TM 11-6625-3025-14/ET426-AA-MMA-010/E154 VII210/T.O. 33A1-8-902-1-1
Figure 6-11. Oscilloscope Display of the V BAR Signal Waveform, White Polarity
NOTE
Adjustment of the V bar is complicated by the fact that current standards do not
provide a constant percentage of inactive blanking time for the various scan rates.
Therefore, adjustment must be based upon the active time of the television
scanning line only. Based upon the 525-line, 4:3 aspect ratio precedent, calibration
for this rate provides element spacing of 1/20 total line time, or 3.17 usec, between
elements. Referred to the nominal active time, elements occur at intervals of
0.0605t (t = active line time). Therefore, the calibration of width between adjacent V
bars shall be based upon 0.0605 times the active line duration for all scan rates,
providing 17 visible bars in the length of as canning line for the 4 x 3 aspect ratio of
0.071t for the 1 x 1 aspect ratio.
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