GNU Radio 3.6.2 C++ API
gri_agc_ff.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2002,2006 Free Software Foundation, Inc.
4  *
5  * This file is part of GNU Radio
6  *
7  * GNU Radio is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 3, or (at your option)
10  * any later version.
11  *
12  * GNU Radio is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with GNU Radio; see the file COPYING. If not, write to
19  * the Free Software Foundation, Inc., 51 Franklin Street,
20  * Boston, MA 02110-1301, USA.
21  */
22 
23 #ifndef INCLUDED_GRI_AGC_FF_H
24 #define INCLUDED_GRI_AGC_FF_H
25 
26 #include <gr_core_api.h>
27 #include <math.h>
28 
29 /*!
30  * \brief high performance Automatic Gain Control class
31  *
32  * Power is approximated by absolute value
33  */
35 
36  public:
37  gri_agc_ff (float rate = 1e-4, float reference = 1.0,
38  float gain = 1.0, float max_gain = 0.0)
39  : _rate(rate), _reference(reference), _gain(gain), _max_gain(max_gain) {};
40 
41  float rate () const { return _rate; }
42  float reference () const { return _reference; }
43  float gain () const { return _gain; }
44  float max_gain () const { return _max_gain; }
45 
46  void set_rate (float rate) { _rate = rate; }
47  void set_reference (float reference) { _reference = reference; }
48  void set_gain (float gain) { _gain = gain; }
49  void set_max_gain (float max_gain) { _max_gain = max_gain; }
50 
51  float scale (float input){
52  float output = input * _gain;
53  _gain += (_reference - fabsf (output)) * _rate;
54  if (_max_gain > 0.0 && _gain > _max_gain)
55  _gain = _max_gain;
56  return output;
57  }
58 
59  void scaleN (float output[], const float input[], unsigned n){
60  for (unsigned i = 0; i < n; i++)
61  output[i] = scale (input[i]);
62  }
63 
64  protected:
65  float _rate; // adjustment rate
66  float _reference; // reference value
67  float _gain; // current gain
68  float _max_gain; // maximum gain
69 };
70 
71 #endif /* INCLUDED_GRI_AGC_FF_H */
72