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sdrangel/sdrbase/dsp/ctcssdetector.h
2020-11-14 11:13:32 +01:00

95 lines
3.7 KiB
C++

//////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2015-2020 Edouard Griffiths, F4EXB //
// //
// See: http://www.embedded.com/design/connectivity/4025660/Detecting-CTCSS-tones-with-Goertzel-s-algorithm //
// //
// 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 //
// (at your option) any later version. //
// //
// 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_CTCSSDETECTOR_H_
#define INCLUDE_GPL_DSP_CTCSSDETECTOR_H_
#include "dsp/dsptypes.h"
#include "export.h"
#include "ctcssfrequencies.h"
/** CTCSSDetector: Continuous Tone Coded Squelch System
* tone detector class based on the Modified Goertzel
* algorithm.
*/
class SDRBASE_API CTCSSDetector {
public:
CTCSSDetector();
virtual ~CTCSSDetector();
// setup the basic parameters and coefficients
void setCoefficients(
int N, // the algorithm "block" size
int sampleRate // input signal sample rate
);
// set the detection threshold
void setThreshold(double thold);
// analyze a sample set and optionally filter the tone frequencies.
bool analyze(Real *sample); // input signal sample
// get the number of defined tones.
int getNTones() const {
return CTCSSFrequencies::m_nbFreqs;
}
// get the tone set
const Real *getToneSet() const {
return CTCSSFrequencies::m_Freqs;
}
// get the currently detected tone, if any
bool getDetectedTone(int &maxTone) const
{
maxTone = m_maxPowerIndex;
return m_toneDetected;
}
// Get the max m_power at the detected tone.
Real getMaxPower() const {
return m_maxPower;
}
void reset(); // reset the analysis algorithm
protected:
// Override these to change behavior of the detector
virtual void initializePower();
virtual void evaluatePower();
void feedback(Real sample);
void feedForward();
private:
int m_N;
int m_sampleRate;
int m_samplesProcessed;
int m_maxPowerIndex;
bool m_toneDetected;
Real m_maxPower;
Real *m_k;
Real *m_coef;
Real *m_u0;
Real *m_u1;
Real *m_power;
};
#endif /* INCLUDE_GPL_DSP_CTCSSDETECTOR_H_ */