mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-22 08:04:49 -05:00
147 lines
3.6 KiB
C++
147 lines
3.6 KiB
C++
/* dbqlp.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 "dbqlp.hpp"
|
|
|
|
namespace WDSP {
|
|
|
|
/********************************************************************************************************
|
|
* *
|
|
* Double Bi-Quad Low-Pass *
|
|
* *
|
|
********************************************************************************************************/
|
|
|
|
void DBQLP::calc()
|
|
{
|
|
float w0, cs, c, den;
|
|
|
|
w0 = TWOPI * fc / (float)rate;
|
|
cs = cos(w0);
|
|
c = sin(w0) / (2.0 * Q);
|
|
den = 1.0 + c;
|
|
a0 = 0.5 * (1.0 - cs) / den;
|
|
a1 = (1.0 - cs) / den;
|
|
a2 = 0.5 * (1.0 - cs) / den;
|
|
b1 = 2.0 * cs / den;
|
|
b2 = (c - 1.0) / den;
|
|
flush();
|
|
}
|
|
|
|
DBQLP::DBQLP(
|
|
int _run,
|
|
int _size,
|
|
float* _in,
|
|
float* _out,
|
|
double _rate,
|
|
double _fc,
|
|
double _Q,
|
|
double _gain,
|
|
int _nstages
|
|
) :
|
|
run(_run),
|
|
size(_size),
|
|
in(_in),
|
|
out(_out),
|
|
rate(_rate),
|
|
fc(_fc),
|
|
Q(_Q),
|
|
gain(_gain),
|
|
nstages(_nstages)
|
|
{
|
|
x0.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
|
|
x1.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
|
|
x2.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
|
|
y0.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
|
|
y1.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
|
|
y2.resize(nstages); // (float*)malloc0(nstages * sizeof(float));
|
|
calc();
|
|
}
|
|
|
|
void DBQLP::flush()
|
|
{
|
|
for (int i = 0; i < nstages; i++)
|
|
{
|
|
x1[i] = x2[i] = y1[i] = y2[i] = 0.0;
|
|
}
|
|
}
|
|
|
|
void DBQLP::execute()
|
|
{
|
|
if (run)
|
|
{
|
|
int i, n;
|
|
|
|
for (i = 0; i < size; i++)
|
|
{
|
|
x0[0] = gain * in[i];
|
|
|
|
for (n = 0; n < nstages; n++)
|
|
{
|
|
if (n > 0)
|
|
x0[n] = y0[n - 1];
|
|
|
|
y0[n] = a0 * x0[n]
|
|
+ a1 * x1[n]
|
|
+ a2 * x2[n]
|
|
+ b1 * y1[n]
|
|
+ b2 * y2[n];
|
|
y2[n] = y1[n];
|
|
y1[n] = y0[n];
|
|
x2[n] = x1[n];
|
|
x1[n] = x0[n];
|
|
}
|
|
|
|
out[i] = y0[nstages - 1];
|
|
}
|
|
}
|
|
else if (out != in)
|
|
{
|
|
std::copy(in, in + size, out);
|
|
}
|
|
}
|
|
|
|
void DBQLP::setBuffers(float* _in, float* _out)
|
|
{
|
|
in = _in;
|
|
out = _out;
|
|
}
|
|
|
|
void DBQLP::setSamplerate(int _rate)
|
|
{
|
|
rate = _rate;
|
|
calc();
|
|
}
|
|
|
|
void DBQLP::setSize(int _size)
|
|
{
|
|
size = _size;
|
|
flush();
|
|
}
|
|
|
|
} // namespace WDSP
|