Nevion ARC-SD-DMUX - Manual (Page 18)

ARC-SD-DMUX Rev. B
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3.13.3 Audio cross point matrix
The audio cross point matrix is a 10x10 cross point with inputs and outputs as shown in
Figure 3. The 8 de-embedded channels, a 1 kHz sine a
nd “mute” are selectable inputs.
“mute” is explained in chapter 3.1. The outputs of the cross points are 8 stereo channels for
re-embedding, one analog audio output and one AES output.
3.13.4 Audio fallback options
The 10 output channels from the cross point matrix have configurable fallbacks, used when
their corresponding sources are missing. The eight embedder channels have one fallback
setting and the audio DAC channel and AES out have their own settings.
The priorities can be selected between matrix (being the selected channel in the cross point
matrix) or the internally generated sine, mute or delete/output off.
3.13.5 Audio generator
The stereo audio generator is available as an input to the audio cross point matrix and as a
fallback option. There are three slightly different ways to select the generator:-

select it in the matrix directly

select it as the first priority in the audio fallback setting

select it as second priority behind a missing input
The generator signal is a high purity 1 kHz sine wave with a 250ms interruption on the left
channel every 3 seconds. The audio level may be set to one of two standards, -18 dBFS
and -20 dBFS. These two levels correspond to EBU R68 and SMPTE RP155.
3.13.6 Audio processing block
The output of each stereo signal from the audio cross point matrix has an audio processing
block. This is controlled with the Multicon GYDA controller. The processing includes
channel L/R manipulation and audio gain.
3.13.6.1 Channel L/R manipulation
The stereo signals may be output in one of the following ways:
- LR, Left / Right No change.
- RL, Right/ Left Channels are swapped.
- LL, Left/ Left Left channel is copied into the right channel.
- RR, Right/ Right Right channel is copied into the left channel.
- !LR, ØLeft/ Right The left channel is phase inverted.
- L!R, Left/ ØRight The right channel is phase inverted.
- MM, (Left + Right)/2 The left and right channels are summed.
- MS, MS/AB The left and right channels are converted from AB stereo
to MS stereo.
The sum products (L+R/2 and MS) are reduced in level by 6 dB to avoid any possibility of
clipping.
3.13.6.2 Audio gain
The gain may be set to +-96dB with a gain step of 0.1dB.
Note that non-audio data is ignored and left unchanged by the gain function.