Data Translation DT3162, User Manual, Page: 19 / 80

Principles of Operation
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Sync Signals
This section describes the following aspects of the sync signals:
• Sync input sources, and
• Sync output mode.
Sync Input Sources
To digitize the incoming video signal, the DT3162 board requires both
a horizontal and a vertical sync input signal.
The way in which the board determines the sync information
depends on whether composite or variable-scan video signals are
connected to the board. Refer to the following subsections for more
information.
Composite Video Signal
If you use a composite video source, the sync signals are stripped
from the selected video source and fed into the sync circuitry. Specify
the sync input source as InternalSync using software.
Note: You set the horizontal sync input frequency by specifying the
line frequency, described on page 17 . The vertical sync input
frequency is the line frequency divided by the number of lines per
frame.
If you enable sync output mode, specify the sync input source as
internal, since the syncs coming back to the board are stripped from
the video source.