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2.2.
AUDIO IN AND OUT
The audio versions of the CDM (-A4 and –A8) have audio paths through the card that are
delayed/synchronized with the video. The –A4 version performs A to D conversion on 4 balanced analog
inputs (1 stereo pair per video channel), delays the audio to match the associated video, and outputs 1
AES channel that is synchronous to the associated video. One half group of delayed audio is embedded
on the output video. The –A8 version performs A to D conversion on 8 balanced analog inputs (4 channels
per video), delays the audio to match the associated video, and outputs 2 AES channels that are
synchronous to the associated video. One full group of delayed audio is embedded on each video output.
The –A4 version of the CDM uses a removable terminal strip to connect audio. To connect audio, pull out
the removable terminal strip and, with a small screw driver, connect bare wires following the connections
on the rear panel. If the audio is unbalanced (single-ended), connect the ground to both the ground input
and the –ve input while the signal is connected to the +ve input. Push the terminal strip back into the rear
panel making sure there is enough slack in the cabling to not put pressure on the connector.
The –A8 version of the CDM uses a slightly different removable barrier strip to connect audio. To connect
audio, pull out the removable barrier strip and insert bare audio wires following the connections on the rear
plate. Audio wires are secured in the barrier strip with a mechanical spring force. If the audio is
unbalanced (single-ended), connect the ground to both the ground input and the –ve input while the signal
is connected to the +ve input. Push the barrier strip back into the rear panel making sure there is enough
slack in the cabling to not put pressure on the connector
48kHz unbalanced 75 Ohm AES is available on the AES OUTPUT BNCs.
The AES outputs are always synchronous to the output video. This means that the AES is
frequency/phase locked to the video with an exact relationship between the number of audio samples and
the number of output video frames. If you also need the AES channel status bits aligned with an external
source, apply a Digital Audio Reference Signal (DARS) with the reference phase information. The card will
automatically align the channel status bits when any AES input signal is detected on the DARS input.
The DARS signal MUST be locked to the same genlock reference signal that the
CDM hardware is using. Otherwise, the channel status bits will slip in phase,
which may cause downstream AES equipment to detect a problem. When in
doubt, do not apply a DARS signal.
7736CD2 Dual Composite Decoder
Revision 1.0.4
7700 MultiFrame Manual
Page - 5
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