Polycom SoundStructure C16 Design Manual page 25

The AGC, dynamics processor, and input fader are linked together on all three audio paths, and each apply
the same gain to the signal paths based on an analysis of the signal earlier in the signal path.
The automixer processing is applied to the conferencing and sound reinforcement signal paths to ensure
that there is an un-automixed version of the input signal available for recording/ungated applications.
Note: Analog Input Signal Processing
Each analog input signal is processed to create three processed versions that can
be used in different ways in the matrix.
These three different versions of the input signal mean that, at the same time, an output signal to the
loudspeakers can use the sound reinforcement processed version of an input signal, an output signal to the
video conferencing system can use the conferencing processed version of the input signal, and an output
signal to the recording system can use the recording processed version of the input signal. The decision of
which of these three processed versions is used is made at each matrix crosspoint on the matrix as
described in the Creating C-Series Matrix Crosspoints
Processing Conferencing Version
The conferencing version is processed with the acoustic echo and noise cancellation settings, non-linear
signal processing, automatic gain control, dynamics processing, automixer, fader, delay, and input mute.
The conferencing signal path and summary block diagram is highlighted in the following figure. This is the
path that is typically used to send echo and noise canceled microphone audio to remote locations. This is
the default processing for microphone inputs when the automixed version of the signal is selected.
SoundStructure C-Series Conferencing Processing Signal Path
C-Series Conferencing Input Processing
Mic or Line Analog A/D Parametric
Input Gain Converter Equalization
Parametric
Equalization
Processing Sound Reinforcement Version
The sound reinforcement version is processed with the echo and noise cancellation, optional feedback
elimination processing, automatic gain control, dynamics processing, automixer, fader, delay, and input
mute. This is the path that is typically used for sending local audio to loudspeakers in the room for sound
reinforcement. There is no non-linear processing on this path so that the local talker audio to the
loudspeakers is not affected by the presence of remote talker audio in the local room.
Polycom, Inc.
Non Linear
Acoustic Echo Noise
Processing
Cancellation Cancellation
Feedback
Reduction
Non Linear
Acoustic Echo Noise
Cancellation Cancellation Processing
section below.
AGC Dynamics
Automatic Dynamics
Gain Control Processor
Automixer
Automatic Dynamics
Automixer
Gain Control Processor
Automatic Dynamics
Automixer
Gain Control Processor
Dynamics
Automatic
Automixer
Gain Control Processor
Fader Delay Mute
Input to
Fader Delay
Matrix
Input to
Fader Delay
Matrix
Input to
Fader Delay
Matrix
Fader Delay Mute
Recording/
Ungated
Conferencing
Sound
Reinforcement
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