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88 lines
2.8 KiB
C
88 lines
2.8 KiB
C
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///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2015 Edouard Griffiths, F4EXB. //
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// //
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////
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#ifndef INCLUDE_GPL_DSP_AFSQUELCH_H_
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#define INCLUDE_GPL_DSP_AFSQUELCH_H_
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#include "dsp/dsptypes.h"
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/** AFSquelch: AF squelch class based on the Modified Goertzel
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* algorithm.
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*/
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class AFSquelch {
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public:
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// Constructors and Destructor
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AFSquelch();
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// allows user defined tone pair
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AFSquelch(unsigned int nbTones, const Real *tones);
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virtual ~AFSquelch();
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// setup the basic parameters and coefficients
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void setCoefficients(
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int N, // the algorithm "block" size
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int SampleRate, // input signal sample rate
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int _samplesAttack, // number of results before squelch opens
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int _samplesDecay); // number of results keeping squelch open
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// set the detection threshold
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void setThreshold(double _threshold) {
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threshold = _threshold;
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}
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// analyze a sample set and optionally filter
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// the tone frequencies.
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bool analyze(Real *sample); // input signal sample
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// get the tone set
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const Real *getToneSet() const
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{
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return toneSet;
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}
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bool open() const {
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return isOpen;
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}
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void reset(); // reset the analysis algorithm
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protected:
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void feedback(Real sample);
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void feedForward();
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void evaluate();
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private:
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int N;
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int sampleRate;
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int samplesProcessed;
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int maxPowerIndex;
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int nTones;
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int samplesAttack;
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int attackCount;
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int samplesDecay;
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int decayCount;
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bool isOpen;
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double threshold;
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double *k;
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double *coef;
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Real *toneSet;
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double *u0;
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double *u1;
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double *power;
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};
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#endif /* INCLUDE_GPL_DSP_CTCSSDETECTOR_H_ */
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