AGC

Automatically adjusts gain to maintain output waveform amplitude

  • Library:
  • SerDes Toolbox / Datapath Blocks

Description

The AGC block applies an adaptive variable gain to the input waveform to achieve a desired RMS output voltage. Averaging the RMS voltage over a specified number of symbols, AGC performs automatic gain control (AGC) by increasing or decreasing the gain, or keeping the gain constant.

Ports

Input

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Input baseband signal. The input signal can be a sample-by-sample signal specified as a scalar, or an impulse response vector signal.

Data Types: double

Output

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Gain adjusted output signal. If the input signal is a sample-by-sample signal specified as a scalar, the output is also scalar. If the input signal is an impulse response vector signal, the output is also a vector.

Data Types: double

Parameters

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AGC operating mode:

  • OffAGC is bypassed, the input waveform remains unchanged.

  • OnAGC adjusts gain of input waveform to maintain Target RMS voltage in output waveform.

Programmatic Use

  • Use get_param(gcb,'Mode') to view the current AGC Mode.

  • Use set_param(gcb,'Mode',value) to set AGC to a specific Mode.

Desired RMS voltage of the output waveform, specified as a real scalar in the range [0.003, 10] in volts.

Programmatic Use

  • Use get_param(gcb,'TargetRMSVoltage') to view the current value of Target RMS voltage (V).

  • Use set_param(gcb,'TargetRMSVoltage',value) to set Target RMS voltage (V) to a specific value.

Data Types: double

Maximum allowed AGC gain, specified as a positive real scalar. Maximum gain provides a stable startup of the adaptive algorithm.

Programmatic Use

  • Use get_param(gcb,'MaxGain') to view the current value of Maximum gain.

  • Use set_param(gcb,'MaxGain',value) to set Maximum gain to a specific value.

Data Types: double

Averaging length, specified as a positive real integer. Averaging length defines the number of symbol over which the RMS calculation of the input signal is made.

Programmatic Use

  • Use get_param(gcb,'AveragingLength') to view the current value of Averaging length.

  • Use set_param(gcb,'AveragingLength',value) to set Averaging length to a specific value.

Data Types: double

IBIS-AMI parameters

Select to include Mode as a parameter in the IBIS-AMI file. If you deselect Mode, it is removed from the AMI files, effectively hard-coding Mode to its current value.

Select to include Target RMS voltage as a parameter in the IBIS-AMI file. If you deselect Target RMS voltage, it is removed from the AMI files, effectively hard-coding Target RMS voltage to its current value.

Introduced in R2019a