Technical data

DOC-01-TELAS-CRG-4 ASTi ACE Studio Components Reference Guide Rev.M
102 Copyright © 2014 Advanced Simulation Technology inc.
6.1. AGC
Summary: AGC attempts to keep audio at a consistent, specified volume.
Description: The Automatic Gain Control (AGC) component controls the volume
of the signal to keep the output close to a target volume. There are two stages in this
component, the AGC and the Limiter. In the AGC stage, signals above the target
are reduced, while signals below the target (and above the threshold) are
increased.The Limiter stage then acts to prevent any high peaks that may have been
induced by the AGC.
This component can be useful for a variety of volume leveling tasks, such as
evening out microphone volumes before the input of the speech recognition system.
Audio Input
InSignal
Type Default Value
audio n/a
Description: The signal that will be filtered. This input is linked
into the component from somewhere else in the model.
Control Inputs
Attack
Type Default Value
float32 250.0
Description: Determines how quickly the gain is turned up when
the level goes below the target. Values are in dB/sec. Higher attacks
produce a more aggressive rate of gain increase.
Enable
Type Default Value
boolean True
Description: Controls whether any gain adjustment will occur.
Control Inputs
LimEna-
ble
Type Default Value
boolean True
Description: Turns the limiter stage on or off in the component. If
True, the peak output levels of the AGC will not go above the
LimThreshold.
LimThres
hold
Type Default Value
float32 -18.0
Description: The maximum peak level in dB allowed in the output
signal. -18 corresponds to 0.125 linear.
OutGain
Type Default Value
float32 1.0
Description: A gain applied to the signal after the AGC stage.
Ratio
Type Default Value
float32 4.0
Description: Controls how much the signal level is pushed towards
the target. A ratio of 4.0 (4:1) means a signal of 4 dB from the target
will leave the AGC only 1 dB away. Higher ratios have more
“push”.
Release
Type Default Value
float32 250
Description: Determines how quickly the gain is turned down when
the signal level goes above the target. Values are in dB/sec. Higher
releases produce a more aggressive rate of gain reduction.