Data Translation DT3153, Руководство пользователя

Страница: 27 / 140

Principles of Operation
11
2
2
2
2
2
2
2
2
2
Sync Signals
This section describes the following aspects of sync signals:
• Sync signal selection, and
• Sync Master mode.
Sync Signal Selection
To digitize the incoming video signal, the DT3153 frame grabber
requires both horizontal and vertical sync signals. The DT3153 board
determines this sync information from the video input signal being
digitized.
Sync Master Mode
On the DT3153, you can enable or disable Sync Master mode. In Sync
Master mode, the DT3153 board generates the following sync signals:
• A horizontal sync signal (HSYNC_OUT), output on pin 9 of
connector J1.
• A vertical sync signal (VSYNC_OUT), output on pin 10 of
connector J1.
• A composite sync signal (CSYNC_OUT), output on pin 11 of
connector J1.
These signals comply with the NTSC (60 Hz) or PAL (50 Hz) format
and can be used to drive one or more cameras, if desired.
The video signal from the camera is digitized as usual, using the
syncs generated by the board as the sync basis. This process is called
gen-locking . Gen-locking allows you to synchronize signals when
switching among channels.
By default, Sync Master mode is enabled on the DT3153.