Polycom SoundStructure C16 Design Manual page 26

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12
Non Linear
Mic or Line Analog A/D Parametric Acoustic Echo Noise
Input Converter Equalization Cancellation Cancellation Processing
Gain
Feedback
Cancellation
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).
C-Series Input Processing
Mic or Line Analog A/D Parametric Acoustic Echo
Input Gain Converter Equalization Cancellation
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.
AGC Dynamics Fader Delay Mute
Automatic Dynamics Input to
Recording/
Fader Delay
Gain Control Processor Matrix
Ungated
Automixer
Automatic Dynamics Input to
Automixer Fader Delay Conferencing
Gain Control Processor Matrix
Sound
Automatic Dynamics Input to
Automixer Fader Delay
Gain Control Processor Matrix Reinforcement
AGC
Automatic
Gain Control
Automatic
Gain Control
Automatic
Gain Control
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.
AGC Dynamics
Automatic Dynamics
Gain Control Processor
Router
Automixer
Non Linear
Noise Automatic Dynamics
Automixer
Processing
Cancellation Gain Control Processor
Feedback Automatic Dynamics
Automixer
Cancellation Gain Control Processor
Mic or Line A/D
Analog
Converter
Input Gain
Dynamics Fader
Dynamics
Fader
Processor
Automixer
Dynamics
Automixer Fader
Processor
Dynamics
Automixer Fader
Processor
Fader Delay Mute
Recording/
Input to
Fader Delay
Matrix Ungated
Input to
Fader Delay Conferencing
Matrix
Sound
Input to
Fader Delay
Matrix Reinforcement
C-Series Input Processing
Parametric Acoustic Echo Noise
Equalization Cancellation Cancellation
Delay Mute
Input to
Delay
Matrix
Input to
Delay
Matrix
Input to
Delay
Matrix
Route
Non Linear
Processing
Feedback
Cancellation
Recording/
Ungated
Conferencing
Sound
Reinforcement