Sam Sirius 840 User Manual page 337

Sirius 800 Series User Manual
C.4.3.2 16 Channel Mixer
There are 16 Mixers available per video output channel and each mixer can mix up to 16
channels of audio. Each 16 channel mixer is used to mix two or more audio output channels
together to create a single mono signal that is output from the mixer.
For example, using Mixer 6 to mix the stereo pair of channels 1 and 2 would result in a single
mono signal being output from Mixer 6.
The mixing process is purely additive and the gain of the mixed signal will need to be reduced
to ensure it has the correct gain level.
C.4.3.3 Channel Swap (Shuffle)
The channel shuffler is used to change the channel order of one or more of the audio
channels
For example, this might be used if a stereo pair arrives at the router as right, left and they
need to be swapped to left, right to match the house reference.
C.4.3.4 Gain control
Gain is applied to an audio output channel as Silence (mute) or in steps of 0.1dB in a range of
-72 dB to +30 dB.
For example, this might be used when the feed is destined for another country that requires a
specific audio level that is different from the current audio level.
C.4.3.5 Phase Invert
Phase invert will invert the audio waveform.
For example, this might be used if one channel of a stereo pair is out of phase with the other.
C.4.3.6 5925 Connections to the Audio Crosspoints
The 5925 video output module receives two identical multiplexed audio transport streams,
each of which contains all of the audio channels on the output module (up to 768 mono
channels). One transport stream is received from the main audio crosspoint module and a
duplicate transport stream is received from the redundant audio crosspoint module. The
output module monitors the transport streams received from each of the audio crosspoint
modules for errors. If an error is found the output module will use the transport stream from
the other audio crosspoint module if it is fitted.
Important:
Iss 5 Rev 7
• Due to the nature of multiplexed audio transport streams there is an extremely
small delay between groups of channels as the transport stream is constructed. If
the audio is locked to the input these delays will need to be considered.
• If the audio is locked to an external reference these delays are managed by the
router and the audio will remain co-timed.
Output Modules Modules No Longer Supplied With New Systems C.4
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