Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12
2 - 8
is processed by five different DSP algorithms: parametric equalization, acous-
tic echo cancellation, noise cancellation, feedback reduction, and echo
suppression (non linear processing).
Continuing through the signal path as shown in the next figure, the input
signal continues through the AGC (automatic gain control), dynamics process-
ing, an automixer, an audio fader, and finally through the input delay.
Each analog input signal is processed to generate three different versions of
the processed input signal that can be used simultaneously in the matrix:
1. Conferencing version,
2. Sound reinforcement version, and
3. Recording/ungated version
The AGC, dynamics processor, and input fader are linked together on all three
audio paths and apply the same gain to the signal paths based on an analysis
of the signal earlier in the signal path.
The automixer processing is only applied to the conferencing and sound rein-
forcement signal paths to ensure that there is an 'un'-automixed version of the
input signal available for recording/ungated applications.
Mic or Line
Input
Input to
Matrix
Input to
Matrix
Parametric
Equalization
A/D
Converter
Analog
Gain
Acoustic Echo
Cancellation
Noise
Cancellation
Automatic
Gain Control
Automixer
AGC Dynamics Fader Delay
Fader
Automixer
Automixer
Delay
Automatic
Gain Control
Non Linear
Processing
Feedback
Cancellation
Dynamics
Processor
Dynamics
Processor
Fader
Input to
Matrix
Automatic
Gain Control
Fader Delay
Dynamics
Processor
Delay
Mute
Router
Recording/
Ungated
Conferencing
Sound
Reinforcement
C-Series Input Processing
Mic or Line
Input
Parametric
Equalization
A/D
Converter
Analog
Gain
Acoustic Echo
Cancellation
Noise
Cancellation
Non Linear
Processing
Feedback
Cancellation
Route
C-Series Input Processing
Mic or Line
Input
Input to
Matrix
Input to
Matrix
Parametric
Equalization
A/D
Converter
Analog
Gain
Acoustic Echo
Cancellation
Noise
Cancellation
Automatic
Gain Control
Automixer
AGC Dynamics Fader Delay
Fader
Automixer
Automixer
Delay
Automatic
Gain Control
Non Linear
Processing
Feedback
Cancellation
Dynamics
Processor
Dynamics
Processor
Fader
Input to
Matrix
Automatic
Gain Control
Fader Delay
Dynamics
Processor
Delay
Mute
Recording/
Ungated
Conferencing
Sound
Reinforcement
Input to
Matrix
Input to
Matrix
Automatic
Gain Control
Automixer
AGC Dynamics Fader Delay
Fader
Automixer
Automixer
Delay
Automatic
Gain Control
Dynamics
Processor
Dynamics
Processor
Fader
Input to
Matrix
Automatic
Gain Control
Fader Delay
Dynamics
Processor
Delay
Mute
Recording/
Ungated
Conferencing
Sound
Reinforcement