TM 11-6625-3025-14/ET426-AA-MMA-010/E154 VII210/T.O. 33A1-8-902-1-1
(2) Synchronizing pulses conform to EIA Standard RS-343A.
(3) Resolution pattern content be presented in 100 tv line increments. That is, if ten bursts are presented
they will be in the order of 100, 200, 300, 400, 500, 600, 700, 800,900 and 1000 tv lines for the scan rate
in use.
(4) The window pattern provide a 25% duty cycle. Therefore, the white window pattern would appear as a
white rectangle in the center of a black background, the white center covering 25% of the total display
area (25% white, 75% black).
(5) The bar/dot patterns be based on 14 vertical and 17 horizontal elements (i.e., 14 H bars and 17 V bars).
(6) The gray scale characteristic should be linear, composed of black, white and eight intermediate shades
of gray.
Amplitude and impedance have been outlined in EIA Standards. A 75-ohm system is supplied unless specified
otherwise as a modification. Video signal amplitudes may be at one of two common levels:
(7) Video maximum level of 1.0v (including a blanking pedestal of 0.055v) plus sync of 0.4v, making an
overall composite video signal of 1.4v pk-pk.
(8) An overall composite video signal of 1.0v, composed of a video maximum level of 0.714v (including a
blanking pedestal of 0.4v) plus a sync level of 0.286v.
This instrument normally is adjusted to condition step (7), with a total 1.4v pk-pk composite video signal output.
Internal adjustments permit maximum levels as outlined in condition step (8), if desired.
There is no definitive standard on dc condition for video or synchronizing signals in television systems. The video
output signal is direct coupled to avoid the slightest tilt in the video frame for some patterns. The blanking level (blacker-
than-black) is at approximate ground (zero voltage) with the video portion positive going and sync portion negative going.
Tolerances have not been standardized in the television industry and often vary according to particular system
requirements. Therefore, adjustments called out herein are described without specific tolerance range. Pulse width
settings are observed upon an oscilloscope display, in which close setting is a matter of technician care in procedure. In
factory calibration, a tolerance of +5% is assumed as a maximum allowance on all oscilloscope measurements i.e., a
pulse width of 10 usec must be within +0.5 usec to be considered acceptable. Pattern content, such as the number of bar
elements length of gray scale, etc., is somewhat arbitrary, to be set according to user's judgment as desired in the display
of the signal. The scan rate is
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