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 side, 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 'AGC Disable Fast Adaptation' parameter. After Fast Mode is used, the signal should be off for two minutes in order to have the feature turned on again.
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1.
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Open the DSP Settings page (Setup menu > Signaling & Media tab > Media folder > DSP Settings). |
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2.
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From the 'IPMedia Detectors' drop-down list [EnableDSPIPMDetectors], select Enable. |
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3.
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Configure the following AGC parameters: |
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'Enable AGC' [EnableAGC] - enables the AGC mechanism. |
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'AGC Slope' [AGCGainSlope] - defines the AGC convergence rate. |
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'AGC Redirection' [AGCRedirection] - defines the AGC direction. |
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'AGC Target Energy' - defines the signal energy value (dBm) that the AGC attempts to attain. |
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'AGC Minimum Gain' [AGCMinGain] - defines the minimum gain (in dB) by the AGC when activated. |
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'AGC Maximum Gain' [AGCMaxGain] - defines the maximum gain (in dB) by the AGC when activated. |
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'AGC Disable Fast Adaptation' [AGCDisableFastAdaptation] - enables the AGC Fast Adaptation mode. |
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4.
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Configure the 'Transcoding Mode' [TranscodingMode] parameter to Force. You can configure this using the global parameter or per IP Profile.
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