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sdrangel/sdrbase/dsp/afsquelch.h
2016-03-08 04:54:12 +01:00

91 lines
3.1 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2015 Edouard Griffiths, F4EXB. //
// //
// This program 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 as version 3 of the License, or //
// //
// This program 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 V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#ifndef INCLUDE_GPL_DSP_AFSQUELCH_H_
#define INCLUDE_GPL_DSP_AFSQUELCH_H_
#include "dsp/dsptypes.h"
#include "dsp/movingaverage.h"
/** AFSquelch: AF squelch class based on the Modified Goertzel
* algorithm.
*/
class AFSquelch {
public:
// Constructors and Destructor
AFSquelch();
// allows user defined tone pair
AFSquelch(unsigned int nbTones,
const Real *tones);
virtual ~AFSquelch();
// setup the basic parameters and coefficients
void setCoefficients(
int N, //!< the algorithm "block" size
unsigned int nbAvg, //!< averaging size
int SampleRate, //!< input signal sample rate
int _samplesAttack, //!< number of results before squelch opens
int _samplesDecay); //!< number of results keeping squelch open
// set the detection threshold
void setThreshold(double _threshold);
// analyze a sample set and optionally filter
// the tone frequencies.
bool analyze(Real sample); // input signal sample
bool evaluate(); // evaluate result
// get the tone set
const Real *getToneSet() const
{
return m_toneSet;
}
bool open() const {
return m_isOpen;
}
void reset(); // reset the analysis algorithm
protected:
void feedback(Real sample);
void feedForward();
private:
unsigned int m_nbAvg; //!< number of power samples taken for moving average
int m_N;
int m_sampleRate;
int m_samplesProcessed;
int m_maxPowerIndex;
int m_nTones;
int m_samplesAttack;
int m_attackCount;
int m_samplesDecay;
int m_decayCount;
bool m_isOpen;
double m_threshold;
double *m_k;
double *m_coef;
Real *m_toneSet;
double *m_u0;
double *m_u1;
double *m_power;
std::vector<MovingAverage<Real> > m_movingAverages;
};
#endif /* INCLUDE_GPL_DSP_CTCSSDETECTOR_H_ */