Ross LDP-8242, User Manual, Page: 17 / 100

LDP-8242 User Manual (Iss. 03) Introduction • 1–9
Audio Subsection Overview
Descriptions below include some functions and features that are available only as options.
Audio Processing Overview
The LDP-8242 audio processing subsection is built around a card internal 16-channel bus. This
16-channel bus receives inputs from an input routing crosspoint that routes de-embedded and
discrete AES signals over the 16-channel bus. Correspondingly, at the output end of the
16-channel bus is an output routing crosspoint that in turn distributes the 16-channel bus signals
to embedded and discrete AES audio outputs. An Audio DSP function (which interfaces with the
output routing block) provides eight tone generators and advanced functions such as loudness
processing and upmixing. The routing and Audio DSP functions are described in detail later in
this section.
As such, the audio subsection provides a full crosspoint between all supported audio inputs and
output formats.
The audio subsection allows choices from the following audio inputs:
• 16 channels of de-embedded audio from the SDI program video path
• Up to 16 channels (8 pairs) of discrete AES input
• Up to 10 channels of decoded Dolby® E or AC-3 audio
• Digital silence (mute) setting
The audio subsection allows routing to the following audio outputs:
• 16 channels of embedded audio on the SDI output
• Up to 16 channels of discrete AES output on eight AES pairs
All embedded and AES channels have status displays that show the following for each channel
pair:
• PCM signal presence
• Dolby® E® signal presence
• Dolby® Digital® signal presence
• Missing (no signal detected)
Embedded, and AES input channel pairs also have displays showing slow-ballistics true peak
levels for each pair. Embedded and AES channels at digital silence signal level show Mute.
Output audio rates are always 48 kHz locked to output video, but discrete AES inputs can pass
through the sample rate converters to align these inputs with the output timing. Output AES is
always precisely synchronized with the output video.
Note
— Practical AES channel count handled by the card is 8 pairs, of which each
pair can be user GUI-selectable as an input or output.