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sdrangel/wdsp/bqbp.cpp

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/* iir.c
This file is part of a program that implements a Software-Defined Radio.
Copyright (C) 2014, 2022, 2023 Warren Pratt, NR0V
Copyright (C) 2024 Edouard Griffiths, F4EXB Adapted to SDRangel
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
The author can be reached by email at
warren@wpratt.com
*/
#include "comm.hpp"
#include "bqbp.hpp"
#include "RXA.hpp"
#include "TXA.hpp"
namespace WDSP {
/********************************************************************************************************
* *
* Complex Bi-Quad Band-Pass *
* *
********************************************************************************************************/
void BQBP::calc_bqbp(BQBP *a)
{
double f0, w0, bw, q, sn, cs, c, den;
bw = a->f_high - a->f_low;
f0 = (a->f_high + a->f_low) / 2.0;
q = f0 / bw;
w0 = TWOPI * f0 / a->rate;
sn = sin(w0);
cs = cos(w0);
c = sn / (2.0 * q);
den = 1.0 + c;
a->a0 = +c / den;
a->a1 = 0.0;
a->a2 = -c / den;
a->b1 = 2.0 * cs / den;
a->b2 = (c - 1.0) / den;
flush_bqbp(a);
}
BQBP* BQBP::create_bqbp(int run, int size, float* in, float* out, double rate, double f_low, double f_high, double gain, int nstages)
{
BQBP *a = new BQBP;
a->run = run;
a->size = size;
a->in = in;
a->out = out;
a->rate = rate;
a->f_low = f_low;
a->f_high = f_high;
a->gain = gain;
a->nstages = nstages;
a->x0 = new double[a->nstages * 2]; // (float*)malloc0(a->nstages * sizeof(complex));
a->x1 = new double[a->nstages * 2]; // (float*)malloc0(a->nstages * sizeof(complex));
a->x2 = new double[a->nstages * 2]; // (float*)malloc0(a->nstages * sizeof(complex));
a->y0 = new double[a->nstages * 2]; // (float*)malloc0(a->nstages * sizeof(complex));
a->y1 = new double[a->nstages * 2]; // (float*)malloc0(a->nstages * sizeof(complex));
a->y2 = new double[a->nstages * 2]; // (float*)malloc0(a->nstages * sizeof(complex));
calc_bqbp(a);
return a;
}
void BQBP::destroy_bqbp(BQBP *a)
{
delete[](a->y2);
delete[](a->y1);
delete[](a->y0);
delete[](a->x2);
delete[](a->x1);
delete[](a->x0);
delete(a);
}
void BQBP::flush_bqbp(BQBP *a)
{
int i;
for (i = 0; i < a->nstages; i++)
{
a->x1[2 * i + 0] = a->x2[2 * i + 0] = a->y1[2 * i + 0] = a->y2[2 * i + 0] = 0.0;
a->x1[2 * i + 1] = a->x2[2 * i + 1] = a->y1[2 * i + 1] = a->y2[2 * i + 1] = 0.0;
}
}
void BQBP::xbqbp(BQBP *a)
{
if (a->run)
{
int i, j, n;
for (i = 0; i < a->size; i++)
{
for (j = 0; j < 2; j++)
{
a->x0[j] = a->gain * a->in[2 * i + j];
for (n = 0; n < a->nstages; n++)
{
if (n > 0)
a->x0[2 * n + j] = a->y0[2 * (n - 1) + j];
a->y0[2 * n + j] = a->a0 * a->x0[2 * n + j]
+ a->a1 * a->x1[2 * n + j]
+ a->a2 * a->x2[2 * n + j]
+ a->b1 * a->y1[2 * n + j]
+ a->b2 * a->y2[2 * n + j];
a->y2[2 * n + j] = a->y1[2 * n + j];
a->y1[2 * n + j] = a->y0[2 * n + j];
a->x2[2 * n + j] = a->x1[2 * n + j];
a->x1[2 * n + j] = a->x0[2 * n + j];
}
a->out[2 * i + j] = a->y0[2 * (a->nstages - 1) + j];
}
}
}
else if (a->out != a->in)
{
std::copy(a->in, a->in + a->size * 2, a->out);
}
}
void BQBP::setBuffers_bqbp(BQBP *a, float* in, float* out)
{
a->in = in;
a->out = out;
}
void BQBP::setSamplerate_bqbp(BQBP *a, int rate)
{
a->rate = rate;
calc_bqbp(a);
}
void BQBP::setSize_bqbp(BQBP *a, int size)
{
a->size = size;
flush_bqbp(a);
}
} // namespace WDSP