TM 11-6625-3025-14/ET426-AA-MMA-010/E154 VII210/T.O. 33A1-8-902-1-1
presentation in the vertical dimension of the television raster). Interconnections are provided on the sync count card to
determine the number of horizontal lines in the frame.
Vertical pulses, initiated by the V trigger, are controlled for proper width by count of horizontal lines. A matrix is
included on the sync count card to control width of the V blanking and V drive pulses. The V sync pulse is at all times
delayed by a 3H front porch from the start of V blanking and always is 3H (the time of three horizontal lines) in width.
4-3.
Pattern Generator. (See figure FO-2). Synchronizing information is received at the pulse input card where the
pulses are processed to correct polarity, dc level, and pulse width for generation of the signals as desired. A basic
horizontal gate is developed from H drive to control horizontal pattern elements, and a vertical gate is developed from V
drive for development of vertical elements. The blanking signal is processed for development of the pedestal (setup) in
the composite and non-composite video signal; the level is adjustable on the video card. Blanking also is used for
synchronizing of the resolution signals to provide the most stable signal possible. The sync signal is processed only for
addition to the output video signal, if a composite video signal is desired at the output. The level of this pulse may be
reduced to zero by a control on the video card to develop a non-composite video signal.
The circuits develop the various individual patterns and are contained on separate removable plug-in circuit cards.
The basic amplitude control and the gray scale signal, which is analog in nature, is developed by the gray scale control,
gray scale and other associated control cards. The complete analog signal is routed to the level control on the control
panel to determine the amplitude of the video portion of the output signal. This signal is submitted to the video card where
it is mixed with other digitally formed pattern elements to develop the complete video portion of the output signal. If the
gray scale waveform is not being used, the gray scale control card produces only a dc level that is used to clip off digital
pattern elements, acting as an amplitude (video level) control.
The digitally derived patterns with selectable polarity (bar, dot, H bar, V bar, window, V stripe and H stripe) are
routed to the polarity card where either white or black pattern elements are developed as desired, when routed to the video
card.
The resolution signals are emitter coupled from the separate resolution cards directly to the video card to preserve
the very fast rise and fall times of these signals.
4-7
