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https://github.com/f4exb/sdrangel.git
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138 lines
3.4 KiB
C++
138 lines
3.4 KiB
C++
/* iir.c
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This file is part of a program that implements a Software-Defined Radio.
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Copyright (C) 2014, 2022, 2023 Warren Pratt, NR0V
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Copyright (C) 2024 Edouard Griffiths, F4EXB Adapted to SDRangel
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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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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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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The author can be reached by email at
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warren@wpratt.com
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*/
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#include "comm.hpp"
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#include "snotch.hpp"
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namespace WDSP {
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/********************************************************************************************************
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* *
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* Bi-Quad Notch *
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* *
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********************************************************************************************************/
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void SNOTCH::calc()
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{
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double fn;
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double qk;
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double qr;
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double csn;
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fn = f / rate;
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csn = cos (TWOPI * fn);
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qr = 1.0 - 3.0 * bw;
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qk = (1.0 - 2.0 * qr * csn + qr * qr) / (2.0 * (1.0 - csn));
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a0 = + qk;
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a1 = - 2.0 * qk * csn;
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a2 = + qk;
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b1 = + 2.0 * qr * csn;
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b2 = - qr * qr;
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flush();
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}
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SNOTCH::SNOTCH(
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int _run,
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int _size,
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float* _in,
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float* _out,
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int _rate,
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double _f,
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double _bw
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) :
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run(_run),
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size(_size),
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in(_in),
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out(_out),
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rate(_rate),
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f(_f),
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bw(_bw)
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{
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calc();
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}
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void SNOTCH::flush()
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{
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x1 = x2 = y1 = y2 = 0.0;
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}
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void SNOTCH::execute()
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{
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if (run)
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{
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for (int i = 0; i < size; i++)
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{
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x0 = in[2 * i + 0];
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out[2 * i + 0] = (float) (a0 * x0 + a1 * x1 + a2 * x2 + b1 * y1 + b2 * y2);
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y2 = y1;
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y1 = out[2 * i + 0];
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x2 = x1;
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x1 = x0;
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}
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}
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else if (out != in)
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{
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std::copy( in, in + size * 2, out);
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}
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}
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void SNOTCH::setBuffers(float* _in, float* _out)
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{
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in = _in;
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out = _out;
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}
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void SNOTCH::setSamplerate(int _rate)
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{
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rate = _rate;
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calc();
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}
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void SNOTCH::setSize(int _size)
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{
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size = _size;
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flush();
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}
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/********************************************************************************************************
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* *
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* RXA Properties *
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* *
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********************************************************************************************************/
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void SNOTCH::setFreq(double _freq)
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{
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f = _freq;
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calc();
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}
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void SNOTCH::setRun(int _run)
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{
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run = _run;
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}
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} // namespace WDSP
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