Nevion DAC-AVA-DMUX - Manual (Page 28)

DAC-AVA-DMUX Rev. A
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4.3.17 Audio cross point matrix
The audio cross point matrix is a 10x10 cross point with inputs and outputs as shown in
Error! Reference source not found.. The 8 de-embedded channels, a 1 kHz sine and
“black sound” are selectable inputs. “Black sound” is explained in chapter Error! Reference
source not found.. The outputs of the cross points are 8 stereo channels for re-
embedding, one analog audio output and one AES output.
4.3.18 Audio fallback options
The 10 output channels from the cross point matrix have configurable fallbacks, used when
their corresponding matrix inputs are missing. A common fallback setting is used for all
eight re-embedded channels, whereas the audio DAC channel and AES out have their own
independent fallback settings. The priorities can be selected between matrix (being the
selected channel in the cross point matrix) or the internally generated sine or black sound.
4.3.19 Audio generator
The stereo audio generator is available as an input to the audio cross point matrix, and as a
fallback option. There are therefore three slightly different ways to select the generator:
select it in the matrix directly, select it as the first priority under audio fallback, or to set 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. The two
levels are -18 dBFS and -20 dBFS. These two levels correspond to EBU R68 and SMPTE
RP155.
4.3.20 Audio processing block
The output of each stereo signal from the audio cross point matrix may be manipulated in
the audio processing block (LL, RR, LR, RL !LR, L!R, (L+R)/2, MS).
The stereo signals may be output in one of the following ways:
- LR, Left / Right Normal, 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.
4.3.21 Audio embedder
The audio embedder can be enabled/disabled per group. When a group to be embedded is
disabled the audio inside that group is removed.
A 24-bit audio signal uses the Extended Audio Data Packet for the 4 least significant bits.
Not all equipment can handle Extended Audio Data Packets correctly, so the option exists
to truncate all audio data to 20 bits. This setting is common for all embedded channels.
The insertion of Audio Control Packages can also be switched on and off. This setting is
also common for all embedded channels.
For SD input (i.e. operation as a frame synchronizer) the audio embedder can also be
switched off all together. In this state all audio embedded on the input signal is left
unchanged.