Cobalt Digital COMPASS 9301 AES Audio Delay - Manual (Page 11)

9301-OM (V4.2) 9301 PRODUCT MANUAL 1-7
Introduction
9301 Functional Description
Audio Delay and Timing Function
Delay controls for each AES output channel provide independently adjustable
Input/Output delay ranging from 0.20 msec to 21 seconds (21000.00 msec).
Audio data blocks are sequentially held in independent buffers and released
per the delay setting at the intervals dictated by the delay setting and the
user-selected timing reference source.
The 9301 allows selection from the following reference timing sources:
• AES Input – Timing is derived from the lowest-numbered AES input
BNC that is used. (For example, if
AES IN 3 , AES IN 5 , and AES IN 8
are used, AES IN 3 serves as the timing master with AES IN 5 and
AES IN 8 being accordingly re-sampled).
Using AES input reference timing, all outputs can for example be
slaved to a DARS reference by simply connecting the DARS
reference to the lowest-numbered AES input being used. In this
manner, all other inputs will be re-sampled to sync with the DARS
channel.
• Reference 1 and Reference 2 Frame References – Timing is
derived from an external frame sync reference signals distributed
with the card frame (
Ext. Frame Ref IN in Figure 1-1), thereby
allowing the audio to be synchronized to a black burst or tri-level
video reference.
• Local – Timing is derived from the card’s internal clock with no
association to external signal timing.
Audio Routing Description
The audio processor operates as an internal audio router. The router function
chooses from the following inputs:
• 16 channels (8 pairs) of discrete AES input
• Four independent internal tone generators (described below)
• Digital silence (mute) setting
The router function in turn provides 16 channels of discrete AES output on
eight AES pairs.
The router acts as a full audio cross point. Each of the 16 AES output
channels can receive signal from any one of the 20 input sources (16 discrete
AES input channels, or any of four internal tone generators). Unused output
channels can be mapped to a “Silence” source. Each output also provides gain
adjustment and selectable polarity inversion.