TM 11-6625-3081-23
7-31.
VIDEO SIGNAL GENERATOR (VSG) CASE ASSEMBLY 2A2A7A1
7-31
INPUT CODE:
VSGST (cont)
a. DESCRIPTION (cont)
The VSG is then programmed for an 875 line rate and the blanking level for 0.3
volts.
The displayed video output is measured by the programmable digitizer, which
is triggered by the VSG and the following checks made:
The horizontal sync width for 2.0 to 3.5 microseconds.
The horizontal sync period for 35.0 to 40.0 microseconds.
The porch level of the display output signal for -0.075 to +0.75 vdc.
The difference between the porch level and the sync level for +0.1 to
+0.4 vdc.
The time from the start of the last horizontal sync of the even field to the
beginning of the odd vertical sync for 36.0 to 40.0 microseconds.
The time from the start of the odd field vertical sync to the start of the
first pulse for 15.0 to 19.0 microseconds.
The time from the start of the odd field vertical sync to the start of the
sixth pulse for 112.0 to 116.0 microseconds.
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.O. 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 to 19.6 to 20.4 microseconds.
The amplitude of the window for +0.25 to +0.75 vdc.
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