/* fmd.c
This file is part of a program that implements a Software-Defined Radio.
Copyright (C) 2013, 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 <array>
#include "comm.hpp"
#include "fircore.hpp"
#include "fcurve.hpp"
#include "fir.hpp"
#include "wcpAGC.hpp"
#include "snotch.hpp"
#include "fmd.hpp"
namespace WDSP {
void FMD::calc()
{
// pll
omega_min = TWOPI * fmin / rate;
omega_max = TWOPI * fmax / rate;
g1 = 1.0 - exp(-2.0 * omegaN * zeta / rate);
g2 = -g1 + 2.0 * (1 - exp(-omegaN * zeta / rate) * cos(omegaN / rate * sqrt(1.0 - zeta * zeta)));
phs = 0.0;
fil_out = 0.0;
omega = 0.0;
pllpole = omegaN * sqrt(2.0 * zeta * zeta + 1.0 + sqrt((2.0 * zeta * zeta + 1.0) * (2.0 * zeta * zeta + 1.0) + 1)) / TWOPI;
// dc removal
mtau = exp(-1.0 / (rate * tau));
onem_mtau = 1.0 - mtau;
fmdc = 0.0;
// pll audio gain
again = rate / (deviation * TWOPI);
// CTCSS Removal
sntch = new SNOTCH(
1,
size,
out,
out,
(int) rate,
ctcss_freq,
0.0002)
;
// detector limiter
plim = new WCPAGC(
1, // run - always ON
5, // mode
1, // 0 for max(I,Q), 1 for envelope
out, // input buff pointer
out, // output buff pointer
size, // io_buffsize
(int)rate, // sample rate
0.001, // tau_attack
0.008, // tau_decay
4, // n_tau
lim_gain, // max_gain (sets threshold, initial value)
1.0, // var_gain / slope
1.0, // fixed_gain
1.0, // max_input
0.9, // out_targ
0.250, // tau_fast_backaverage
0.004, // tau_fast_decay
4.0, // pop_ratio
0, // hang_enable
0.500, // tau_hang_backmult
0.500, // hangtime
2.000, // hang_thresh
0.100); // tau_hang_decay
}
void FMD::decalc()
{
delete plim;
delete sntch;
}
FMD::FMD(
int _run,
int _size,
float* _in,
float* _out,
int _rate,
double _deviation,
double _f_low,
double _f_high,
double _fmin,
double _fmax,
double _zeta,
double _omegaN,
double _tau,
double _afgain,
int _sntch_run,
double _ctcss_freq,
int _nc_de,
int _mp_de,
int _nc_aud,
int _mp_aud
) :
run(_run),
size(_size),
in(_in),
out(_out),
rate((double) _rate),
f_low(_f_low),
f_high(_f_high),
fmin(_fmin),
fmax(_fmax),
zeta(_zeta),
omegaN(_omegaN),
tau(_tau),
deviation(_deviation),
nc_de(_nc_de),
mp_de(_mp_de),
nc_aud(_nc_aud),
mp_aud(_mp_aud),
afgain(_afgain),
sntch_run(_sntch_run),
ctcss_freq(_ctcss_freq),
lim_run(0),
lim_gain(0.0001), // 2.5
lim_pre_gain(0.01) // 0.4
{
calc();
// de-emphasis filter
audio.resize(size * 2);
std::vector<float> impulse(2 * nc_de);
FCurve::fc_impulse (
impulse,
nc_de,
(float) f_low,
(float) f_high,
(float) (+20.0 * log10(f_high / f_low)),
0.0, 1,
(float) rate,
(float) (1.0 / (2.0 * size)),
0,
0
);
pde = new FIRCORE(size, audio.data(), out, mp_de, impulse);
// audio filter
std::vector<float> impulseb;
FIR::fir_bandpass(impulseb, nc_aud, 0.8 * f_low, 1.1 * f_high, rate, 0, 1, afgain / (2.0 * size));
paud = new FIRCORE(size, out, out, mp_aud, impulseb);
}
FMD::~FMD()
{
delete paud;
delete pde;
decalc();
}
void FMD::flush()
{
std::fill(audio.begin(), audio.end(), 0);
pde->flush();
paud->flush();
phs = 0.0;
fil_out = 0.0;
omega = 0.0;
fmdc = 0.0;
sntch->flush();
plim->flush();
}
void FMD::execute()
{
if (run)
{
int i;
double det;
double del_out;
std::array<double, 2> vco;
std::array<double, 2> corr;
for (i = 0; i < size; i++)
{
// pll
vco[0] = cos (phs);
vco[1] = sin (phs);
corr[0] = + in[2 * i + 0] * vco[0] + in[2 * i + 1] * vco[1];
corr[1] = - in[2 * i + 0] * vco[1] + in[2 * i + 1] * vco[0];
if ((corr[0] == 0.0) && (corr[1] == 0.0)) corr[0] = 1.0;
det = atan2 (corr[1], corr[0]);
del_out = fil_out;
omega += g2 * det;
if (omega < omega_min) omega = omega_min;
if (omega > omega_max) omega = omega_max;
fil_out = g1 * det + omega;
phs += del_out;
while (phs >= TWOPI) phs -= TWOPI;
while (phs < 0.0) phs += TWOPI;
// dc removal, gain, & demod output
fmdc = mtau * fmdc + onem_mtau * fil_out;
audio[2 * i + 0] = (float) (again * (fil_out - fmdc));
audio[2 * i + 1] = audio[2 * i + 0];
}
// de-emphasis
pde->execute();
// audio filter
paud->execute();
// CTCSS Removal
sntch->execute();
if (lim_run)
{
for (i = 0; i < 2 * size; i++)
out[i] *= (float) lim_pre_gain;
plim->execute();
}
}
else if (in != out)
std::copy( in, in + size * 2, out);
}
void FMD::setBuffers(float* _in, float* _out)
{
decalc();
in = _in;
out = _out;
calc();
pde->setBuffers(audio.data(), out);
paud->setBuffers(out, out);
plim->setBuffers(out, out);
}
void FMD::setSamplerate(int _rate)
{
decalc();
rate = _rate;
calc();
// de-emphasis filter
std::vector<float> impulse(2 * nc_de);
FCurve::fc_impulse (
impulse,
nc_de,
(float) f_low,
(float) f_high,
(float) (+20.0 * log10(f_high / f_low)),
0.0,
1,
(float) rate,
(float) (1.0 / (2.0 * size)),
0,
0
);
pde->setImpulse(impulse, 1);
// audio filter
std::vector<float> impulseb;
FIR::fir_bandpass(impulseb, nc_aud, 0.8 * f_low, 1.1 * f_high, rate, 0, 1, afgain / (2.0 * size));
paud->setImpulse(impulseb, 1);
plim->setSamplerate((int) rate);
}
void FMD::setSize(int _size)
{
decalc();
size = _size;
calc();
audio.resize(size * 2);
// de-emphasis filter
delete pde;
std::vector<float> impulse(2 * nc_de);
FCurve::fc_impulse (
impulse,
nc_de,
(float) f_low,
(float) f_high,
(float) (+20.0 * log10(f_high / f_low)),
0.0,
1,
(float) rate,
(float) (1.0 / (2.0 * size)),
0,
0
);
pde = new FIRCORE(size, audio.data(), out, mp_de, impulse);
// audio filter
delete paud;
std::vector<float> impulseb;
FIR::fir_bandpass(impulseb, nc_aud, 0.8 * f_low, 1.1 * f_high, rate, 0, 1, afgain / (2.0 * size));
paud = new FIRCORE(size, out, out, mp_aud, impulseb);
plim->setSize(size);
}
/********************************************************************************************************
* *
* RXA Properties *
* *
********************************************************************************************************/
void FMD::setDeviation(double _deviation)
{
deviation = _deviation;
again = rate / (deviation * TWOPI);
}
void FMD::setCTCSSFreq(double freq)
{
ctcss_freq = freq;
sntch->setFreq(ctcss_freq);
}
void FMD::setCTCSSRun(int _run)
{
sntch_run = _run;
sntch->setRun(sntch_run);
}
void FMD::setNCde(int nc)
{
if (nc_de != nc)
{
nc_de = nc;
std::vector<float> impulse(2 * nc_de);
FCurve::fc_impulse (
impulse,
nc_de,
(float) f_low,
(float) f_high,
(float) (+20.0 * log10(f_high / f_low)),
0.0,
1,
(float) rate,
(float) (1.0 / (2.0 * size)),
0,
0
);
pde->setNc(impulse);
}
}
void FMD::setMPde(int mp)
{
if (mp_de != mp)
{
mp_de = mp;
pde->setMp(mp_de);
}
}
void FMD::setNCaud(int nc)
{
if (nc_aud != nc)
{
nc_aud = nc;
std::vector<float> impulse;
FIR::fir_bandpass(impulse, nc_aud, 0.8 * f_low, 1.1 * f_high, rate, 0, 1, afgain / (2.0 * size));
paud->setNc(impulse);
}
}
void FMD::setMPaud(int mp)
{
if (mp_aud != mp)
{
mp_aud = mp;
paud->setMp(mp_aud);
}
}
void FMD::setLimRun(int _run)
{
if (lim_run != _run) {
lim_run = _run;
}
}
void FMD::setLimGain(double gaindB)
{
double gain = pow(10.0, gaindB / 20.0);
if (lim_gain != gain)
{
decalc();
lim_gain = gain;
calc();
}
}
void FMD::setAFFilter(double low, double high)
{
if (f_low != low || f_high != high)
{
f_low = low;
f_high = high;
// de-emphasis filter
std::vector<float> impulse(2 * nc_de);
FCurve::fc_impulse (
impulse,
nc_de,
(float) f_low,
(float) f_high,
(float) (+20.0 * log10(f_high / f_low)),
0.0,
1,
(float) rate,
(float) (1.0 / (2.0 * size)),
0,
0
);
pde->setImpulse(impulse, 1);
// audio filter
std::vector<float> impulseb;
FIR::fir_bandpass (impulseb, nc_aud, 0.8 * f_low, 1.1 * f_high, rate, 0, 1, afgain / (2.0 * size));
paud->setImpulse(impulseb, 1);
}
}
} // namespace WDSP