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157 lines
3.7 KiB
C++
157 lines
3.7 KiB
C++
/* dbqbp.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 "dbqbp.hpp"
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namespace WDSP {
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/********************************************************************************************************
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* *
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* Double Bi-Quad Band-Pass *
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* *
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********************************************************************************************************/
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void DBQBP::calc()
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{
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double f0;
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double w0;
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double bw;
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double q;
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double sn;
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double cs;
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double c;
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double den;
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bw = f_high - f_low;
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f0 = (f_high + f_low) / 2.0;
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q = f0 / bw;
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w0 = TWOPI * f0 / rate;
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sn = sin(w0);
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cs = cos(w0);
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c = sn / (2.0 * q);
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den = 1.0 + c;
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a0 = +c / den;
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a1 = 0.0;
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a2 = -c / den;
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b1 = 2.0 * cs / den;
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b2 = (c - 1.0) / den;
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flush();
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}
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DBQBP::DBQBP(
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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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double _rate,
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double _f_low,
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double _f_high,
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double _gain,
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int _nstages
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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_low(_f_low),
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f_high(_f_high),
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gain(_gain),
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nstages(_nstages)
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{
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x0.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
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x1.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
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x2.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
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y0.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
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y1.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
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y2.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
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calc();
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}
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void DBQBP::flush()
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{
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for (int i = 0; i < nstages; i++)
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{
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x1[i] = x2[i] = y1[i] = y2[i] = 0.0;
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}
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}
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void DBQBP::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[0] = gain * in[i];
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for (int n = 0; n < nstages; n++)
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{
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if (n > 0)
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x0[n] = y0[n - 1];
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y0[n] = a0 * x0[n]
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+ a1 * x1[n]
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+ a2 * x2[n]
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+ b1 * y1[n]
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+ b2 * y2[n];
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y2[n] = y1[n];
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y1[n] = y0[n];
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x2[n] = x1[n];
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x1[n] = x0[n];
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}
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out[i] = (float) y0[nstages - 1];
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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, out);
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}
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}
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void DBQBP::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 DBQBP::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 DBQBP::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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} // namespace WDSP
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