Data Translation DT3120, Руководство пользователя

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Principles of Operation
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Sync Signals
To digitize the incoming video signal, the DT3120 board requires both
horizontal and vertical sync signals. The board determines this
information, as well as the odd and even fields, from the video input
signal being digitized.
Horizontal sync pulses are asserted low for 4
µ
s typically. Vertical
sync pulses are asserted low for 230
µ
s typically. The odd field
indication changes state on the falling edge of the vertical sync signal.