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/* -*- c++ -*- */
/*
* Copyright 2002,2006 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef _GRI_AGC2_FF_H_
#define _GRI_AGC2_FF_H_
#include <gr_core_api.h>
#include <math.h>
/*!
* \brief high performance Automatic Gain Control class with attack and decay rate
*
* Power is approximated by absolute value
*/
class GR_CORE_API gri_agc2_ff {
public:
gri_agc2_ff (float attack_rate = 1e-1, float decay_rate = 1e-2, float reference = 1.0,
float gain = 1.0, float max_gain = 0.0)
: _attack_rate(attack_rate), _decay_rate(decay_rate), _reference(reference),
_gain(gain), _max_gain(max_gain) {};
float attack_rate () const { return _attack_rate; }
float decay_rate () const { return _decay_rate; }
float reference () const { return _reference; }
float gain () const { return _gain; }
float max_gain () const { return _max_gain; }
void set_attack_rate (float rate) { _attack_rate = rate; }
void set_decay_rate (float rate) { _decay_rate = rate; }
void set_reference (float reference) { _reference = reference; }
void set_gain (float gain) { _gain = gain; }
void set_max_gain (float max_gain) { _max_gain = max_gain; }
float scale (float input){
float output = input * _gain;
float tmp = (fabsf(output)) - _reference;
float rate = _decay_rate;
if(fabsf(tmp) > _gain)
rate = _attack_rate;
_gain -= tmp*rate;
#if 0
fprintf(stdout, "rate = %f\ttmp = %f\t gain = %f\n", rate, tmp, _gain);
#endif
// Not sure about this
if (_gain < 0.0)
_gain = 10e-5;
if (_max_gain > 0.0 && _gain > _max_gain)
_gain = _max_gain;
return output;
}
void scaleN (float output[], const float input[], unsigned n){
for (unsigned i = 0; i < n; i++)
output[i] = scale (input[i]);
}
protected:
float _attack_rate; // attack_rate for fast changing signals
float _decay_rate; // decay rate for slow changing signals
float _reference; // reference value
float _gain; // current gain
float _max_gain; // maximum gain
};
#endif /* _GRI_AGC2_FF_H_ */
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