Automatic Gain Control (Agc) - AudioCodes Mediant 2000 User Manual

User's Manual
If the device detects voice and not an answering machine, the SIP INFO message
includes:
Type= AMD
SubType= VOICE
If the device detects silence, the SIP INFO message includes the SubType SILENT.
Note:
Machine Detection' on page 478.

13.4.2 Automatic Gain Control (AGC)

Automatic Gain Control (AGC) adjusts the energy of the output signal to a required level
(volume). This feature compensates for near-far gain differences. AGC estimates the
energy of the incoming signal from the IP or PSTN, determined by the 'AGC Redirection'
parameter, calculates the essential gain, and then performs amplification. Feedback
ensures that the output signal is not clipped. You can configure the required Gain Slope in
decibels per second using the 'AGC Slope' parameter and the required signal energy
threshold using the 'AGC Target Energy' parameter.
When the AGC first detects an incoming signal, it begins operating in Fast Mode, which
allows the AGC to adapt quickly when a conversation starts. This means that the Gain
Slope is 8 dB/sec for the first 1.5 seconds. After this period, the Gain Slope is changed to
the user-defined value. You can disable or enable the AGC's Fast Mode feature, using the
ini file parameter AGCDisableFastAdaptation. After Fast Mode is used, the signal should
be off for two minutes in order to have the feature turned on again.
Note:
License Key installed on the device.
The procedure below describes how to configure AGC using the Web interface:

To configure AGC using the Web interface:
1. Open the IPMedia Settings page (Configuration tab > VoIP menu > Media submenu
> IPMedia Settings). The AGC parameters are shown in the figure below:
Figure 13-12: AGC Parameters in IPMedia Settings Page
2. Configure the following parameters:
•
'Enable AGC' (EnableAGC) - Enables the AGC mechanism.
•
'AGC Slope' (AGCGainSlope) - Determines the AGC convergence rate.
•
'AGC Redirection' (AGCRedirection) - Determines the AGC direction.
•
'AGC Target Energy' - Defines the signal energy value (dBm) that the AGC
attempts to attain.
3. Click Submit to apply your settings.
Version 6.6
For information on Syslog fields for AMD, see 'Syslog Fields for Automatic
AGC is a customer ordered feature and thus, must be included in the Software
175
13. Media
Mediant 2000