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75 lines
2.5 KiB
C++
75 lines
2.5 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
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// written by Christian Daniel //
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// Copyright (C) 2015-2019 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
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// Copyright (C) 2020 Jon Beniston, M7RCE <jon@beniston.com> //
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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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// (at your option) any later version. //
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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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#include "goertzel.h"
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Goertzel::Goertzel(double frequency, int sampleRate) :
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m_s0(0.0),
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m_s1(0.0),
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m_s2(0.0),
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m_z(0.0),
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m_sampleCount(0)
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{
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m_a = 2.0 * M_PI * frequency / sampleRate;
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m_b = 2.0 * cos(m_a);
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m_c = std::complex<double>(cos(-m_a), sin(-m_a));
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}
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void Goertzel::reset()
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{
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m_s0 = 0.0;
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m_s1 = 0.0;
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m_s2 = 0.0;
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m_z = 0.0;
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m_sampleCount = 0;
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}
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void Goertzel::filter(double sample)
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{
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m_s0 = m_b * m_s1 - m_s2 + sample;
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m_s2 = m_s1;
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m_s1 = m_s0;
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m_sampleCount++;
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}
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std::complex<double> Goertzel::goertzel(double lastSample)
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{
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m_s0 = m_b * m_s1 - m_s2 + lastSample;
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m_sampleCount++;
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std::complex<double> y = m_s0 - m_s1 * m_c;
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double x = -m_a * (m_sampleCount - 1.0);
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std::complex<double> d(cos(x), sin(x));
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double scale = m_sampleCount / 2.0;
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m_z = y * d / scale;
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return m_z;
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}
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double Goertzel::mag()
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{
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return std::abs(m_z);
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}
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double Goertzel::phase()
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{
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return std::arg(m_z);
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}
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