ASG 100 or ASG 140 Audio Signal Generator The display is different for each Auto Test as different measurements are made The numbers shown include the test program number and source test type and source name are decoded from the preamble of the audio test signal measure ment date and time and measurement status The measurement status shows one of three types of messages No Test Received OK or an error message If the measurement status is OK the display shows the test sequence Tek or O 33 Recommendation sent the program number of the test and a test source identifier The expected test levels for O 33 Recommendation test sequences are set at configuration these should match the test levels sent by the signal generator For Tek test sequences however the Audio Option ignores the audio levels set at configuration Instead the Audio Option gets its expected test level information from the preamble of the received test sequence NOTE The Audio option normally receives the test sequence preamble on the left channel If left and right channel inputs are reversed the Audio option views the test and indicates the signal reversal by displaying Swapped rather than Normal Stereo Channel Assignment VM700T Option 40 41 42 Audio Measurements User Manual 2 15 Operating Basics View Audio Auto Test At Sat Aug 10 12 54 31 1996 Video Source A Test Type Tektroni
16. 5 Table 3 3 Group B Keywords for Audio Source Selection 3 6 Table 3 4 Option 40 Group W Keywords for Audio Source Selection 3 7 Table 3 5 Option 41 Group W Keywords for Audio Source Selection 3 7 Table A 1 O 33 Automatic Audio Test Measurement Specifications A 1 Table A 2 Tektronix Automatic Audio Test Measurement Specifications A 2 Table A 3 Frequency and Noise Specifications 000 A 3 Table A 4 Accuracy and Flatness Specifications 0 A 4 Table A 5 General Audio Spectrum Specifications A 4 Table A 6 Audio Spectrum Level Measurement Specifications A 4 Table A 7 Harmonic Analyzer Measurement Specifications A 5 Table A 8 Miscellaneous Specifications 00 0000 00 0000 A 5 Table A 9 Multitone Analyzer Measurement Specifications A 5 Table A 10 Audio Video Timing Measurement Specifications A 6 Table B 1 Test Equipment Required for Verification Procedures B 2 Table B 2 Accuracy and Flatness Specifications 00 B 3 Table B 3 Example Test Signals for Level and Flatness Test B 4 Table B 4 Accuracy and Flatness Specifications 00 B 10 Table B 5 Example Test Signals for Level and Flatness Test B 11 VM700T Option 40 41 42 Audio Measurements User Manual IEEE eS eee Preface T
17. Audio Signal Generators that are also equipped with the Audio Video Timing measurement VM700T Option 40 41 42 Audio Measurements User Manual Getting Started i 4 Getting Started This section discusses configuring Audio Option 40 and connecting it to an audio source Configuration and connections required for Option 41 different from those found here are discussed in Option 41 and Option 42 beginning on page 2 29 Those differences are configuring the Source Selection file and making input connections to the three channel inputs of Option 41 Configuring the Audio Option The approach to configuring the VM700T Audio option is similar to that used for its video functions Refer to the VM700T Option 01 NTSC amp Option 11 PAL User Manual if you need additional information on configuring the VM 7007 A series of files and directories provide default parameters that the VM 700T uses to measure audio signals If your application requires parameters other than the defaults supplied with the VM 700T you can configure the Audio option according to your preferences To configure the Audio option and use the new parameters in audio measurements you must perform these tasks W Create your own Audio Limit file for example NewLimi ts and configure it with your limits W Create your own Audio Source file for example NewSource and select NewLimi ts as the limits file to be used m Configure the Source Selection file to select the NewS
18. Q 600 Q and 10 KQ Selects the type of Lissajous display used in the Audio Monitor Choices are X Y Oscilloscope or Soundstage the default Selects the meter ballistics for the bar graph level meters in the Audio Monitor display Choices are PPM DIN 45406 the default PPM NORDIC PPM TEK7601 or VU Choices are 15 or 30 seconds or 1 2 5 30 or 60 minutes or disabled the default If enabled this selection causes the VM700T to report an error if silence missing or out of limit test signal is encountered for more than the selected time Choices are enabled or disabled the default If enabled this selection causes the VM 700T to append an audio report to the report file in Video Auto mode Supplies the text for the title at the top of report printouts You can select the audio printout title for editing by touching it then entering the new title on the displayed keyboard Press the Done soft key when you have finished editing the Audio Printout Title text 1 Similar to the Tektronix 760 meter face but with its 8 dB tick mark labeled TEST The lineup level is at the TEST or 8 dB tick on this meter Ballistics are the same as for the DIN 45406 meter VM700T Option 40 41 42 Audio Measurements User Manual Getting Started Configuring Refer to Option 41 and Option 42 beginning on page 2 29 for configuring the Source Selection Audio Option 41 signal source selections for Option 40 The audio limit fi
19. Results in file Audio Monitor The hardkey command indicates the press and release of the specified front panel button button_name Using the hardkey command is equivalent to entering hardpress and hardrelease however in general the hardkey command should be used instead of these commands Example VM700T gt hardkey Menu Front panel button names are listed in Table 3 1 Table 3 1 Front Panel Button Names A Display Picture Auto Freeze SelectLine Average Graticule Vector B Help Waveform C Menu XY Arrow selector Copy MoveExpand VM700T Option 40 41 42 Audio Measurements User Manual Remote Commands and Keywords 3 4 set keyword channel_letter value value2 show filename softkey softkey name NOTE The Configure Function and Measure buttons cannot be selected through remote The set command defines the configuration values to be used during the remote session The keywords available for set are listed in Table 3 1 Table 3 2 and Table 3 3 The channel letter is A B or C The configuration 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 restoreconfig Example VM700T set BING A 0 5 0 5 The above example changes the limits fo
20. THD N at 400 Hz m Polarity m Stereo Channel Assignment m Crosstalk into channel dB m ANSI Crosstalk dB m ANSI SNR weighted dB m Gain Difference dB m Phase Difference deg NOTE The ANSI Crosstalk measurement has a noise floor threshold a result is not displayed in the ANSI Crosstalk dB report line unless the measured ANSI SNR weighted dB measurement is less than 100 dB in both channels VM700T Option 40 41 42 Audio Measurements User Manual 2 18 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com Operating Basics Graphical Display of You can display graphs of the left and right channel frequency sweeps showing Audio Auto Test Signals differential gain and differential phase over the frequency sweep the THD N of each channel for those test sequences having a THD N sweep signal and Crosstalk between channels again only for those test sequences have a crosstalk sweep test A typical View Audio Auto Test screen see Figure 2 11 graphs the signal phase and frequency for left and right audio channels In Option 41 it is the left and right channels associated with the selected video channel A B or C The soft key menu choices determine the type of display shown The upper and lower test limits are shown in the View Audio Auto Test graphic displays as lighter lines above and below the received signal see Figure 2 11 for
21. W keywords for Option 41 and their meanings Table 3 5 Option 41 Group W Keywords for Audio Source Selection Keyword Description Keyword Description WACA Source A Audio Config File WAIA Source A Audio Input WACB Source B Audio Config File WAIB Source B Audio Input WACC Source C Audio Config File Source C Audio Input VM700T Option 40 41 42 Audio Measurements User Manual Appendices Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com ILL N Appendix A Audio Option Specifications Automatic Audio Test Specifications Table A 1 0 33 Automatic Audio Test Measurement Specifications Measurement Range Accuracy Includes Flatness Insertion Gain Error 6 dB 0 2 dB Sweep Gain Min and Max 12 dB 10 1 dB THD N at 1020 Hz lt 0 03 to 70 10 1 digit 2nd Harmonic at 60 Hz lt 0 03 to 70 10 1 digit 3rd Harmonic at 60 Hz lt 0 03 to 70 10 1 digit Crosstalk into channel e 1 dB Test Level 6 dBu lt 66 dB to 0 dB 0 dBu lt 60 dB to 0 dB 6 dBu lt 54 dB to 0 dB SNR unweighted 4 1 dB Test Level 6 dBu 10 dB to gt 76 dB 0 dBu 10 dB to gt 70 dB 6 dBu 10 dB to gt 64 dB SNR weighted 4 2 dB Test Level 6 dBu 10 dB to gt 76 dB 0 dBu 10 dB to gt 70 dB 6 dBu 10 dB to gt 64 dB Max Compandor Error rise fall 6 dB 0 2 dB Gain Difference 12 dB 0 2 dB Phase Difference 180 to 180 1 a A
22. a known signal Specification Checked THD N accuracy is 10 of the reading 1 digit for harmonics at input levels of 20 dBu or greater in a 33 Hz to 22 kHz bandwidth Option 40 Distortion 1 Check residual THD N Measurement Accuracy a Apply a signal between 20 dBu and 30 dBu in amplitude from a sine wave generator to the VM 700T Audio Option 40 See Figure B 2 for a cabling diagram The generator should be set at 50 Q output resistance N To Option 40 Audio Input Connector Figure B 2 Option 40 cable connections for distortion measurement accuracy check VM700T Option 40 41 42 Audio Measurements User Manual B 5 Appendix B Verification Procedure b Runthe Audio Analyzer measurement and verify that residual THD N is 0 03 or less An applied signal of 8 dBu to 10 dBu yields an optimal reading while a 20 dBu signal yields a worst case reading 2 Check THD N Measurement Accuracy a With 600 Q output resistance selected connect the outputs of two sine wave generators in parallel to the left channel input of the Audio Option See Figure B 2 for a cabling diagram b Set one sine wave generator for a 2 Vpms output at 1 kHz c Set the second sine wave generator for a 0 02 V 20 mVgygs at 3 kHz These two signals add across the termination resistance to produce a 1 kHz signal with a 1 third harmonic distortion d Runthe Audio Analyzer measurement and check for a THD N reading of 0 9 to 1 1 3 M
23. a sample display As described earlier these limits are set either at configuration for O 33 Recommendation sequences or are contained in the received sequence s preamble in Tek sequences The default lower test limit is a mirror of the upper test limits You may configure the elements of the View Audio Auto Test function in the VM 700T Configure Files directory For information on configuring View Audio Auto Test refer to Configuring the Audio Option beginning on page 1 1 View Audio Auto Test At Mon Oct 14 11 29 31 1991 Video Source A Audio Input 1 Test Type 0 33 Program 01 Expected TEST level 0 dBu Source TEK1 Interchannel Phase Difference degrees ES uS ae are TE uA URL NEN der day f i 7 40 80 200 400 800 2k Show Graph Graph Graph Graph Text Levels Phase THD Crosstalk Figure 2 11 Typical View Audio Auto Test graph phase display showing upper and lower test limits faint lines 4k 8k 16k VM700T Option 40 41 42 Audio Measurements User Manual 2 19 Operating Basics 2 20 View Audio Auto Test Menu Show Text Graph Levels Graph Phase Graph THD Graph Crosstalk Show Text displays the tabular text display of the measure ments and results obtained during a test run Graph Levels plots the left channel right channel and difference levels from the tone sweep Graph Phase plots inter channel phase difference Graph THD plots total harmonic distortion and noise vs
24. 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 will be retained while the most recent change or mistake is eliminated VM700T Option 40 41 42 Audio Measurements User Manual Getting Started 1 10 The parameters in the Audio Source file are Audio Limit File Error Reporting 0 33 Test Level Lineup Level External Termination Lissajous Display Level Meter Dead Air Alarm Report in Audio Audio Printout Title Selects the Audio Limit file in the Audio Limit Files directory used by the VM 700T Enabled or disabled the default Enabling this selection adds the reported audio errors for the specified audio source to the video error report that is output when the Log logical port is configured see Configuring the Communications Port in the VM 700T Video Measurement Set Option 01 NTSC amp Option 11 PAL User Manual Sets the O 33 test level Choices are 3 dBu 0 dBu or 6 dBu Choices for the Lineup Level are 10 dBu to 10 dBu the default is 0 dBu This selection sets the meter equivalency for the VU and dBu scales used in the Audio Monitor display Selects the VM 700T external termination Choices are 50 Q 75 Q 125 Q 150 Q 300
25. naming toggle keys is to use the function name with appropriate capitalization up to but not including the colon For example the soft key command to toggle the plot on or off in the Audio Analyzer measurement function looks like this VM700T gt softkey Plot Get and Set Command Keywords Group A Keywords Group B Keywords The following sections documents the audio keywords used with the get and set commands For each get set keyword letter group it gives the syntax of the set command and the get result and an explanation of what the keywords in the letter group do This is followed by an alphabetized table of keywords in the group and their meaning Group A keywords report on or set the values of Audio option Configuration parameters These keywords can be used only on a VM700T equipped with either the Option 40 or the Option 41 Audio Option Get commands used with the Group A keywords have the following form get lt keyword gt lt channel letter gt Set commands used with Group A keywords have the following form set lt keyword gt lt channel letter gt lt argument gt where lt argument gt is the text to which the setting associated with the keyword is to be set Table 3 2 lists the keywords in Group A and their meanings Table 3 2 Group A Keywords for Audio Configuration Keyword Description Keyword Description A33T 0 33 test level ALEM Level Meter ADAA Dead Air Alarm ALIL Lineup level AERR Error repor
26. of 70 dBu to test for worst case Table B 5 shows an example selection of test frequencies and amplitudes 6 Setthe sine wave generator for each of the selected frequencies and amplitudes a Record the level of each frequency b Verify that the measured levels recorded for each frequency are within the flatness specification given in Table B 2 on page B 3 Table B 5 Example Test Signals for Level and Flatness Test Frequency 30 Hz 100 Hz 1kHz 5 kHz 12 kHz 20 kHz 7 Repeat step 5 for channels B and C VM700T Option 40 41 42 Audio Measurements User Manual Amplitudes 10 dBu 21 dBu 40 dBu 49 dBu 51 dBu 55 dBu 59 dBu 61 dBu 65 dBu 70 dBu B 11 Appendix B Verification Procedure Check Distortion and Distortion Measurement Accuracy This procedure verifies that residual THD N is lt 0 03 then checks the THD N measurement accuracy by reading a known signal Specification Checked THD N accuracy is 10 of the reading 1 digit for harmonics at input levels of 20 dBu and greater in a 33 Hz to 22 kHz bandwidth Option 41 Distortion 1 Check residual THD N Measurement Accuracy a Apply a signal between 20 dBu and 30 dBu from a sine wave generator to the VM700T Audio Option See to Figure B 4 for connections b Run the Audio Analyzer measurement and verify that residual THD N is 0 03 or less An applied signal of 8 to 10 dBu yields an opti
27. switch the audio input channel just as they change the video input source channel In Audio Monitor and in the A V Timing measurement a message will be displayed to tell you which input channel is being monitored Touch the highlighted audio input 1 2 or 3 to select it Rotate the front panel knob to change the audio input selection Touch the highlighted source file to select it SN xe ow c Rotate the front panel knob to change the audio source file selection if you are using an audio source file other than the system default 7 When you have specified the audio inputs and source files touch the Accept Input soft key 8 Ifthe change is correct touch the Update amp Exit soft key otherwise touch the No Change amp Exit soft key NOTE If you change audio input and source files and then decide to exit the directory and cancel the change you must press the Accept Input soft key followed by the No change amp Exit soft key The VM 700T verifies that you want to exit the Source Selection Audio directory and cancel any changes by asking you to touch the No change amp Exit soft key again The VM 700T with Option 41 includes a 37 pin connector located on the instrument back panel Pin assignments for the connector are listed in Table 2 1 Table 2 1 Audio Option 41 Connector Pin Assignments Audio Input Signal Signal Shield 1 Left 1 2 3 1 Right 21 22 20 2 left 4 5 6 2 Right 24 25 23
28. 0 milliseconds Display Pk Hold Time On Figure 2 4 The Audio Monitor time display VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics Audio Monitor Time Display Menu Display Display Time switches the display to a format that shows a Time Lissajous display of the phase relationship between the two channel signals Pk Hold Pk Hold ON OFF enables or disables the bar graph peak hold ON OFF function This function retains peak signal levels for a few seconds when on Audio Spectrum The Audio Spectrum measurement measures and displays an audio signal on a frequency and level scale Figure 2 5 shows the Audio Spectrum display Note that this illustration is a screen capture of the third acquisition in a 10 acquisition average display Audio Spectrum Input Number 1 Level 188 Hz 20 kHz 2 93 dBu Range AUTO jo Right Channel Level dBu Weighting Filteri Nones 12 L Sa E SE FD EU LU CE x BUM 0 5000 10000 15000 20000 Hz Cursorl 12328 Hz 23 Hz 3 28 dBu Average 3 10 Average Special Change Cursors High Res View Rescale Num 10 Setup Channel OFF Harmonics Figure 2 5 The Audio Spectrum display VM700T Option 40 41 42 Audio Measurements User Manual 2 8 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com Operating Basics This display plots frequency on the x axis and signal level in dBu on the
29. 010 100 dB Required for all Option 40 and Option 41 verification proce dures TEGAM SG5010 two are needed to check distortion measurement accuracy a Adapter cable three banana plug to one male XLR 2 re quired XLR connectors must be wired to current AES recommenda tions pin 1 ground pin 2 hot pin 3 cold Connects sine wave generator to adapter cable supplied with VM 700T Option 40 E Z Hook 5023 xx or equiva lent Female XLR to male mini XLR adapter cable 2 required Dual female XLR to single male XLR connector Supplied with VM 700T Option 40 XLR connectors must be wired to current AES recommenda tions pin 1 ground pin 2 hot pin 3 cold See Figure 1 7 on page 1 12 for XLR connector pin locations For level accuracy level flat ness frequency and phase measurement accuracy proce dures In distortion measurement procedure connects two sine wave generators to one Op tion 40 input Supplied with Option 40 Fabricated by user Dual male XLR to single female XLR connector mates with 2 female XLR to male mini XLR adapter cables Dual female XLR to DB 37 female adapter cable XLR connectors must be wired to current AES recommenda tions pin 1 ground pin 2 hot pin 3 cold XLR connectors must be wired to current AES recommenda tions pin 1 ground pin 2 hot pin 3 cold See Figure 2 17 on page 2 31 for pin outs ofthe VM 700T female DB 37 connec
30. 3 Left 7 8 9 3 Right 27 28 26 a For single ended input connect single ended inputs to a Signal pin connect Signal pin to shield VM700T Option 40 41 42 Audio Measurements User Manual Option 41 and Option 42 Audio Signal Tektronix supplies a DB 37 mating connector kit with Option 41 to assemble the Interconnection Cable signal interconnection cabling The supplied kit provides several sizes of cable adapter collars Select the one fits your cable and put it on the cable before assembling the wiring to the connector as shown in Figure 2 16 See Table 2 1 for the connector pin assignments The connector pin locations are shown in Figure 2 17 The Tektronix part number for the DB 37 connector is 200 3947 00 Figure 2 16 Orientation of the cable adapter collar Input3 Input2 Input 1 right righ ht ight TIR z E 3 Male DB 37 Input 3 input 2 Input left left left Figure 2 17 Option 41 Triple Input Audio input connector pin locations After assembling the connector and checking out the wiring install the EMI reduction ferrite choke EMI Reduction Ferrite The EMI reduction parts consist of two ferrite forms and two cable tie wraps to Choke secure the ferrite forms on a multiconductor cable The ferrite forms fit together on a cable that has an outside diameter of 0 5 inch or less The ferrite choke consists of the following parts Ferrite forms 2 e
31. ASG 140 for Active Video Checkout When the VITS 201 is in the power up Line Selection mode and is genlocked the signal at pin 14 of the remote connector will be a TTL low voltage for 4 5 seconds and then high for 0 5 seconds The signal transitions from low to high at line 1 field 1 When the TTL signal is high the audio output is ON but the text inserted by the VITS 201 does not become visible until active video This delay time is subtracted out of the VM 700T A V Timing measure ment NOTE This checkout forces the VITS 201 into Standby Mode It can be used only when the VITS 201 is out of service VM700T Option 40 41 42 Audio Measurements User Manual 2 39 E a Remote Commands and Keywords D 4 Remote Commands and Keywords Like the VM700T video functions remote control of the Audio option functions is performed through either the serial RS 232C ports or if Option 48 is installed the GPIB port on the VM 700T rear panel Operating the VM 700T remotely using the RS 232 interface requires that you connect a terminal or computer to the VM700T through one of the RS 232C ports Port 0 or Port 1 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 VMT application The VMT software offers a choice of either menu selection or command line entry of VM700T remote commands Remote operation of the VM700T through the GPIB interface requires a s
32. D is on Checkout Grounding pin 1 of the remote connector turns off the audio output VITS 200 Instructions This procedure is used to place the signal in the vertical interval 1 Connect a NTSC video source so that the VITS 200 is genlocked 2 From the front panel select Vertical Characters VERT CHAR 2 ENABLE 3 Input the message you intend to use 4 Connect a special cable between the VITS 200 remote connector and the ASG100 remote connector as shown in Figure 2 20 Checkout When the VITS 200 is genlocked the signal at pin 20 of the remote connector will be a TTL HIGH voltage for 4 5 seconds and then LOW for 0 5 seconds The signal transitions from high to low at line 262 field 3 The audio output is turned ON at this time but the text inserted by the VITS 200 does not appear until field 1 line 11 The VM700T Audio Video Timing measurement removes this delay time before presenting the measured time difference NOTE The wiring diagram in Figure 2 20 selects message number 2 by grounding pin 2 You can select any of the 15 possible messages by grounding different selection lines pin 2 3 4 or 5 VM700T Option 40 41 42 Audio Measurements User Manual 2 35 Option 41 and Option 42 2 36 VITS200 ASG100 ASG140 Figure 2 20 Cabling between the VITS 200 and the ASG 100 ASG 140 for Vertical Interval Placing the Signal in the Active Video This procedure is used to place the signal in the active
33. Hz VM700T Option 40 41 42 Audio Measurements User Manual A 3 Appendix A Audio Option Specifications Table A 4 Accuracy and Flatness Specifications Accuracy Includes Frequency Range Level Range Flatness Flatness 20 40 Hz 2 20dBu 0 3 0 2 dB 0 1 0 2 dB 20 dBu to 50 dBu 0 41 0 3 dB 0 1 0 2 dB 50 dBu to 60 dBu 0 6 0 5 dB 0 1 0 2 dB 60 dBu to 70 dBu 1 0 dB 0 1 0 2 dB 40 Hz 20 kHz gt 20dBu 0 2 dB t 0 1 dB 20 dBu to 50 dBu 0 3 dB t 0 1 dB 50 dBu to 60 dBu 0 5 dB t 0 1 dB 60 dBu to 70 dBu 1 0 dB t 0 1 dB a Leveldifferences between channels is 0 2 dB at levels of 50 dBu and greater Audio Spectrum Specifications Table A 5 General Audio Spectrum Specifications Specification Description Normal Res Mode High Res Mode Display bandwidth DC to 24 kHz Any 3 kHz within the display bandwidth Frequency resolution 41Hz 6 Hz Cursor readout accuracy Frequency 24 Hz 3 Hz Amplitude 0 5 1 0 dB 0 5 1 0 dB Frequency range for noise level 188 Hz to 20 kHz Selected 3 kHz window within the range of measurement Signal Noise ratio gt 85 dB at full scale Table A 6 Audio Spectrum Level Measurement Specifications Frequency Range 188 Hz 20 kHz A 4 Level Range 2 20 dBu 20 dBu to 50 dBu 50 dBu to 60 dBu 60 dBu to 70 dBu Accuracy 0 2 dB 0 3 dB 0 5 dB 1 0 dB 24 Hz to 24 kHz gt 70 dB for inputs gt 20 dBu with appro
34. Test Equipment Depot User Manual 1 800 517 8431 Tektronix PA VM700T Video Measurement Set Option 40 41 42 Audio Measurements 070 9656 00 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com IINE AIXEXEAENIAEELEDEE J Table of Contents Preface b en ehe o RR E ERREMESP USER MUS SEU USER NEN ER vii Getting Started Configuring the Audio Option 000 cece eee eee 1 1 Configuring Procedure 0 00 cece cece teens 1 1 Configuring the Audio Limit Files 0 0 0 0 cee eee eee eee 1 3 Creating an audio limit file 2 0 0 02 eee eee 1 4 Deleting a modified audio limit File 00 00 e eee eee 1 7 Configuring the audio source files 00 00 ce eee eee eee 1 7 Configuring Source_Selection Audio for Option 40 1 11 Connecting toa Source 2 0 cee ete en 1 12 Input Connector Pin Assignments 00 00 cece cece eee 1 12 Operating Basics Audio Analyzer 2er ie ee e eth ae I han antiga baa 2 1 Audio Analyzer Main Menu 0 000 c eee eee eee 2 2 Select Graph Submenu 0 cece ee eens 2 4 Special Setups Submenu 0 02 cece ee eee 2 5 Change Scales Submenu 0 0 0 e eee eee ee 2 5 Audio MOnItOE asss e nena jetta Poa POS otek BEG MER PERS LER RRR ae 2 6 Audio Monitor Phase Display Menu 0 02 02 ee ee 2 7
35. VM700 family of Video Measurement Sets The three separate inputs of Option 41 enables the VM 700T to measure the audio signals from three stereo audio sources With minor differences Option 41 operates like Audio Option 40 These include the following differences m configuration of the Source Selection Audio file W rear panel connector type and pin assignments The following paragraphs describe these differences Other information about the operation of the VM 700T Audio Option is contained in the preceding sections of this manual Option 41 is configured like Option 40 except for the Source Selection Audio file The Source Selection Audio file lets you specify an Option 41 audio input 1 2 or 3 for a video source A B and C and then select an appropriate audio source file if you want to use an audio source file other than the system default To specify audio inputs and audio source files for video sources use the following procedure 1 From Measure Mode press the Configure front panel button touch the Configure Files soft key followed by the Source Selection Audio soft key 2 Rotate the front panel knob to highlight the source A B or C for which you are specifying an audio input and an audio source file VM700T Option 40 41 42 Audio Measurements User Manual 2 29 Option 41 and Option 42 Back Panel Audio Connector Pin Assignments 2 30 NOTE With Option 41 the front panel channel select buttons
36. a Tektronix part number 274 0832 00 Cable tie wraps 2 ea Tektronix part number 344 0120 00 When installed as described on the assembled audio cable the ferrite forms act as a choke to reduce the level of high frequency noise emitted from the signal interconnection cabling VM700T Option 40 41 42 Audio Measurements User Manual 2 31 Option 41 and Option 42 2 32 Installation Instructions Install the ferrite cores after assembling the cable to the supplied connector Use the included tie wraps to hold the two ferrite halves in place on the cable 1 Place a cable tie wrap around the cable with the tie wrap end started through the tie binder to form a loop Place both ferrite forms on the cable as shown in Figure 2 18 The parts must be placed as close to the to the connector as possible Slide the loop of the tie wrap over the two ferrite halves and tighten the tie wrap firmly Trim off the excess end of the tie wrap Place an additional tie wrap around the cable behind the ferrite forms to eliminate the possibility of the assembled parts slipping on the cable Tighten the tie wrap on the cable and trim off the excess end unu ETT Hil Figure 2 18 Ferrite forms installed on the signal interconnection cable VM700T Option 40 41 42 Audio Measurements User Manual Option 41 and Option 42 Audio Video Timing Option 42 VM700T Audio Video Measurement Operatin
37. audio input signal is not checked against the limits they may have been selected during configuration Rescale Rescale readjusts the vertical scale to make all of the plot visible on the display VM700T Option 40 41 42 Audio Measurements User Manual 2 25 Operating Basics 2 26 MULTITONE ANALYZER Range L AUTO Range R AUTO Analyzed signal MTone4 DistortiontNoise on Left Ch dBu 0 5000 10000 15000 20000 Hz Average Off View View Right Ch Levels Diff Dist N Figure 2 14 The Multitone Analyzer distortion plus noise components versus frequency display Change View Submenu View View Levels displays a graph of the channel signal levels Levels View View Diff displays a graph of the difference between the two Diff channel signals Left Ch Left Ch Dist N display a new graph of the signal Dist N distortion noise in the left channel see Figure 2 14 Pressing the Menu front panel button accesses a new set of soft key menu choices Right Ch Right Ch Dist Ndisplay a new graph of the signal Dist N distortion noise in the right channel Pressing the Menu front panel button accesses a new set of soft key menu choices Left Channel and Right Channel Distortion Noise Submenu The following soft key choices are accessed by pressing the Menu button with the Left or Right Channel Distortion Noise displays active VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics
38. button is lit Selecting a measurement or diagnostic application is equivalent to touching the selection soft key Example VM700T execute Audio Analyzer You may run the following audio applications under remote control Be sure to use the same capitalization and tildes as shown Audio Analyzer Audio Monitor Audio Spectrum Calibrate AudioBoard Identify Audio Hardware View Audio Auto Test VM700T Option 40 41 42 Audio Measurements User Manual Remote Commands and Keywords get keyword channel letter getresults hardkey button_name The get command returns the configuration file value specified by keyword on the channel specified by channel_letter Refer to Get and Set Command Keywords on page 3 5 for a list of the available keywords for the Audio options The channel_letters available are A B or C Example VM700T gt get BSNR A The above example returns the signal to noise ratio limits for channel A 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 VM700T gt getresults
39. ck Level Measurement Accuracy and Flatness Specifications Checked 00 cece cee eee eee eee Option 41 Level Accuracy and Flatness Check Distortion and Distortion Measurement Accuracy Specification Checked 11 0 0 0 eee eee eee eee ee Option 41 Distortion Measurement Accuracy Check Frequency and Phase Measurement Accuracy Specifications Checked 0 0 eee cee eee eee eee Option 41 Frequency Accuracy and Channel Phase Difference Index VM700T Option 40 41 42 Audio Measurements User Manual eccccc n B 6 B 6 B 9 B 9 B 10 B 10 B 10 B 12 B 12 B 12 B 13 B 13 B 13 Table of Contents List of Figures Figure 1 1 The Configure menu 00 0 0 cece eee 1 2 Figure 1 2 Configure menus choices 0 0 0 0 cece eee ee eee 1 2 Figure 13 Audio Limit menu choices 0 0 0 0 e eee ee eee 1 3 Figure 1 4 Selecting an Audio Limit file to use as a template 1 4 Figure 1 5 File naming keyboard 00 0 0 eee eee eee 1 5 Figure 1 6 Selecting an Audio Source file to use as a template 1 8 Figure 1 7 Cables and connectors supplied with Audio Option 40 1 12 Figure 1 8 Option 40 connectors and pin assignments 1 12 Figure 2 1 The Audio Analyzer display 0 33 test sequence 2 1 Figure 2 2 The Audio Analyzer menu tree
40. digit whichever is worse for inputs of 60 dBu and greater in the frequency range of 20 Hz to 20 kHz Channel phase difference 1 for inputs of 40 Hz to 20 kHz 2 for inputs of 20 Hz to 40 Hz at levels of 40 dBu and greater As in Figure B 4 connect the sine wave generator output to the Audio board Set the sine wave generator for a frequency and amplitude in the specified frequency and amplitude range of the Audio option 20 Hz to 20 KHz amplitude of 60 dBu or greater NOTE Use a test signal level of at least 60 dBu and test at least 10 frequencies over the entire range Tested frequencies should include the specification limits 20 Hz 20 kHz and the 40 Hz breakpoint Example frequencies to test might also include the following 100 Hz 200 Hz 1 kHz 2 kHz 10 kHz 3 Check that the measured frequency is accurate to the limits shown in Table B 4 for the applied test signal frequency and level and that the phase difference between channels meets the phase difference specification VM700T Option 40 41 42 Audio Measurements User Manual B 13 Index Index A A group keywords 3 5 A V Timing Specifications A 6 ACG OFF ON 2 7 Active Video 2 34 active video VITS200 2 36 VITS201 2 38 alarms 2 16 ANSI 2 14 ANSI Crosstalk 2 18 ANSI SNR 2 18 Audio analyzer features 2 2 Audio Analyzer Specifications A 3 Audio analyzer purpose 2 1 audio keywords 3 5 audio limit changing parameters 1 6
41. e ment display VM700T Option 40 41 42 Audio Measurements User Manual Getting Started You can change the limit of any graphical element by touching it on the screen The screen displays the parameter s upper and lower limits in tabular form at the bottom of the display Modify these elements with the following procedure 1 Touch the graphical element to display its upper and lower limit values 2 Rotate the front panel knob to highlight the parameter you want to change 3 Youcan change the value of the selected parameter in either of two ways touch the parameter value and rotate the front panel knob to raise or lower it then press the Accept Input soft key or touch the graphical display of the parameter you want to change then rotate the front panel knob to raise or lower its value In either case the graphical display and values change to match your input Touch the Accept Input soft key to accept the changes Touch the Done soft key Rotate the front panel knob to move to other parameters in the file cU ee usd When you have completed the changes to your custom Audio Limits file press the Update amp Exit soft key Deleting a Modified You can delete a modified audio limit file with this procedure Audio Limit File TER ET 1 Inthe Audio Limit Files directory touch the Delete soft key The query line the top line of the display asks you to select a file to be deleted 2 Select the file to be deleted by touching i
42. e B 2 Accuracy and Flatness Specifications Accuracy Frequency Range Level Range includes flatness Flatness 20 40 Hz gt 20 dBu 0 3 0 2 dB 0 1 0 2 dB 20 dBu to 50 dBu 0 4 0 3 dB 0 1 0 2 dB 50 dBu to 60 dBu 0 6 0 5 dB 0 2 0 3 dB 60 dBu to 70 dBu 1 0 dB 0 4 0 5 dB 40 Hz 20 kHz gt 20 dBu 0 2 dB 0 1 dB 20 dBu to 50 dBu 0 3 dB 0 1 dB 50 dBu to 60dBu 0 5dB 0 2 dB 60dButo 70dBu 1 0cB t 0 4 dB a Leveldifference between channels is 0 2 dB at levels of 50 dBu and greater Option 40 Level 1 Power on the VM 700T and associated test equipment and let them warm up Accuracy and Flatness for 20 minutes 2 Connect the sine wave generator to the VM 700T audio option left and right mini XLR input connectors See Figure B 1 for an example of cabling VM700T Option 40 41 42 Audio Measurements User Manual B 3 Appendix B Verification Procedure NOTE For this connection you may want to use the two female XLR to male mini XLR adapter cables supplied with the VM 700T If you do you will need to furnish or fabricate an adapter on the signal generator end To Option 40 Audio Input Connectors Figure B 1 Option 40 cable connections for level accuracy and flatness check 3 Press the Measure hard key select Audio and run the Audio Analyzer measurement 4 Using a known accurate sine wave generator or one verified with an accurate AC voltmeter a
43. e between them When both cursors are turned on the numerical display also shows the noise area between the cursors The cursor submenu permits positioning and selection of the cursors High Res OFF ON selects view resolution When high resolution mode is off the default the VM 700T displays 24 kHz of the selected channel s audio spectrum When high resolution mode is on the VM 700T displays a 3 kHz window of the 24 kHz display see Figure 2 7 The position of the window in the 24 kHz spectrum can be adjusted by rotating the control knob NOTE Filter selection is not available in High Res mode VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics Audio Spectrum Input Number 1 Level 24 Hz 3 00 kHz 93 06 dBu Range AUTO Right Channel Level dBu Weighting Filter Not Available 100 110 120 AAA M LA ein M E Md hi ee ia Y 1000 1500 2000 2500 3000 Hz Average 2 gt reum ee Ee fem Fate Res peak pene reum ee Ee peak Figure 2 7 The Audio Spectrum display in High Res mode View View Harmonics brings up the Harmonic Analyzer measure Harmonics ment display Touching this soft key displays the harmonics of a selected frequency in the 35 Hz to 10 kHz range see Figure 2 8 The View Harmonics menu choices permits selection of the harmonic type to be displayed The Harmonic Analyzer displays the selected fundamental frequency and six harmonics in a bar graph level dB
44. ect Filter Select chooses CCIR 468 4 A Weighting or C Message filter characteristics for viewing the displayed audio signal Filters are not available in High Res mode NOTE Filtering is automatically disabled when the Audio Spectrum Analyzer is set to High Res ON mode You must reselect the desired filter after returning the spectrum analyzer to High Res OFF mode Cursors Submenu Cursor 1 Cursor 1 On turns on the first solid line cursor On Cursor 2 Cursor 2 On turns on the second dotted line cursor On Cursor n Cursor n Active activates either cursor Once activated a Active cursor may be positioned on the display by rotating the knob Cursor 1 can not be positioned to the right of cursor 2 nor can cursor 2 be positioned to the left of cursor 1 Nearest Nearest Peak positions the active cursor on the nearest signal Peak peak while showing the frequency and signal level of the peak on the numerical display This feature does not seek the highest peak View Harmonics Submenu Har of nn Hz Harmonics of 50 Hz Har of nn Hz permits setting the Harmonic Analyzer fundamental frequency to any frequency in the range press the Har of soft key and turn the knob to the desired frequency You can view seven levels of harmonics from 20 Hz to 20 kHz Harmonics of 50 Hz selects the 50 Hz fundamental frequen cies for display These selection and the Harmonics of 60 Hz choice can help you locate power source fr
45. ection Touch the highlighted source file to select it Rotate the front panel knob to change the audio source file selection if you are using an audio source file other than the system default When you have specified the audio inputs and source files touch the Accept Input soft key If the change is correct touch the Update amp Exit soft key otherwise touch the No Change amp Exit soft key VM700T Option 40 41 42 Audio Measurements User Manual B 9 Appendix B Verification Procedure NOTE If you change audio input and source files and then decide to exit the directory and cancel the change you must press the Accept Input soft key followed by the No Change amp Exit soft key The VM 700T verifies that you want to exit the Source Selection Audio directory and cancel any changes by asking you to touch the No Change amp Exit soft key again Check Level Measurement Accuracy and Flatness Specifications Checked Option 41 Level Accuracy and Flatness B 10 This procedure verifies flatness and measurement accuracy by checking signal levels at specified frequencies NOTE Frequencies and levels checked are not specified in this procedure If the measurement accuracy of certain frequencies and levels is important to your application we recommend that your test procedure include those frequencies and levels Table B 4 lists audio option accuracy and flatness specifications Table B 4 Accuracy and Flatnes
46. ects the ability to accurately measure high signal to noise levels The Audio option Multitone Analyzer provides three types of graphical display m View Levels displays received signal level vs frequency on a near real time basis m View Difference displays interchannel gain and phase differences for the stereo pair m View Distortion and Noise displays the remaining spectrum after energy is removed at frequencies near the multitones this display contains only noise and distortion products Figure 2 12 shows the Multitone Analyzer level versus frequency display VM700T Option 40 41 42 Audio Measurements User Manual 2 22 Operating Basics MULTITONE ANALYZER Ref L 15 95 dBu at 750Hz Range L AUTO Range R AUTO Ref R 15 95 dBu at 750Hz Analyzed signal MTone4 Left Channel dB 80 200 400 800 2k 4k 8k 20k Hz Change Set Input Set Ref Limits Rescale View Range Level OFF Figure 2 12 The Multitone Analyzer level versus frequency display in View Levels mode Data above the graphical display shows the following information m level in dBu of the reference signal used W reference signal frequency m left and right channel input range selected m name of the multitone input signal The menu hierarchy of Multitone Analyzer is shown in Figure 2 13 VM700T Option 40 41 42 Audio Measurements User Manual 2 23 Operating Basics
47. eese een 2 3 Figure 23 The Audio Monitor phase display soundstage format 2 6 Figure 2 4 The Audio Monitor time display 0 c eee eee eee 2 7 Figure 2 5 The Audio Spectrum display 0 0 00 0 000000 2 8 Figure 2 6 The Audio Spectrum menu tree 00 000000 2 9 Figure 2 7 The Audio Spectrum display in High Res mode 2 11 Figure 2 8 The Harmonic Analyzer display showing 60 Hz and its harmoniCs ensi eT ete E eb een 2 12 Figure 2 9 The View Audio Auto Test menu tree 0 0 2 15 Figure 2 10 The View Audio Auto Test text screen display 2 16 Figure 2 11 Typical View Audio Auto Test graph phase display showing upper and lower test limits faint lines onnenn nannaa cece esee 2 19 Figure 2 12 The Multitone Analyzer level versus frequency display in View Levels MOE cb ueesisnd 9exbueeeebepeHREPURREPePRHELSER PS ERU LAE RS E 2 23 Figure 2 13 The Multitone Analyzer menu tree 00 2 24 Figure 2 14 The Multitone Analyzer distortion plus noise components versus frequency display eseeleeeeeeee eee 2 26 Figure 2 15 The Multitone Analyzer cursor display with both cursors acte coL oe x oe t eC An C RW ERN an See a 2 28 Figure 2 16 Orientation of the cable adapter collar 2 31 Figure 2 17 Option 41 Triple Input Audio input connector pin locations 2 31 Figure 2 18 Ferrite forms i
48. elete Create Rename Print Leave File File Directory Figure 1 3 Audio Limit menu choices To modify audio limit file parameters you must do the following tasks W create a new file W select an existing file to be used as a template m name the file you are creating m edit the information in the new file as necessary W accept the edits WB save the new file VM700T Option 40 41 42 Audio Measurements User Manual 1 3 Getting Started 14 Creating an Audio Limit 1 Touch the Create File soft key File The query line the top line of the display asks you to select a file to be used as a template for your new file as shown in Figure 1 4 Please select a file as template EndtoEnd LongHaul MediumHaul NewLimits ShortHaul System Default Satellite In nvram ConfigFiles Audio Limits Files Delete Create Rename Print Leave J File File Director Figure 1 4 Selecting an Audio Limit file to use as a template 2 Touch the appropriate soft key for example System Default 3 The screen displays a keyboard that you can use to type a name for your new file see Figure 1 5 4 Type the new file name 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 _ underline or
49. ement The line may say that it is waiting for either or both triggers audio and video to arrive or that one or the other has arrived and it is waiting for the other Upon receiving both triggers the VM 700T makes the measurement and provides a delay time numerical readout and a graphical display VM700T Option 40 41 42 Audio Measurements User Manual 2 33 Option 41 and Option 42 VM700T Signal Hookup 2 34 The measurement requires both video and audio test signal connections Use one two or all three video input channels The selected channel A B or C on the VM700T is the source for the video part of the measurement but audio signal selection is not automatic With Option 40 you must externally switch the correct audio signal when switching the video measurement source between channels With Option 41 you must correctly configure the Source Selection Audio file to match the video source with the correct audio source Refer to the previous Option 41 information and Configuring the Source Selection Audio file on page 2 29 The audio part of the timing measurement can come in on either the Left or the Right channel input the measurement looks at both channels The first arriving audio signal provides the audio trigger Audio Video Timing Menu Set Input Range Set Input Range enables you to select the range window that most closely matches the amplitude range of the input signal The VM 700T will digitize audio in a 92 dB
50. equency contamina tion VM700T Option 40 41 42 Audio Measurements User Manual 2 13 Operating Basics View Audio Auto Test 2 14 Harmonics Harmonics of 60 Hz selects the 60 Hz fundamental frequen of 60 Hz cies for display These selection and the Harmonics of 50 Hz choice can help you locate power source frequency contamina tion Set Input Set Input Range enables you to select the range window that Range most closely matches the amplitude range of the input signal The VM 700T digitizes an audio signal measured in a selectable 92 dB window over a total range of 132 dB The input ranges of the left and right channels may be configured independently with the Left Range or Right Range soft keys In Auto the range window is adjusted to find the best range for the applied signal level NOTE Use care when selecting AUTO for setting the input range If varying signals such as voice are applied to the Audio option the attenuators constantly switch ranges as they attempt to select an appropriate measurement window for a constantly varying input signal View View Spectrum toggles the display back to the View Spectrum Spectrum application The View Audio Auto Test measurement detects captures and displays Tek ANSI and CCITT Recommendation O 33 automatic audio measurements on the currently selected audio channel Test signals applied must adhere to these quoted standards to be used by the option for valid measurements
51. est signal Peak peak while showing the frequency and signal level of the peak on the numerical display The cursors does not go to the highest peak VM700T Option 40 41 42 Audio Measurements User Manual 2 27 Operating Basics MULTITONE ANALYZER Range L AUTO Range R AUTO Analyzed signal MTone4 DistortiontNoise on Left Ch dBu J A 4 85 d 100 i i i t i i 1 D i 1 t i i i 1 1 105 110 115 d o 5000 10000 15000 20000 Hz Average Off Cursorl 8016 Hz 24 Hz 109 98 dBu Cursor2 11578 Hz 24 Hz 106 00 dBu 3 98 dB Diff Noise Area between cursors 86 87 dBu Nearest Cursor 1 Peak Active Figure 2 15 The Multitone Analyzer cursor display with both cursors active VM700T Option 40 41 42 Audio Measurements User Manual 2 28 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com eS Sa Option 41 and Option 42 This section describes Option 41 operation where it differs from the operation of Option 40 and the use of either option in the AV Time Measurement feature of Option 42 Triple channel input option 41 Configuring Source Selection Audio Option 41 of the VM 700T was introduced to provide an added audio input channel to fill the need for a customer The extra channel input was found to be useful enough that it was released as a standard option for the
52. ft and right inputs and view left or right channel distortion and noise components of the signal see Figure 2 14 Set Input Set Input Range enables you to select the range window that Range most closely matches the amplitude range of the input signal The VM 700T digitizes an audio signal measured in a selectable 92 dB window over a total range of 132 dB The input ranges of the left and right channels may be configured independently with the Left Range or Right Range soft keys In Auto the range window is adjusted to find the best range for the applied signal level NOTE Use care when selecting AUTO for setting the input range If varying signals such as voice are applied to the Audio option the attenuators constantly switch ranges as they attempt to select an appropriate measurement window for a constantly varying input signal Set Ref Set Ref Level selects the signal reference level menu with Level two soft key selections Level at Ref Freq the default and Ref Lvl n dBu Level at Ref Freq shows the signal level at the reference frequency listed Ref Lvl n dBu lets you set the reference level in dBu by rotating the knob The soft key legend displays the level you set Limits Limits ON OFF enables or disables the Multitone signal input ON OFF limits The limits are set in the configuration files during setup of the VM 700T Option 40 for operation NOTE When you disable the audio signal input limits the
53. g Instructions The Audio Video Timing feature of the VM 700T is part of a system that measures the timing difference between audio and video portions of a program that arrive from different transmission paths Use this feature in conjunction with the VITS 200 NTSC Generator and Inserter or the VITS 201 PAL Insertion Generator and the ASG 100 or ASG 140 Audio Signal Generator that is also equipped for the Audio Video Timing measurement Check the operators manuals for your instruments to determine if they support the measurement The generators may be modified if they do not support the measurement Audio Video Timing Audio Delay 22 5 mSec 60 0 40 0 20 0 0 0 20 0 40 0 60 0 mSec l l l l l l l I l 2 0 1 5 1 0 0 5 0 0 0 5 1 0 1 5 2 9 Frames Set Input Active Vertical Rescale Range Video Interval Figure 2 19 The Audio Video Timing display The Audio Video Timing measurement feature on the generators permits synchronization of the video and audio test signals at the sending end of the program The VM700T equipped with Option 40 or Option 41 and Option 42 the Audio Video Timing measurement receives both signals and measures the timing difference to aid in retiming the signals Figure 2 19 shows the VM 700T display for the Audio Video Timing measurement display The error message line above the graph provides information regarding the state of the triggers needed to make a timing measur
54. hannel into the left channel for test sequences that include a crosstalk test sweep signal View L R plots the crosstalk from the left channel into the right channel for test sequences that include a crosstalk test sweep signal Rescale restores the default scaling for the display VM700T Option 40 41 42 Audio Measurements User Manual 2 21 Operating Basics Multitone Analyzer Most audio tests consist of measuring a sine wave audio tone then stepping the frequency and repeating the test The process continues until a measured level versus frequency graph can be assembled and displayed Each audio test typically takes several seconds The technique is accurate and where time is not an issue is the best way to perform an audio test But when only a few seconds are available to perform a complete measurement or for adjusting a processing device or nulling a distortion near real time updates of measurement data are necessary The VM 700T Audio option Multitone Analyzer addresses this problem Instead of measuring a single frequency sine wave the Multitone Analyzer measures a test signal consisting of sine waves at several frequencies From the received multitone signal the Multitone Analyzer produces level versus frequency or distortion plus noise graphs NOTE The maximum amplitude of an individual tone in a multitone signal is lower than it would be if it was the only tone sent This lowered signal to noise ratio aff
55. he Signal Text in the Active Video This procedure is used to place the signal text in the active video 1 Connect a PAL video source so that the VITS 201 is genlocked Ensure that J39 on the VITS 201 is set to 2 3 Open S11 switch 4 and switch 10 Pe gt Press the Function button until a C appears Enter some text such as AV TIME Only one character is needed NOTE The output signal is HIGH during this function 5 Open S11 2 Press the Function button until an F appears Set the Standby INTERNAL test signal as described inside the front cover of the VITS 201 to 0 Black VM700T Option 40 41 42 Audio Measurements User Manual 2 38 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com Option 41 and Option 42 6 Open S11 switch 3 and closed S11 switch 10 7 Connect a special cable between the VITS 201 remote connector and the ASG100 ASG 140 remote connector as shown in Figure 2 23 A switch should be used in line with pin 13 to use as an ENABLE Connect the switch as shown between pin 13 and pin 8 Other standby pages of standby text can be used by grounding pins 4 and 11 See the VITS 201 PAL Insertion Generator User Manual for more details VITS201 Enable Force Standby Pin 13 o ASG100 ASG140 Standby Message Enable Pin12 Timer Pin14 Ground Pin 8 e Figure 2 23 Cabling between the VITS 201 and the ASG 100
56. his manual describes configuring and using the audio measurement options Option 40 Option 41 and Option 42 for the VM700T Video Measurement Set Contents of This Manual This manual consists of the following sections Getting Started introduces the VM 700T audio options by briefly describing the capabilities of each This section also describes the Option 40 signal connections and discusses configuring the option to work with the VM 700T Basic Operation discusses the Option 40 measurements and illustrates its data displays This section also provides general application information and describes the operation and features of Option 41 and Option 42 Remote Commands and Keywords introduces the VM 700T audio option remote commands and keywords and provides examples of their use Appendix A lists the performance specifications and limits for the VM 700T audio options Appendix B provides the procedures for doing a product verification for Option 40 and Option 41 General Information The VM700T audio measurement options expand the power of the VM 700T Video Measurement Set to include comprehensive audio measurement capabili ties Option 40 and Option 41 VM700T Option 40 and Option 41 capabilities include m automated and manual audio measurements m audio spectral analysis with harmonic analyzer W stereo monitoring W real time display of audio parameters m multitone testing VM700T Option 40 41 42 Audio Measurements User Ma
57. ics of 50 Hz 2 13 Harmonics of 60 Hz 2 14 High Res OFF ON 2 10 Index 2 Insertion Gain Error 2 17 K keyboard Setl 1 4 Set2 1 4 keywords 3 5 Group A 3 5 Group B 3 6 Option 40 Group W 3 7 Option 41 Group W 3 7 keywords A list of 3 5 keywords B list of 3 5 keywords form of A group 3 5 keywords form of W group 3 7 L Left Ch Dist N 2 26 Level at Ref Freq 2 25 Level in dB 2 5 Level in Volts 2 5 Level Meter 1 10 Limits ON OFF 2 25 limits changing graphically 1 6 Limits OFF 2 4 Limits ON 2 4 Limits ON OFF 2 25 Lineup Level 1 10 Lissajous Display 1 10 Lissajous phase display 2 6 LOCKED UNLOCKED in Audio Analyzer 2 5 LOG LINEAR scale in Audio Analyzer 2 5 menu structure in Multitone Analyzer 2 23 menu tree Audio Analyzer 2 2 Audio Spectrum 2 9 meter ballistics choices for 1 10 modify audio source file parameters 1 7 Multitone Analyzer purpose 2 22 Multitone Analyzer Main Menu 2 25 Multitone Analyzer Specifications A 5 VM700T Option 40 41 42 Audio Measurements User Manual Index N name list front panel buttons 3 3 Nearest Peak 2 13 2 27 O 0 33 in View Audio Auto Test 2 15 O 33 Test Levels 1 10 Option 40 Verification Procedure B 3 Option 41 Verification Procedure B 10 Option 48 the GPIB interface 3 1 Option differences B 9 P Phase Difference 2 18 Pk Hold ON OFF 2 7 2 8 Placing the Signal in the act
58. in 6 dB b The measurement range specification assumes that the input level is within 6 dB of the 0 33 test level in the audio configuration The actual 0 33 test level range is 6 dBu to 14 dBu The weighting filter is a 15 kHz sharp cutoff low pass filter A 2 VM700T Option 40 41 42 Audio Measurements User Manual Appendix A Audio Option Specifications Audio Analyzer Specifications Table A 3 Frequency and Noise Specifications Measurement Specification Comments Level Maximum Allowable Input 30 dBu 24 5 V rms Resolution 0 1 dB Frequency Range 20 Hz to 20 kHz Accuracy 1 Hz for input gt 60 dBu Resolution 1 Hz for input gt 60 dBu Phase Difference Minimum input level for specified accuracy Phase measurement error 40 dBu 1 for inputs at 40 Hz to 20 kHz 2 for inputs at 40 Hz to 20 kHz Total harmonic distortion amp noise THD N Measurement bandwidth Input level Residual THD4N Maximum measurement Accuracy Channel Separation 33 Hz to 22 kHz 2 20 dBu lt 0 03 70 0 10 of reading 1 digit for harmonics Measurement Window 24 Hz Measurementis taken in the undriven 20 Hz to 350 Hz 96 Hz channel The measurement window follows m the driven channel signal frequency 2350 Hz Constant bandwidth Measurement F ilter Plot Mode Minimum frequency change t2Hz Minimum dwell time 1 sec for input frequencies 500 Hz 500 ms for input frequencies 2 500
59. io Measurements User Manual 3 1 Remote Commands and Keywords Command Format NOTE The following material is an abbreviated explanation of the remote commands It assumes that you understand the principles of remote VM 700T operation and have access to the VM 700T RS 232 Interface Programmer Manual and if applicable the VM700T Option 48 GPIB Interface Programmer Manual The VM700T remote control commands use this form command argument 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 that for serial remote control VM700 is a prompt from the VM 700T which you can change not an input With Option 48 any prompt you see depends on the GPIB controller programming it is not a return from the VM700T Audio Remote Commands execute application Once in communication with the VM 700T the following remote commands can be used with the Audio option 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 VM700 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
60. ive video VITS200 2 36 VITS201 2 38 in the Vertical Interval VITS200 2 35 VITS201 2 37 Plot ON OFF 2 2 Polarity 2 17 R Ref Lvl n dBu 2 25 remote control command format 3 2 Report in Audio 1 10 Rescale 2 4 2 25 Right Ch Dist N 2 26 RS 232C port for remote operations 3 1 S Select Graph 2 2 functions of soft key 2 4 set VM700T Command 3 4 Set Input Range 2 5 2 12 2 14 2 34 set input range 2 25 Set Ref Level 2 25 Settling Time 2 5 show VM700T Command 3 4 Show Text 2 20 show text display 2 16 SNR weighted dB 2 17 soft key VM700T Command 3 4 VM700T Option 40 41 42 Audio Measurements User Manual Source Selection Audio B 9 Source Selection Audio configuring 1 11 Special Setup 2 10 Special Setups 2 2 Specifications A V Timing A 6 Audio Analyzer A 3 Audio Spectrum A 4 Automatic Audio Test A 1 Multitone Analyzer A 5 Stereo Channel Assignment 2 17 Sweep Max Gain 2 17 Sweep Min Gain 2 17 T TEK TEST 95 2 18 Tek Test 93 2 17 Tek test sequence 2 15 Tek Test sequences 2 16 Tek ANSI 2 14 Tektronix Test Automatic Audio Test A 2 template existing file used as 1 3 terminal program 3 1 Test equipment required verification procedures B 1 THD N in dB 2 5 THD N in Percent 2 5 THD at TEST 10 dB 2 20 THD at TEST 15 dB 2 20 THD at TEST Level 2 17 2 20 THD at TEST Level 10 dB 2 17 THD at TEST Level 15 dB 2 17 Total harmonic disto
61. l harmonic distortion and inter channel crosstalk For informa tion on configuring View Audio Auto Test refer to Configuring the Audio Option beginning on page 1 1 VM700T Option 40 41 42 Audio Measurements User Manual 2 16 Operating Basics TEK TEST 93 Insertion Gain Error Sweep Max Gain Sweep Min Gain Measures input audio signal level and compares it with the correct signal value Measures the difference between actual and expected gain Makes a frequency sweep and displays maximum or minimum deviations NOTE If either the Sweep Max gain or the Sweep Min gain exception limits are exceeded both will be flagged with a double and the message Limits Exceeded appears in the View Audio Auto Test Screen display The values displayed will be the max and min sweep gain values but they may not be the limits that were exceeded during the sweep The amplitude and frequency exceptions are displayed graphically in other View Audio Auto Test screens The logging information sent to the serial port also includes the actual value and frequencies of all limit exceptions that occur during the tests Polarity Stereo Channel Assignment SNR weighted dB Max THD N during tone sweep Max THD N at TEST 10 dB Max THD N at TEST 15 dB Max Crosstalk during sweep Checks the polarity of the polarity portion of the test signal to determine if the signal is normal or reversed Checks f
62. les used by the VM 700T for audio measurements are configured in the Audio Limit Files directory and specified in the Audio Source Files directory Likewise the audio source files are configured in the Audio Source Files directory and specified in the Source Selection Audio directory In the Source Selection Audio file you can select an audio source file if you intend to use a source file other than the system default for each of three sources Specifying an Audio Source File To specify an audio source file use the following procedure 1 Touchthe Source Selection Audio soft key 2 Rotate the front panel knob to highlight the source for which you are specifying an audio source file source A B or C NOTE The audio channel can be associated with one of three video inputs Source A B or C However switching the VM 700T from one video input to another during an audio measurement sequence can cause the most recent audio test data to be lost To prevent data loss configure the audio source files in Source Selection Audio to be identical for all video inputs 3 Touch the highlighted source file to select it 4 Rotate the front panel knob to change the audio source file selection 5 When you have selected an audio source file touch the Accept Input soft key 6 Ifthe change is correct touch the Update amp Exit soft key otherwise touch the No Change amp Exit soft key NOTE If you change the audio sou
63. mal reading while a 20 dBu signal yields a worst case reading 2 Check THD N Measurement Accuracy a With 600 output resistance selected connect the outputs of two sine wave generators in parallel to the left channel of the dual female XLR to DB 37 female adapter cable see Figure B 4 To Option 41 Audio Input Connector Figure B 4 Option 41 cable connections for distortion measurement accuracy check B 12 VM700T Option 40 41 42 Audio Measurements User Manual Appendix B Verification Procedure b Setone sine wave generator for a 2 V rms output at 1 KHz Set the second sine wave generator for a 0 02 V 20 mV rms at 3 kHz These two signals add across the termination resistance to produce a 1 kHz signal with a 1 third harmonic distortion d Run the Audio Analyzer measurement and check for a THD N reading of 0 9 to 1 1 e Move the generator signals to the right channel input and repeat step 2 part d Repeat step 2 for channels B and C substitute the appropriate channel when channel A is called for Check Frequency and Phase Measurement Accuracy This procedure requires an accurate frequency generator or a digital counter to set the frequency The phase measurement requires that both channels have the same signal applied Specifications Checked Option 41 Frequency Accuracy and Channel Phase Difference This procedure checks the following parameters Frequency accuracy 1 Hz or 0 01 1
64. mation on how to select and run the Audio Option diagnostics NOTE Performing the following procedures requires the fabrication of non standard adapters and cables These are used to connect a sine wave generator to the VM 700T audio option The following list of test equipment describes the cable ends needed except for the provided female XLR to male mini XLR adapter cable locating the components and fabricating the cables is the responsibility of the user Test Equipment Required The test equipment needed to perform the verification procedures is listed in Table B 1 Test equipment suggestions for use in doing the verification procedure are given in the example column The examples given are based on the test equipment that many customers and the Tektronix service centers have installed for supporting the VM700 family of video measurement sets Substitute test equipment may be used if available Refer to the Minimum Specification column to determine the key specifications needed to verify the accuracy of the VM700T Video Measurement Set Audio option VM700T Option 40 41 42 Audio Measurements User Manual B 1 Appendix B Verification Procedure Table B 1 Test Equipment Required for Verification Procedures Equipment Minimum Specification Purpose Example Sine wave generator Frequency accuracy 30 0196 level flatness 20 Hz to 20 kHz 0 05 dB level accuracy 20 Hz to 20 kHz 0 2 dB residual distortion 0 0
65. n 2 29 Triple channel input option 41 0 eee eee 2 29 Configuring Source Selection Audio 00 00 0000 e eee eee 2 29 Back Panel Audio Connector Pin Assignments 2 30 Audio Signal Interconnection Cable 0 0 0 0 e eee eee 2 31 EMI Reduction Ferrite Choke 0 0 0 0 2 31 Audio Video Timing Option 42 0 00 eee eee eee 2 33 VM700T Audio Video Measurement Operating Instructions 2 33 VM700T Signal Hookup sssseeee I 2 34 VITS 200 and ASG 100 ASG 140 Audio Video Measurement Operating Instructions 0 0 0 0c eee ee 2 35 VITS 201 and ASG 100 ASG 140 Operating Instructions 2 37 Remote Commands and Keywords Command Format ss et seere cece eee teens 3 2 Audio Remote Commands 0 0 002 cece cee eee ee 3 2 execute application yoshi es eo LUE RU EBOC EIE A ES IE 3 2 get keyword channel letter 0 00 00 eee eee ee eee 3 3 Betres llsz a eee ey t Le eset Sed Beh Oe SEE ad od Sng Oe tet ates 3 3 hardkey buttons name eene Wan ei E CRUCE RUE EUR as 3 3 set keyword channel letter valuel value2 esses 3 4 show filename oo PELLUS ue RM RC EIE 3 4 softkey softkey name 0 0 0 hieni E III 3 4 Get and Set Command Keywords slsleseeeeeeeeeee 3 5 Group A Keywords eee Ei m eR pec eden E 3 5 Group B Keywords 0583045 p ee pre bea age bue es 3 5 Group W Keywords
66. nstalled on the signal interconnection cable 2 32 Figure 2 19 The Audio Video Timing display 00 2 33 Figure 2 20 Cabling between the VITS 200 and the ASG 100 ASG 140 for Vertical Interval us the rUESSRURNTULEE NGUIRTOEUS S Ve s 2 36 Figure 2 21 Cabling between the VITS 200 and the ASG100 ASG 140 foractiye Video ores eb oe d hes tia See Cha ee E ENDE 2 37 Figure 2 22 Connecting the VITS 201 and the ASG 100 ASG 140 for Vertical Interval o act EE Ss een Ge rS 2 38 Figure 2 23 Cabling between the VITS 201 and the ASG100 ASG 140 for Active VIMEO cuente CES OLOR OHNE UAI Soa oe AER e x 2 39 Figure B 1 Option 40 cable connections for level accuracy and fl tness CHECK sotie tea ee Ate a i noe Sd P ES PENAS B 4 VM700T Option 40 41 42 Audio Measurements User Manual Table of Contents Figure B 2 Option 40 cable connections for distortion measurement accuracy check 2 ben ee beak HAL eats Bees SO SG GE eS VS B 5 Figure B 3 Option 41 cable connections for level accuracy and Tatnesse clieck ain og neh dda eles dete as iu tebe Ppa ated aint at B 11 Figure B 4 Option 41 cable connections for distortion measurement accutacy Check j oc55 0 Lee abes ue de ee RR sl epe cs B 12 List of Tables Table 2 1 Audio Option 41 Connector Pin Assignments 2 30 Table 3 1 Front Panel Button Names 0 00 00 eese 3 3 Table 3 2 Group A Keywords for Audio Configuration 3
67. nual vii Preface viii Option 42 These options also enable the VM 700T to continuously monitor audio test lines for the presence of a test sequence designed for automated testing the TEK sequence The audio option tests to ANSI standard T1 502 1988 EIA TIA 250 C or CCITT Recommendation O 33 The audio measurements results obtained using automatic monitoring can be included in the VM 700T Auto Mode video measurements display with the time and date of the last sequence received Timed reports and the logging of results can be performed automatically Also a file in the VM 700T Measurement Results directory is updated each time an audio auto test sequence is received and measured Option 40 has two stereo input channels with mini XLR input connectors Option 41 provides for three stereo input channels connected through a male DB 37 connector A female DB 37 connector is provided with Option 41 to use for fabricating the interconnecting cable that applies the signals to be measured to the triple input of the VM 700T Either Option 40 or Option 41 may be installed in the VM 700T not both The Audio Video Timing measurement option Option 42 of the VM 700T is part of a system that measures the timing difference between audio and video portions of a program that arrive from different transmission paths This feature is used in conjunction with the VITS 200 NTSC VITS Inserter or VITS 201 PAL Insertion Generator and the ASG100 or ASG140
68. on describes using the four measurements of Audio Option 40 41 Audio Analyzer Audio Monitor Audio Spectrum and View Audio Auto Test You may display the Audio option measurements by pressing the Measure button and touching the Audio soft key Select an Audio option measurement by touching its soft key Figure 2 1 shows the Audio Analyzer display The Audio Analyzer measures and displays two channels of audio signal The display plots frequency on the x axis and level in either volts or dBu depending on your selection on the y axis Audio signal input limits may be selected at configuration and enabled or disabled in the main Audio Analyzer menu Limits ON OFF When enabled the selected limits are shown in the displays AUDIO ANALYZER Input Number 1 Frequency Level Level Diff 0 002 dB 20 000 kHz 0 30 dBu 20 000 kHz 0 29 dBu a Phase Diff 0 44 deg Left channel 8Bu 0 0 0 a BRON Right Channel dBu o Mon enm i 0 0 0 ITETTEFETE FTT ERRESTRRTRINM a BRO Range L 10 dBu Range R 10 dBu Plot On Views Locked EN PN EX P EE El piod EN PN EX P EE El Figure 2 1 The Audio Analyzer display 0 33 test sequence VM700T Option 40 41 42 Audio Measurements User Manual 2 1 Operating Basics Other features of the Audio Analyzer include the following displays m Linear or log frequency display m Display scales for x and y axes may be moved
69. 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 After typing the name touch Done to complete the creation of the file If you do not want to create the new file press Cancel to quit the process The VM 700T now displays the new file containing the audio limits from the file you selected as the template You can modify the parameters in this file VM700T Option 40 41 42 Audio Measurements User Manual Getting Started 1 6 Editing an Audio Limit Text Parameter Change any audio limit text parameter using the following procedure 1 Rotate the knob to highlight the line containing the parameter you wish to change This includes the title line in the configuration file Use a descriptive file name for help in identifying it later 2 Select the parameter you want to change by touching it 3 Rotate the knob to increase or decrease the parameter value 4 Touchthe Accept Input soft key to accept the change NOTE If you change a parameter and then decide you don t want to keep the change press the No Change amp Exit soft key The VM 700T verifies that you want to exit without changing anything by asking you to touch the No Change amp
70. only for the Graph Levels selection it disappears when Graph THD N or Graph Ch Sep are selected Figure 2 2 The Audio Analyzer menu tree VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics 2 4 Limits ON OFF Limits ON displays the limits levels set up in the configure files and measures against those limits Limits OFF turns off the limits levels CAUTION When you disable the audio signal input limits the audio input signal is not checked against the limits that may have been selected during configura tion Rescale Rescales the display to its default values Select Graph Submenu Graph Levels Graph Levels mode measures and displays frequency level and phase differences NOTE In Graph Levels mode level difference limits are displayed in dB but not in volts Graph THD N Graph THD N mode measures and displays frequency level THD N and phase differences Graph Ch Sep Graph Channel Separation mode measures THD N only on the driven higher level channel Graph Separation mode also let you view the incoming signal s level and phase differences View Diff View Diff displays the level difference between the left and right channels in dBu or volts and their phase difference in degrees This selection is available only when you select the Graph Levels mode View Left View Left displays the left channel individually The vertical scale of the display increases to fill the dis
71. ons 1 2 3 4 Select manual mode Select 10 kHz frequency Select 10 dB output level Select On Line red LED is on Checkout Grounding pin 1 of the remote connector turns off the audio output VITS 201 Instructions This procedure is used to place the signal text in the vertical interval 1 2 3 Connect a PAL video source so that the VITS 201 is genlocked Open S11 switch 4 and switch 10 Press the Function button six times until a C appears Enter some text in the vertical interval like AV TIME Only one character is needed VM700T Option 40 41 42 Audio Measurements User Manual 2 37 Option 41 and Option 42 NOTE The output signal is HIGH during this function 4 Close switch 10 5 Connect a special cable between the VITS 201 remote connector and the ASG 100 remote connector as shown in Figure 2 22 VITS201 ASG100 ASG140 Figure 2 22 Connecting the VITS 201 and the ASG 100 ASG 140 for Vertical Interval Checkout When the VITS 201 is in the power up Line Selection mode and is genlocked the signal at pin 14 of the remote connector will be a TTL low voltage for 4 5 seconds and then high for 0 5 seconds The signal transitions from low to high at line 1 field 1 When the TTL signal is high the audio output is ON but the text inserted by the VITS 201 does not become visible until line 10 This delay time is subtracted out of the VM700T A V Timing measurement Placing t
72. or Normal or Swapped depending on which channel receives the test sequence preamble The left channel normally receives the test sequence preamble Measures the CCIR quasi peak weighted signal to noise ratio Measures the maximum total harmonic distortion plus noise in percent during the THD at TEST Level sweep portion of the test sequence Measures the maximum total harmonic distortion plus noise in percent during the THD at TEST Level 10 dB sweep portion of the test sequence Measures the maximum total harmonic distortion plus noise in percent during the THD at TEST Level 15 dB sweep portion of the test sequence Measures the maximum channel to channel crosstalk in dB during the crosstalk portion of the test sequence VM700T Option 40 41 42 Audio Measurements User Manual 2 17 Operating Basics Gain Measures the maximum gain difference in dB between left Difference and right channels over the test frequency sweep Phase Measures the maximum phase difference in degrees between Difference left and right channels over the test frequency sweep The phase difference is referenced to the left channel so the phase difference reading may be negative or positive TEK TEST 95 The Tek 95 sequence provides a signal to measure ANSI Crosstalk The View Audio Test results for Tektronix Program 95 reports the following measure ments m Insertion Gain Error dB m Sweep Max Gain dB m Sweep Min Gain dB m
73. or expanded about any point on the screen W Left right difference or left and right displays W User adjustable point plot condition characteristics Numerical displays in the upper part of the display provide the following readouts m Frequency level and total harmonic distortion and noise information m Input channel level differences m Input channel phase differences NOTE If selected the Audio Analyzer is active If an input signal is not being received the readouts will be indicating noise levels not previously received signal levels The following paragraphs describe the soft key functions of the Audio Analyzer Figure 2 2 shows the Audio Analyzer menu structure Audio Analyzer Main Menu Select Select Graph selects the type of graphing used for the display Graph Special Special Setups accesses two other choices Set Input Range Setups and Settling Time Change Change Scales lets you change scales on the Level and THD Scales N displays and change the frequency scale between log and linear Plot Plot ON OFF enables or disables the plotting of an input signal ON OFF When the plot is disabled OFF the display retains any information previously plotted Erase Plot Erase Plot clears the plot in preparation for new data VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics
74. ource file as a source file for one or all of the channels A B or C as needed for your measure ments Configuring Procedure Begin configuration of the Audio option by pressing the Configure button The screen displays a memory use indicator information about instrument option versions and four soft keys touch screen buttons See Figure 1 1 Press the Configure Files soft key to begin audio configuration VM700T Option 40 41 42 Audio Measurements User Manual 1 1 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com Getting Started Non volatile memory used 52416 bytes free 995904 bytes used free 55 95 VM700T Video Measurement Set Xxxxxx Xxxxx 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 Configure Function Option Time Files Keys Key Figure 1 1 The Configure menu The screen now displays a series of soft key options in a window see Figure 1 2 Scroll the window to view all the menu choices by turning the front panel knob The following topics describe the procedure for configuring the VM700T Audio option
75. ove the input from the generators to the right channel and repeat step 2 part d Check Frequency and Phase Measurement Accuracy This procedure requires an accurate frequency sine wave generator or a digital counter to accurately set the frequency The phase measurement requires that both channels have the same signal applied through equal length cables Specifications Checked This procedure checks the following parameters m Frequency accuracy 1 Hz or 0 0146 1 digit whichever is worse for inputs of 60 dBu or greater in the frequency range of 20 Hz to 20 kHz m Channel phase difference 1 for inputs of 40 Hz to 20 kHz 2 for inputs of 20 Hz to 40 Hz at a level of 40 dBu or greater Option 40 Frequency 1 Connect the sine wave generator output to both the left and right inputs of Accuracy and Channel the Audio board see Figure B 1 PRASE EMI Tence 2 Set the sine wave generator for a frequency and amplitude in the specified frequency and amplitude range of the Audio option 20 Hz to 20 kHz amplitude of 60 dBu or greater VM700T Option 40 41 42 Audio Measurements User Manual B 6 Appendix B Verification Procedure NOTE Use a test signal level of at least 60 dBu and test at least 10 frequencies over the entire range Tested frequencies should include the specification limits 20 Hz 20 kHz and the 40 Hz breakpoint Example frequencies to test might also include the following 100 Hz 200 Hz 1 kH
76. ower Total TEST 10 dB to limit TEST 14 dB Frequency breaks BCSU Channel separation Upper Total TEST 10 dB to limit TEST 14 dB Upper limit BCTF Crosstalk plus noise Total TEST H10 dB to Frequency breaks TEST 14 dB Upper limit BCTL Crosstalk plus noise Upper BING Insertion gain Limit BCTU Crosstalk plus noise Upper BSNR Signal to noise ratio Limit BGDF Stereo gain difference BSPF Stereo phase difference Frequency breaks Frequency breaks BGDL Stereo gain difference Lower BSPL Stereo phase difference Lower limit limit BGDU Stereo gain difference Upper BSPU Stereo phase difference Upper 3 6 limit limit VM700T Option 40 41 42 Audio Measurements User Manual Remote Commands and Keywords Group W Keywords Group W keywords report on or set the active video source selection files Get commands used with the W keywords have the following form get keyword Set commands used with the W keywords have the following form set keyword lt file name gt Table 3 4 lists the Group W keywords for Option 40 and their meanings Table 3 4 Option 40 Group W Keywords for Audio Source Selection Description Keyword Description Keyword WACA Source A Audio Config F ile WACC Source C Audio Config File WACB Source B Audio Config F ile The Option 41 Group A and Group B keywords are the same as those for Option 40 Table 3 2 and Table 3 3 There are three additional Group W keywords for Option 41 Table 3 5 lists the Group
77. pecifications Table A 9 Multitone Analyzer Measurement Specifications Cont Description Minimum Amplitude of R eference Tone for Multitone Recognition Input Range Window m o O UJ FY AUTO RANGE Minimum Multitone Recognition Time first time Measurement Update Rate After Recogni tion Maximum Frequency Error for M ultitone Recognition Level Measurement Accuracy Frequency Measurement Accuracy Specification Comments 10 dBu 20 dBu 30 dBu 40 dBu 50 dBu 50 dBu 1 second 5 readings per second Within 10 of reference frequency Same as Audio Analyzer Same as Audio Analyzer A V Timing Specifications Option 42 Table A 10 Audio Video Timing Measurement Specifications Characteristic Performance Requirement Audio Amplitude Window Audio Amplitude Range Timing Range Timing Accuracy 92 dB 102 dB to 30 dB in five ranges 65 ms 1 ms A 6 VM700T Option 40 41 42 Audio Measurements User Manual DIE SS Appendix B Verification Procedures The procedures in this section are designed to verify the operation of the VM700T Video Measurement Set Audio Option 40 and Audio Option 41 Before performing these procedures we recommend that you run the audio option diagnostics to ensure that the Audio Processor and Audio Analog boards are working properly Refer to the VM700T Option 01 NTSC amp Option 11 PAL User Manual or the VM700T Video Measurement Set Service Manual for infor
78. play area View Right View Right displays the right channel individually The vertical scale of the display increases to fill the display area View L amp R View L amp R permits viewing both channel is the same display The vertical scale of each channel is reduced to fit the two channels into the display area VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics Special Setups Submenu Set Input Range Set Input Range enables you to select the range window that most closely matches the amplitude range of the input signal The VM 700T digitizes an audio signal measured in a selectable 92 dB window over a total range of 132 dB The input ranges of the left and right channels may be configured independently with the Left Range or Right Range soft keys In Auto the range window is adjusted to find the best range for the applied signal level NOTE Use care when selecting AUTO for setting the input range If varying signals such as voice are applied to the Audio option the attenuators constantly switch ranges as they attempt to select an appropriate measurement window for a constantly varying input signal Settling Time Settling Time displays the settling time configuration menu and directions for its use The conditions that may be changed are frequency amplitude amplitude threshold value threshold value dwell time and percent frequency change Touch the Default Settings soft key to return the se
79. pply a 120 Hz input to the Audio option at amplitudes 2 20 dBu for example 18 8 2 12 dBu and verify that the level accuracy is 0 1 dB 5 Select at least 6 frequencies and 10 amplitudes over the listed range to test The frequencies and amplitudes you select must be in the ranges listed in Table B 2 use a signal amplitude level of 70 dBu to test for worst case Table B 3 shows an example selection of test frequencies and amplitudes Table B 3 Example Test Signals for Level and Flatness Test Frequency Amplitudes 30 Hz 10 dBu 21 dBu 40 dBu 49 dBu 100 Hz 5 dBu 55 dBu 59 dBu 1 kHz 61 dBu 65 dBu 70 dBu 5 kHz 12 kHz 20 kHz VM700T Option 40 41 42 Audio Measurements User Manual B 4 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com Appendix B Verification Procedure 6 Setthe sine wave generator for each of the frequencies and amplitudes you have selected to test 7 Ateach frequency check that the measured level is accurate to the limits shown record the level for each frequency 8 Verify that any differences between the measured levels recorded for each frequency are within the flatness specification given in Table B 2 Check Distortion and Distortion Measurement Accuracy This procedure verifies that residual THD N is 0 03 or less and then checks the THD N accuracy of the audio option by reading
80. priate range selection Flatness t 0 1 dB t 0 1 dB t 0 1 dB t 0 1 dB VM700T Option 40 41 42 Audio Measurements User Manual Appendix A Audio Option Specifications Table A 7 Harmonic Analyzer Measurement Specifications Description Specification Comments Highest Fundamental Frequency 9999 Hz Harmonics up to the 20 kHz measurement bandwidth are displayed Measurement Update Rate 6 readings per second View Harmonic Measurement Window 24 Hz All signal energy within the view window is measured Table A 8 Miscellaneous Specifications Description Specification Channel separation crosstalk gt 100 dB a 20 Hz to 20 kHz Input connectors 2 miniature XLR Switchcraft TY 3F require Switchcraft TA3M miniature XLR plug Two mini XLR to XLR female adapters and two mini XLR male plugs are supplied Input impedance 50 kO balanced differential a Noise limited source impedance for both channels is lt 600 Q Multitone Analyzer Specifications Table A 9 Multitone Analyzer Measurement Specifications Description Specification Level of Individual Tones R elative to Multitone RMS Level Multitone 1 19 9 dB Multitone 2 18 9 dB Multitone 3 13 8 dB Multitone 4 15 9 dB Reference Frequency for Multitone Recognition Multitone 1 422Hz Multitone 2 562 Hz Multitone 3 656 Hz Multitone 4 750 Hz Comments VM700T Option 40 41 42 Audio Measurements User Manual A 5 Appendix A Audio Option S
81. r channel A insertion gain from their previous values to 0 5 and 0 5 The show command returns the contents of the specified filename The default path is the Measurement Results directory Other files can be specified with a full pathname or a path relative to the Measurement Results directory Example VM700T gt show nvramO ConfigFiles Source Selection Audio The default file for audio sources Channel A Audio Source xmiter Channel B Audio Source switcher Channel C Audio Source System Default The softkey command soft key used as one word indicates the press and release of a specified soft key such as Cursors Using the softkey command is equivalent to entering softpress and softrelease however in general softkey should be used instead of these commands Example VM700T gt 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 VM700T Option 40 41 42 Audio Measurements User Manual Remote Commands and Keywords For soft keys that perform toggle operations such as ON OFF the soft key 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
82. rce file and then decide to exit the directory and cancel the change you must press the Accept Input soft key followed by the No Change amp Exit soft key The VM 700T verifies that you want to exit the Source Selection Audio directory and cancel any changes by asking you to touch the No Change amp Exit soft key again VM700T Option 40 41 42 Audio Measurements User Manual 1 11 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com Getting Started Connecting to a Source Refer to Option 41 and Option 42 beginning on page 2 29 for connecting Option 41 inputs to a signal source The VM 700T Audio option is supplied with two male mini XLR to female XLR adapter cables wired as shown in Figure 1 7 The mini XLR ends of these cables connect the Audio option to an appropriate audio signal source O ae Female XLR to male mini XLR adapter cable Figure 1 7 Cables and connectors supplied with Audio Option 40 Input Connector Pin Pin assignments for the Option 40 mini XLR connectors are shown in Figure Assignments 1 8 These connectors are accessed at the VM 700T rear panel LEFT SON RIGHT e E C Figure 1 8 Option 40 connectors and pin assignments VM700T Option 40 41 42 Audio Measurements User Manual 1 12 i 4 Operating Basics i 4 Operating Basics Audio Analyzer This secti
83. rsors on 2 13 D DB 37 mating connector 2 31 Dead Air Alarm 1 10 default in Settling Time display 2 5 in Audio Spectrum averaging 2 10 resolution in Audio Spectrum display 2 10 delete audio limit file 1 7 Display Phase 2 7 display options in View Audio Auto Test 2 20 Display Time 2 8 displaying test signals View Audio Auto Test 2 19 Index 1 Index E Erase Plot 2 2 Error Reporting 1 10 execute VM700T Command 3 2 External Termination 1 10 F ferrite forms for EMI reduction 2 31 files rules for naming 1 4 Filter Select 2 13 format of commands 3 2 Freq LOG LINEAR 2 5 frequency sweeps displaying 2 19 G Gain Difference 2 18 get VM700T Command 3 3 Get Set Keywords A Group Audio Configuration 3 5 W Group Audio Source Selection 3 7 getresults VM700T Command 3 3 GPIB parallel port 3 1 Graph Channel Separation 2 4 Graph Crosstalk 2 20 Graph Levels 2 4 2 20 Graph Levels test display in View Audio Auto Test 2 20 Graph Phase 2 20 Graph Phase test display in View Audio Auto Test 2 20 Graph THD 2 20 test display in View Audio Auto Test 2 20 Graph THD N 2 4 graphic display View Audio Auto Test 2 19 graphical display in Multitone Analyzer 2 22 graphical displays audio limit descriptions 1 6 Group A Keywords 3 5 Group B Keywords 3 6 H hardkey VM700T Command 3 3 Harmonic Analyzer purpose 2 13 harmonics frequency selection 2 13 Harmon
84. rtion noise at Test 10 dB 2 17 at Test 15 dB 2 17 during sweep 2 17 Triple channel input 2 29 V Verification Procedure Option 40 B 3 Option 41 B 10 Test Equipment B 1 Verification Procedures B 1 Vertical Interval 2 34 vertical interval VITS200 2 35 VITS201 2 37 View Audio Auto Test 2 14 View Diff 2 4 2 26 Index 3 Index View Difference VM700 prompt 3 2 in Audio analyzer 2 4 VM700A Signal Hookup 2 33 in Audio analyzer 2 20 VM700T Commands View Harmonics 2 11 execute 3 2 view harmonics 2 13 get 3 3 View L R 221 getresults 3 3 View L amp R 2 4 set 3 4 View Left 2 4 show 3 4 View Levels 2 26 soft key 3 4 View R L 2 21 VMT for remote applications 3 1 View Right 2 4 View Spectrum 2 14 Views LOCKED UNLOCKED 2 5 W Views LOCKED UNLOCKED 2 5 VITS200 Checkout 2 36 W group keywords 3 7 VM700T Option 40 41 42 Audio Measurements User Manual Index 4 Test Equipment Depot 800 517 8431 99 Washington Street Melrose MA 02176 FAX 781 665 0780 TestEquipmentDepot com
85. s Specifications Accuracy Frequency Range Level Range includes flatness Flatness 20 40 Hz gt 20 dBu 0 3 0 2 dB 0 1 0 2 dB 20 dBu to 50 dBu 0 4 0 3 dB 0 1 0 2 dB 50 dBu to 60 dBu 0 6 0 5 dB 0 2 0 3 dB 60 dBu to 70 dBu 1 0cB 0 4 0 5 dB 40 Hz 20 kHz gt 20 dBu 0 2 dB 0 1 dB 20 dBu to 50 dBu 0 3 dB 0 1 dB 50 dBu to 60 dBu 0 5 dB 0 2 dB 60 dBu to 70 dBu 1 0 dB 0 4 dB 3 Leveldifference between channels is 0 2 dB at levels of 50 dBu and greater 1 Power on the VM 700T and associated test equipment and let them warm up for 20 minutes 2 Connect the sine wave generator to the Option 41 audio input connector as in Figure B 3 3 Press the Measure hard key select Audio and run the audio analyzer measurement VM700T Option 40 41 42 Audio Measurements User Manual Appendix B Verification Procedure To Option 41 Audio Input Connector Figure B 3 Option 41 cable connections for level accuracy and flatness check 4 Using a known accurate sine wave generator or one verified with an accurate AC voltmeter apply a 120 Hz input to the Audio option at amplitudes 2 20 dBu for example 18 8 2 and 12 dBu and verify that the level accuracy is 0 1 dB 5 Select at least 6 frequencies and 10 amplitudes to test The frequencies and amplitudes you select must be in the ranges listed in Table B 2 use a signal amplitude level
86. ssumes insertion gain is within 6 dB b The measurement range specification assumes that the input level is within 6 dB of the 0 33 test level in the audio configuration The actual 0 33 test level range is 6 dBu to 14 dBu c The value for other test levels can be calculated from the formula 60 Test Level d Measured with Quasi Peak response as per CCIR 468 4 recommendation The measurement range can be determined from the formula 70 Test Level Weighting filter as per CCIR 468 4 recommendation VM700T Option 40 41 42 Audio Measurements User Manual A 1 Appendix A Audio Option Specifications Table A 2 Tektronix Automatic Audio Test Measurement Specifications Measurement Range Accuracy Includes Flatness Insertion Gain Error 6 dB 0 2 dB Sweep Gain Min and Max 12 dB 0 1 dB THD N lt 0 03 to 70 10 1 digit Crosstalk into channel 1 dB Test Level 6 dBu lt 66 dB to 0 dB 0 dBu lt 60 dB to 0 dB 6 dBu lt 54 dB to 0dB SNR weighted 2 dB Test Level 6 dBu 10 dB to gt 90 dB 0 dBu 10 dB to gt 90 dB 6 dBu 10 dB to gt 84 dB ANSI Crosstalk into channel P 0 to 10 dB 0 2dB ANSI SNR weighted 2 dB Test Level 6 dBu 10 dB to gt 90 dB 0 dBu 10 dB to gt 90 dB 6 dBu 10 dB to gt 84 dB Max Compandor Error rise fall 6 dB 0 2 dB Gain Difference 12 dB 0 2 dB Phase Difference 180 to 180 il a Assumes insertion gain is with
87. tandard GPIB cable and a properly configured GPIB controller with a controller program to handle the VM700T For information about configuring the VM 700T serial ports for remote opera tion refer to 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 If your VM 700T has Option 48 the GPIB interface installed additional information on remote operation using GPIB is found in the VM 700T GPIB Option 48 Programmer Manual Operating the VM700T from a remote location includes the following capabili ties m making a specific manual measurement or Auto mode series of measure ments W executing and interrupting a function Function Key m temporarily changing the configuration of a channel s limit files selected measurement files and measurement location files W setting the printer type and port for each type of output Copy Report and Log and specifying an End of File character for printer output The remote commands used with the Audio option functions are the same as those used for other VM 700T functions 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 refer to the VM 700T RS 232 Interface Programmer Manual VM700T Option 40 41 42 Aud
88. ting ALIM Audio Limit File AEXT External termination ALIS Lissajous display AHPT Audio Printout Title ARIA Report in Auto Group B keywords report on or set the measurement limits for Audio Auto mode measurements These keywords can only be used on a VM700T equipped with either the Option 40 or the Option 41 Audio Option VM700T Option 40 41 42 Audio Measurements User Manual Remote Commands and Keywords Get commands used with Group B keywords have the following form get keyword lt channel letter gt Set commands used with Group B keywords have the following form set keyword lt channel letter gt argl argn where lt argl gt lt argn gt are text strings separated by spaces that define the limits associated with the keyword Table 3 3 lists the keywords in Group B and their meanings Table 3 3 Group B Keywords for Audio Source Selection Keyword Description Keyword Description BARF Amplitude Response BHHF Total above TEST414 dB Frequency breaks Frequency breaks BARL Amplitude Response Lower BHHL Total above TEST414 dB limit Upper limit BARU Amplitude Response Upper BHHU Total above TEST 14 dB limit Upper limit BCEF Compander error fall BHLF THD N up to TEST49 dB Frequency breaks BCER Compander error rise Total up to TEST49 dB Upper limit BCSF Channel separation Total up to TEST49 dB Upper Frequency breaks limit BCSL Channel separation L
89. ts soft key The VM 700T begins the deletion process 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 Configuring the Touch the Audio Source Files soft key to enter the Audio Source Files Audio Source Files directory The screen displays the audio source files You can select and press a soft key to display the parameters in a file but the parameters in the system files can not be modified To modify file parameters you must do the following tasks VM700T Option 40 41 42 Audio Measurements User Manual Getting Started 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 necessary accept the edits If the system default audio source file is acceptable the VM 700T will use this file as it performs audio measurements if it is the selected file If you must modify the audio source file read the following paragraphs Editing the Audio Source File To modify the Audio Source file follow this procedure 1 Touch the Create File soft key The query line the top line of the display as seen in Figure 1 6 asks you to select the file to be used as a template for your new file Please select a file as template NewSource System Default
90. ttings to default values Change Scales Submenu Level in Volts Level in Volts sets the level readout and the vertical scale of the display to voltage units Level in dBu Level in dB sets the level readout and the vertical scale of the display to decibel units THD N THD Nin Percent sets the total harmonic distortion plus in Percent noise readout in percentage THD N THD N in dB sets the total harmonic distortion plus noise in dB readout in decibel units Frequency Freq LOG LINEAR toggles between linear or logarithmic LOG LINEAR frequency display Views Views LOCKED UNLOCKED allows you to unlock the left and LOCKED right channel display scales for independent adjustment or lock UNLOCKED them together for concurrent adjustment VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics Audio Monitor The Audio Monitor measurement displays the audio levels and phase relation ships of a two channel audio signal Figure 2 3 shows the Audio Monitor phase display 9 dB 4 dBu R dB L R Display Phase Figure 2 3 The Audio Monitor phase display soundstage format The phase display plots audio input signals in a Lissajous phase display This display may be configured to show the signals in either soundstage the default or X Y oscilloscope format The display also provides a bar graph of left channel right channel and left plus right channel sound levels The scales of the bar graph displa
91. u display The Harmonic Analyzer is a useful tool for locating frequency contamination caused by signals with fundamental frequencies in the 35 Hz to 10 kHz range Rescale Rescale returns the display scaling to its default values VM700T Option 40 41 42 Audio Measurements User Manual 2 11 Operating Basics 2 12 HARMONIC ANALYZER Input Number 1 Range L 10 dBu Range R 10 dBu Fundamental Frequency 60 Hz Level dBu 2 3 4 5 6 7 x Fundamental Harmonics View of 50 Hz Spectrum Set Input Range Figure 2 8 The Harmonic Analyzer display showing 60 Hz and its harmonics Special Setup Submenu Set Input Set Input Range enables you to select the range window that Range most closely matches the amplitude range of the input signal The VM 700T digitizes an audio signal measured in a selectable 92 dB window over a total range of 132 dB The input ranges of the left and right channels may be configured independently with the Left Range or Right Range soft keys In Auto the range window is adjusted to find the best range for the applied signal level NOTE Use care when selecting AUTO for setting the input range If varying signals such as voice are applied to the Audio option the attenuators constantly switch ranges as they attempt to select an appropriate measurement window for a constantly varying input signal VM700T Option 40 41 42 Audio Measurements User Manual Operating Basics Filter Sel
92. video 1 Connecta NTSC video source so that the VITS 200 is genlocked 2 From the front panel select STANDBY MODE TO 0 BLACK ENABLE STANDBY MODE 3 Input the standby message you intend to use for example AV TIME 4 Connect a special cable between the VITS 200 remote connector and the ASG100 ASG 140 remote connector as shown in Figure 2 21 Checkout When the VITS 200 is genlocked the signal at the remote connector pin 20 will be a TTL HIGH voltage for 4 5 seconds and then LOW for 0 5 seconds The signal transitions from high to low at line 1 field 1 The audio output is turned ON at this time but the text inserted by the VITS 200 does not appear until the active video This means that the audio leads the video change The VM 700T Audio Video Timing measurement removes this delay time before presenting the measured time difference VM700T Option 40 41 42 Audio Measurements User Manual Option 41 and Option 42 VITS200 Standby Message Enable Timer ASG100 ASG140 Force Standby Remote Enable Ground Figure 2 21 Cabling between the VITS 200 and the ASG 100 ASG 140 for active video VITS 201 and This custom modification turns the vertical interval text of the VITS 201 PAL ASG 100 ASG 140 Insertion Generator and the output of the ASG100 or ASG140 Audio Generator Operating Instructions on and off at the same instant in time to provide synchronization between the video and audio ASG 100 Instructi
93. window within a total input range of 132 dB The input ranges of the left and right channels may be configured independently with the Left Range or Right Range soft keys There are five input range windows range A 62 to 30 dBu range B 72 to 20 dBu range C 82 to 10 dBu range D 92 to OdBu range E 102 to 10 dBu Rescale Rescale returns the display scaling to its default values Vertical Interval Vertical Interval triggers the video at line 13 This selection is used in a system that places the test signal from the VITS 200 VITS 201 in the vertical blanking interval Active Video Active Video triggers in the active video line 45 for the VITS 200 and line 38 for the VITS 201 This selection is used when working with a CODEC system that does not transmit signals in the vertical blanking interval NOTE The VITS 200 or VITS 201 must be configured correctly to place the test signal in the active video VM700T Option 40 41 42 Audio Measurements User Manual Option 41 and Option 42 VITS 200 and The Video Audio Synchronization custom modification turns the test signal text ASG100 ASG140 ofthe VITS 200 Generator and Inserter and the output of the ASG 100 or Audio Video Measurement ASG 140 Audio Generator on and off at the same instant in time Operating Instructions ASG 100 ASG 140 Instructions 1 Select manual mode 2 Set frequency for 10 kHz 3 Set output level to 10 dB 4 Select On Line Red LE
94. x Program 93 Expected TEST level 0 dBu Source TEK1 Violated Limits Left Right Lower Upper Insertion Gain Error dB Sweep Max Gain dB 0 04 0 04 Sweep Min Gain dB 0 07 0 07 Polarity Normal Normal Stereo Channel Assignment Normal Normal SNR weighted dB 96 95 95 82 Max THD N during tone sweep 0 016 0 019 Max THD N at TEST 10 dB 0 016 0 018 Max THD N At TEST 15 dB 0 016 0 018 Gain Difference dB 0 00 Phase Difference deg 0 01 Show Graph Graph Graph Graph Text Levels Phase THD Crosstalk Figure 2 10 The View Audio Auto Test text screen display Option 40 and Option 41 recognize CCITT recommended test sequences 0 33 00 0 33 01 0 33 02 O33 03 O 33 04 and O 33 05 They also recognize Tek Test sequences Tek 90 Tek 91 Tek 92 Tek 93 Tek 94 and Tek 95 See the ASG 100 Operator s manual or the ASG 140 Instruction manual for a description of the test sequences The information in the show text display changes to show the actual measurements made on received automatic test sequences The following measurements are those included in Tektronix Program 93 Other test programs will display the measurements done during their sequences Configuration options for audio limits accessible in the Configure Files directory can be set to provide alarms that trigger on audio limit data These configurable audio limits include signal to noise ratio insertion gain gain differential tota
95. y axis You can configure the audio input signal level with the Set Input Range soft key see the Set Input Range explanation on page 2 12 for more information Figure 2 6 shows the menu tree for the Audio Spectrum measurement functions Audio Spectrum Average Special Change Cursors High Res View Resak Num n Setup Channel OFF ON Harmonics Touch Softkey then turn knob toset n Cursor 1 Cursor 2 Cursor 1 Cursor 2 Touch Softkey On On Active Active to move Cursor Set Input Filter Range Selection yos CCIR A C 468 4 Weighting Message Set Input Harmonics Harmonics Har of View Range of 60 Hz of 50 Hz nn Hz Spectrum View Spectrum and View Harmonics toggles between the Left a Right alf AUTO two display types Range A E Range A E Range api itizing window choices are displayed under Set Input Range with a choice of five windows as follows The VM700T will digitize audio in a 92 dB window within a total input range of 132 dB There are five input range windows range A 62 to 30d u range B 72 to 20 dBu range C 82 to 10 dBu range D 92 to 0 dBu range E 102 to 10 dBu Figure 2 6 The Audio Spectrum menu tree
96. y may be configured for Nordic PPM or DIN 45406 dB or VU units For information on configuring the phase display see Configuring the Audio Option beginning on page 1 1 The VM 700T Configuration directory allows you to configure these Audio Monitor functions m Level meter scales DIN 45406 or Nordic ppm dB or VU m equivalent dBu setting for 0 dB scale readout m type of Lissajous display soundstage or x y oscilloscope VM700T Option 40 41 42 Audio Measurements User Manual 2 6 Operating Basics For information on configuring the Audio Monitor display see Configuring the Audio Option beginning on page 1 1 Audio Monitor Phase Display Menu Display Display Phase switches the display to a format that shows the Phase two input signal waveforms in voltage and time AGC AGC OFF ON adjusts the gain of the displayed signal to better OFF ON reveal the shape and pattern of low level signal when AGC is on Pk Hold Pk Hold ON OFF retains peak signal levels for a few seconds ON OFF when on the peak hold function is on Audio Monitor Time The Audio Monitor time display see Figure 2 4 plots the left and right channel Display signal voltage levels on the y axis and time on the x axis Left Channel volts 9 dB 4 dBu R dB L R ETRTERETEERTRYRTRTEIRERERTRYRERTRYRRERR TERR TERRE RTRTRTRERIRIRERTRERERTRENTRERE 0 0 0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 milliseconds Right Channel volts 0 0 0 5 1 0 1 5 2 0 2 5 3 0 3 5 4
97. z 2 kHz 10 kHz 3 Check that the measured frequency is accurate to the limits shown in Table B 2 for the applied test signal frequency and level and that the phase difference between channels meets the phase difference specification VM700T Option 40 41 42 Audio Measurements User Manual B 7 Ecce Gp Option 41 Triple Input Audio This section describes the differences in operation between Option 40 and Option 41 and it gives the verification procedure for Option 41 Configuring Source Selection Audio The Option 41 software is similar to the Option 40 software except for the Source Selection Audio file The Source Selection Audio file lets you specify an Option 41 audio input 1 2 3 for a video source A B C and then select an appropriate audio source file if you want to use an audio source file other than the system default In the next steps you want to have source A to audio input 1 source B to 2 and source C to 3 To specify audio inputs and audio source files for video sources use the following procedure 1 A on Rp From Measure Mode press the Configure front panel button touch the Configure Files soft key followed by the Source Selection Audio soft key Rotate the front panel knob to highlight the source A B C for which you are specifying an audio input and an audio source file Touch the highlighted audio input 1 2 or 3 to select it Rotate the front panel knob to change the audio input sel

User Manual VM700T Video Measurement Set Option 40/41/42

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