Polycom C16 - Manual (Page 348)

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12
A - 6
Virtual Channel Types
Virtual channels are operated on by the command set which can apply
parameter changes to the underlying physical channels. For example, setting
the fader parameter of a virtual channel would set the fader parameter for its
underlying physical channels.
There are two types of virtual channels in SoundStructure: mono virtual
channels and stereo virtual channels.
Mono Virtual Channels
Mono virtual channels are a representation of a single physical channel. All
parameters of the physical channel are controlled through the virtual channel.
An example of where a mono virtual channel would be used is a microphone
input.
Stereo Virtual Channels
Stereo virtual channels combine exactly two physical channels to create a
stereo pair. All controls and processing take into account the stereo nature of
the virtual channel. For example, when mono virtual channels are routed to
stereo virtual channels in the matrix, the SoundStructure device will send the
mono channel to both stereo channels with the appropriate gain. Additionally,
a pan control is available that allows adjustment of the relative signal level in
the left and right channels. An example of a stereo virtual channel would be a
stereo VCR signal.
Virtual Channel Groups
It is often convenient to refer to a group of virtual channels and control a group
of virtual channels with a single command. Virtual channel groups are used
with SoundStructure products to create a single object made up of loosely
associated virtual channels. Once a virtual channel group has been created, all
commands to a virtual channel group will affect the virtual channels that are
defined as part of the virtual channel group and command acknowledgements
from all the members of the virtual channel group will be returned. Virtual
channel groups may be thought of as a wrapper around a number of virtual
channels as shown in the following figure.
Vi
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Physical
Channel
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Physical
Channel
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Physical
Channel
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Physical
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Virtual Channel Group
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Physical
Channel
Left
Physical
Channel
Right