TM 11-6625-3081-23
2-14. MODULE DESCRIPTIONS (cont)
2-14
c.
TEST CONSOLE TEST BENCH 2A2 (cont)
Input Code
VSGST (cont)
Description
The time from the start of the sixth pulse of the odd
field vertical sync to the next positive transition for
3.0 to 6.0 microseconds.
The time from the first positive transition after the odd
field vertical sync to the start of the next horizontal
sync for 34.0 to 36.0 microseconds.
The time from the start of the last horizontal sync of the
odd field to the beginning of the even field vertical sync
for 15.0 to 22.0 microseconds.
To check composite video without sine wave, a 20-microsecond
window is placed 11 microseconds after the start of horizontal
sync.
The brightness level is programmed to +1.0 vdc and the
programmable digitizer assembly is triggered 10 microseconds after
the start of horizontal sync and the following checks made:
The window to start 0.6 to 1.4 microseconds after the
trigger.
The width of the window for 19.6 to 20.4 microseconds.
The amplitude of the window for +0.25 to +0.75 vdc.
To check the composite video with sine wave, the window in the
previous check is reprogrammed to a brightness level of +0.5 vdc
and modulated with a 10 mHz sine wave programmed for 0.5v p-p.
The difference between the maximum and minimum samples during the
window is checked for 0.25 to 0.30v p-p. The camera sync signals
are checked with the VSG programmed for an 875 line rate.
The
programmable digitizer assembly is triggered 10 microseconds into
line 18, and samples the camera sync (encoded sync) signals. The
following checks are made:
The second pulse of the inverted sync signal for 3.7 to
3.9 microseconds.
The third pulse of the inverted sync signal for 3.7 to
3.9 microseconds.
The time interval between the first and second pulses of
the inverted sync signal for 37.6 to 38.6 microseconds.
The time interval between the end of the second pulse and
the start of the third pulse of the inverted sync signal
for 0.9 to 1.1 microseconds.
2-81
