Grass Valley DAP-1781 - Manual (Page 5)

DAP-1781 | 5
1 DAP-1781 8 Channel Digital Audio Processor
1.1 Introduction
The DAP-1781 is an eight-channel high quality digital audio processor designed to work alone or with a
wide range of video converters, frame synchronizer proc/amps of the Densité series.
The card features two distinct processing blocks: Input and Output. The input processing includes Dolby
detection, Tone generator, delay adjustments, level controls and phase correction. Delay components
include a fixed delay of up to 2 seconds as well as a video tracking delay that will automatically track the
varying saw tooth delay introduced by an associated video frame synchronizer.
The output processing block includes full channel shuffling, an additional gain/attenuation stage and
mixing. Each odd output channel is a mix of any two input channels, and a 4-channel mixing is available
on the even output channels.
Additional audio functions such as a 16 channel dynamic processing (compressor/limiter and expander)
and/or Downmixing (5.1 to LtRt) and Upmixing (2.0 to 5.1) are available as options.
The DAP-1781 offers the possibility to integrate a Dolby-E encoder, a Dolby-E and AC-3 decoder, a Dolby
Digital AC-3 encoder or an upMAX
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Upmixer module. One module at a time can be installed on the card.
The use of a 16 channel card-to-card audio bus allows the DAP-1781 to work with one video card and one
other audio processor card. When connected to a video card, the DAP-1781 can process 8 channels of
audio originating from the video card; once processed, the signals are sent back to be embedded, and are
also available at the digital outputs.
Along with the audio channels, the Audio bus carries the timing, delay signaling and Dolby Metadata.
When combining cards together all audio processing is synchronous and in phase, ensuring proper
alignment and matched delay.
User-defined channel identification data may be encoded in the AES status bits. An input audio signal
status is also available indicating input signal presence or overload.
The card is housed in a (DENSITÉ) frame, with a single or double width rear connector panel. Based on
the rear module installed, the DAP-1781 is compatible with the AES3 or AES-3id digital audio standard.