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sdrangel/include-gpl/dsp/ctcssdetector.h

89 lines
2.0 KiB
C++

/*
* ctcssdetector.h
*
* Created on: Jun 16, 2015
* Author: f4exb
* See: http://www.embedded.com/design/connectivity/4025660/Detecting-CTCSS-tones-with-Goertzel-s-algorithm
*/
#ifndef INCLUDE_GPL_DSP_CTCSSDETECTOR_H_
#define INCLUDE_GPL_DSP_CTCSSDETECTOR_H_
#include "dsp/dsptypes.h"
/** CTCSSDetector: Continuous Tone Coded Squelch System
* tone detector class based on the Modified Goertzel
* algorithm.
*/
class CTCSSDetector {
public:
// Constructors and Destructor
CTCSSDetector();
// allows user defined CTCSS tone set
CTCSSDetector(int _nTones, Real *tones);
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 nTones;
}
// get the tone set
const Real *getToneSet() const
{
return toneSet;
}
// get the currently detected tone, if any
bool getDetectedTone(int &maxTone) const
{
maxTone = maxPowerIndex;
return toneDetected;
}
// Get the max power at the detected tone.
Real getMaxPower() const
{
return 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 N;
int sampleRate;
int nTones;
int samplesProcessed;
int maxPowerIndex;
bool toneDetected;
Real maxPower;
Real *k;
Real *coef;
Real *toneSet;
Real *u0;
Real *u1;
Real *power;
};
#endif /* INCLUDE_GPL_DSP_CTCSSDETECTOR_H_ */