sdrangel/sdrbase/dsp/goertzel.h

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2.1 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2020 Jon Beniston, M7RCE //
// //
// 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_GOERTZEL_H
#define INCLUDE_GOERTZEL_H
#include <complex>
#include "export.h"
// Goertzel filter for calculting discrete Fourier transform for a single frequency
// Implementation supports non-integer multiples of fundamental frequency, see:
// https://asp-eurasipjournals.springeropen.com/track/pdf/10.1186/1687-6180-2012-56.pdf
class SDRBASE_API Goertzel
{
public:
Goertzel(double frequency, int sampleRate);
void reset();
void filter(double sample);
std::complex<double> goertzel(double lastSample);
double mag();
double phase();
int size() { return m_sampleCount; }
private:
double m_s0, m_s1, m_s2;
double m_a, m_b;
std::complex<double> m_c, m_z;
int m_sampleCount;
};
#endif // INCLUDE_GOERTZEL_H