GNU Radio v3.6.2-149-ga6d285d9 C++ API
agc.h
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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2006,2012 Free Software Foundation, Inc.
00004  *
00005  * This file is part of GNU Radio
00006  *
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 3, or (at your option)
00010  * any later version.
00011  *
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 51 Franklin Street,
00020  * Boston, MA 02110-1301, USA.
00021  */
00022 
00023 #ifndef INCLUDED_ANALOG_AGC_H
00024 #define INCLUDED_ANALOG_AGC_H
00025 
00026 #include <analog/api.h>
00027 #include <gr_complex.h>
00028 #include <math.h>
00029 
00030 namespace gr {
00031   namespace analog {
00032     namespace kernel {
00033 
00034       /*!
00035        * \brief high performance Automatic Gain Control class for complex signals.
00036        *
00037        * For Power the absolute value of the complex number is used.
00038        */
00039       class ANALOG_API agc_cc
00040       {
00041       public:
00042         agc_cc(float rate = 1e-4, float reference = 1.0,
00043                float gain = 1.0, float max_gain = 0.0)
00044           : _rate(rate), _reference(reference),
00045           _gain(gain), _max_gain(max_gain) {};
00046 
00047         virtual ~agc_cc() {};
00048 
00049         float rate() const      { return _rate; }
00050         float reference() const { return _reference; }
00051         float gain() const      { return _gain;  }
00052         float max_gain() const   { return _max_gain; }
00053 
00054         void set_rate(float rate) { _rate = rate; }
00055         void set_reference(float reference) { _reference = reference; }
00056         void set_gain(float gain) { _gain = gain; }
00057         void set_max_gain(float max_gain) { _max_gain = max_gain; }
00058 
00059         gr_complex scale(gr_complex input)
00060         {
00061           gr_complex output = input * _gain;
00062 
00063           _gain +=  _rate * (_reference - sqrt(output.real()*output.real() +
00064                                                output.imag()*output.imag()));
00065           if(_max_gain > 0.0 && _gain > _max_gain) {
00066             _gain = _max_gain;
00067           }
00068           return output;
00069         }
00070 
00071         void scaleN(gr_complex output[], const gr_complex input[], unsigned n)
00072         {
00073           for(unsigned i = 0; i < n; i++) {
00074             output[i] = scale (input[i]);
00075           }
00076         }
00077 
00078       protected:
00079         float _rate;            // adjustment rate
00080         float _reference;       // reference value
00081         float _gain;            // current gain
00082         float _max_gain;        // max allowable gain
00083       };
00084 
00085       /*!
00086        * \brief high performance Automatic Gain Control class for float signals.
00087        *
00088        * Power is approximated by absolute value
00089        */
00090       class ANALOG_API agc_ff 
00091       {
00092       public:
00093         agc_ff(float rate = 1e-4, float reference = 1.0,
00094                float gain = 1.0, float max_gain = 0.0)
00095           : _rate(rate), _reference(reference), _gain(gain),
00096           _max_gain(max_gain) {};
00097 
00098         ~agc_ff() {};
00099 
00100         float rate () const      { return _rate; }
00101         float reference () const { return _reference; }
00102         float gain () const      { return _gain;  }
00103         float max_gain () const  { return _max_gain; }
00104 
00105         void set_rate (float rate) { _rate = rate; }
00106         void set_reference (float reference) { _reference = reference; }
00107         void set_gain (float gain) { _gain = gain; }
00108         void set_max_gain (float max_gain) { _max_gain = max_gain; }
00109 
00110         float scale (float input)
00111         {
00112           float output = input * _gain;
00113           _gain += (_reference - fabsf (output)) * _rate;
00114           if(_max_gain > 0.0 && _gain > _max_gain)
00115             _gain = _max_gain;
00116           return output;
00117         }
00118 
00119         void scaleN(float output[], const float input[], unsigned n)
00120         {
00121           for(unsigned i = 0; i < n; i++)
00122             output[i] = scale (input[i]);
00123         }
00124 
00125       protected:
00126         float _rate;            // adjustment rate
00127         float _reference;       // reference value
00128         float _gain;            // current gain
00129         float _max_gain;        // maximum gain
00130       };
00131 
00132     } /* namespace kernel */
00133   } /* namespace analog */
00134 } /* namespace gr */
00135 
00136 #endif /* INCLUDED_ANALOG_AGC_H */