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73 lines
2.5 KiB
C++
73 lines
2.5 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2017 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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#include <math.h>
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#include "recursivefilters.h"
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#undef M_PI
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#define M_PI 3.14159265358979323846
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SecondOrderRecursiveFilter::SecondOrderRecursiveFilter(float samplingFrequency, float centerFrequency, float r) :
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m_r(r),
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m_frequencyRatio(centerFrequency/samplingFrequency)
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{
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init();
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}
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SecondOrderRecursiveFilter::~SecondOrderRecursiveFilter()
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{}
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void SecondOrderRecursiveFilter::setFrequencies(float samplingFrequency, float centerFrequency)
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{
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m_frequencyRatio = centerFrequency / samplingFrequency;
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init();
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}
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void SecondOrderRecursiveFilter::setR(float r)
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{
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m_r = r;
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init();
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}
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short SecondOrderRecursiveFilter::run(short sample)
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{
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m_v[0] = ((1.0f - m_r) * (float) sample) + (2.0f * m_r * cos(2.0*M_PI*m_frequencyRatio) * m_v[1]) - (m_r * m_r * m_v[2]);
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float y = m_v[0] - m_v[2];
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m_v[2] = m_v[1];
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m_v[1] = m_v[0];
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return (short) y;
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}
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float SecondOrderRecursiveFilter::run(float sample)
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{
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m_v[0] = ((1.0f - m_r) * sample) + (2.0f * m_r * cos(2.0*M_PI*m_frequencyRatio) * m_v[1]) - (m_r * m_r * m_v[2]);
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float y = m_v[0] - m_v[2];
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m_v[2] = m_v[1];
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m_v[1] = m_v[0];
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return y;
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}
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void SecondOrderRecursiveFilter::init()
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{
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for (int i = 0; i < 3; i++)
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{
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m_v[i] = 0.0f;
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}
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}
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