Nevion AVA-MUX - Manual (Page 16)

AVA-MUX Rev. C
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“Shuffling” of groups is when existing embedded audio groups are re-assigned to different
groups. Copying of groups is also possible i.e. Group 1 may be transported to Group 1 and
duplicated to Group 2. This function also takes place in the group router which means that
there is no extra delay.
3.2.2.5 Audio generator
The stereo audio generator is available in the audio router as a source. It 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 RP 155.
3.2.2.6 Video generator
The video generator has several different simple signals:

Color bar, 100% white, 75% colors, no set-up level.

Red, Green, Blue or Black full field.
The generator may be used as a backup video source if there is no video signal present at
either of the video inputs. The generator may also be switched on with GYDA. This will
override video input but the generator signal will be locked to the input.
The video standard of the generator may be set with GYDA but only if there is no video input
present.
3.2.3 Data transmission
The module can de-embed and embed asynchronous data. An AES3 audio signal is used as
a carrier. Both embedded audio and normal AES3 signals may be used to carry the RS422
data. The fiber connection usually only goes one direction so any desired return path must
be created by the user with another circuit. Return data may be sent over fiber via a link
comprising of AV-HD-XMUX, AAV-HD-XMUX, AAV-HD-DMUX, AES, D422 or D422-MG
modules.
The data input on the back panel works in one of two modes:
1. UART Mode: The data is checked for correct reception according to the configuration.
The data words are packaged and sent when present.
2. Raw sampling mode: The data input is sampled at 93.75 kHz and embedded as a
data stream. No checking is performed.
3.2.3.1 Data latencies
The data channel has a total latency of approximately 30µs when using raw sampling.
Normal data rates of up to 9600 may be used with raw data sampling to have a low latency.
The latency is 500µs when using the normal data encoding due to the block structure of the
AES User bits.
The configuration of the data channel is always stored in the module and used regardless of
the GYDA override switch.
3.2.3.2 Embedding
The AAV-SD-XMUX has a RS422 data input for the embedding of control data. The baud
rate and other parameters are configured with GYDA. The factory default is 115200 baud, no
parity, one stop bit.
The data channel is encoded in the User bits in an embedded audio stereo signal assigned
with GYDA. The factory default is Audio channels 1&2 in Group 1.
The data is sampled asynchronously at a constant bit rate. The range of baud rates that may
be transmitted is from DC to 115,200 bps. The data bytes are either encoded as packets in
the transmitted data or transmitted as an asynchronous bit stream which may also be used to
transmit a DC signal such as GPI.