60 lines
1.6 KiB
C++
60 lines
1.6 KiB
C++
/*
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* Copyright (C) 2015-2020 by Jonathan Naylor G4KLX
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* Copyright (C) 2020 by Geoffrey Merck - F4FXL KC3FRA
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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; either version 2 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 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, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "IIRDirectForm1Filter.h"
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#include "math.h"
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CIIRDirectForm1Filter::CIIRDirectForm1Filter(float b0, float b1, float b2, float , float a1, float a2, float addtionalGaindB) :
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m_x2(0.0F),
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m_y2(0.0F),
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m_x1(0.0F),
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m_y1(0.0F),
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m_b0(b0),
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m_b1(b1),
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m_b2(b2),
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m_a1(a1),
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m_a2(a2),
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m_additionalGainLin(0.0F)
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{
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m_additionalGainLin = ::powf(10.0F, addtionalGaindB / 20.0F);
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}
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float CIIRDirectForm1Filter::filter(float sample)
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{
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float output = m_b0 * sample
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+ m_b1 * m_x1
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+ m_b2 * m_x2
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- m_a1 * m_y1
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- m_a2 * m_y2;
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m_x2 = m_x1;
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m_y2 = m_y1;
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m_x1 = sample;
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m_y1 = output;
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return output * m_additionalGainLin;
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}
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void CIIRDirectForm1Filter::reset()
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{
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m_x1 = 0.0f;
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m_x2 = 0.0f;
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m_y1 = 0.0f;
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m_y2 = 0.0f;
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}
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