Nevion AVA-MUX - Manual (Page 5)

AVA-MUX Rev. C
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1.4 Signal flow
Figure 1: AVA-MUX signal flow
The analog video input signal type is identified. The synchronization information in the analog
signal is detected. The analog signal is digitized to a 10-bit parallel signal. An FPGA adds
EDH information and Field 1 marking. The signal is serialized and goes to the embedder
card. The video is de-serialized and passed to the embedding processor which inserts the
digital audio. The video signal is then re-serialized and sent to the electrical and optical
outputs.
The audio embedder module has two main processing blocks. One processes the video
stream and the packet data, the other processes the audio. The packet processing core
forms a group router which can route embedded audio between groups without any extra
delay.
The AAV-SD-XMUX audio core is an AES3 stereo audio router. The received embedded
audio and the audio inputs are the sources in the router. The embedded output groups and
AES3 outputs are the destinations. This feature may also be used to perform stereo channel
swapping.
Four stereo delay lines are also available in the router with a total combined delay of 1.25s.
Audio processing is possible within each stereo output. The channels may be changed
allowing L/R swapping, mono assignment, summing, MS conversion and phase reversal of
one of the signals.
There are two embedding modes:

Non-SRC mode: The AES3 input signals are embedded transparently.

Automatic mode: The module will use sample rate converters when necessary.
Data signals such as Dolby E will always be embedded transparently without using the
sample rate converters.
All embedding and de-embedding is performed with synchronous 48 kHz audio.