sdrangel/wdsp/ssql.cpp

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C++

/* ssql.c
This file is part of a program that implements a Software-Defined Radio.
Copyright (C) 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@pratt.one
*/
#include "comm.hpp"
#include "cblock.hpp"
#include "ssql.hpp"
#include "iir.hpp"
#include "RXA.hpp"
namespace WDSP {
/********************************************************************************************************
* *
* Frequency to Voltage Converter *
* *
********************************************************************************************************/
FTOV* FTOV::create_ftov (int run, int size, int rate, int rsize, double fmax, float* in, float* out)
{
FTOV *a = new FTOV;
a->run = run;
a->size = size;
a->rate = rate;
a->rsize = rsize;
a->fmax = fmax;
a->in = in;
a->out = out;
a->eps = 0.01;
a->ring = new int[a->rsize]; // (int*) malloc0 (a->rsize * sizeof (int));
a->rptr = 0;
a->inlast = 0.0;
a->rcount = 0;
a->div = a->fmax * 2.0 * a->rsize / a->rate; // fmax * 2 = zero-crossings/sec
// rsize / rate = sec of data in ring
// product is # zero-crossings in ring at fmax
return a;
}
void FTOV::destroy_ftov (FTOV *a)
{
delete[] (a->ring);
delete (a);
}
void FTOV::flush_ftov (FTOV *a)
{
memset (a->ring, 0, a->rsize * sizeof (int));
a->rptr = 0;
a->rcount = 0;
a->inlast = 0.0;
}
void FTOV::xftov (FTOV *a)
{
// 'ftov' does frequency to voltage conversion looking only at zero crossings of an
// AC (DC blocked) signal, i.e., ignoring signal amplitude.
if (a->run)
{
if (a->ring[a->rptr] == 1) // if current ring location is a '1' ...
{
a->rcount--; // decrement the count
a->ring[a->rptr] = 0; // set the location to '0'
}
if ((a->inlast * a->in[0] < 0.0) && // different signs mean zero-crossing
(fabs (a->inlast - a->in[0]) > a->eps))
{
a->ring[a->rptr] = 1; // set the ring location to '1'
a->rcount++; // increment the count
}
if (++a->rptr == a->rsize) a->rptr = 0; // increment and wrap the pointer as needed
a->out[0] = std::min (1.0, (double)a->rcount / a->div); // calculate the output sample
a->inlast = a->in[a->size - 1]; // save the last input sample for next buffer
for (int i = 1; i < a->size; i++)
{
if (a->ring[a->rptr] == 1) // if current ring location is '1' ...
{
a->rcount--; // decrement the count
a->ring[a->rptr] = 0; // set the location to '0'
}
if ((a->in[i - 1] * a->in[i] < 0.0) && // different signs mean zero-crossing
(fabs (a->in[i - 1] - a->in[i]) > a->eps))
{
a->ring[a->rptr] = 1; // set the ring location to '1'
a->rcount++; // increment the count
}
if (++a->rptr == a->rsize) a->rptr = 0; // increment and wrap the pointer as needed
a->out[i] = std::min(1.0, (double)a->rcount / a->div); // calculate the output sample
}
}
}
/*******************************************************************************************************/
/********************************** END Frequency to Voltage Converter *********************************/
void SSQL::compute_ssql_slews(SSQL *a)
{
int i;
double delta, theta;
delta = PI / (double)a->ntup;
theta = 0.0;
for (i = 0; i <= a->ntup; i++)
{
a->cup[i] = a->muted_gain + (1.0 - a->muted_gain) * 0.5 * (1.0 - cos(theta));
theta += delta;
}
delta = PI / (double)a->ntdown;
theta = 0.0;
for (i = 0; i <= a->ntdown; i++)
{
a->cdown[i] = a->muted_gain + (1.0 - a->muted_gain) * 0.5 * (1.0 + cos(theta));
theta += delta;
}
}
void SSQL::calc_ssql (SSQL *a)
{
a->b1 = new float[a->size * 2]; // (float*) malloc0 (a->size * sizeof (complex));
a->dcbl = CBL::create_cbl (1, a->size, a->in, a->b1, 0, a->rate, 0.02);
a->ibuff = new float[a->size]; // (float*) malloc0 (a->size * sizeof (float));
a->ftovbuff = new float[a->size]; // (float*) malloc0(a->size * sizeof (float));
a->cvtr = FTOV::create_ftov (1, a->size, a->rate, a->ftov_rsize, a->ftov_fmax, a->ibuff, a->ftovbuff);
a->lpbuff = new float[a->size]; // (float*) malloc0 (a->size * sizeof (float));
a->filt = DBQLP::create_dbqlp (1, a->size, a->ftovbuff, a->lpbuff, a->rate, 11.3, 1.0, 1.0, 1);
a->wdbuff = new int[a->size]; // (int*) malloc0 (a->size * sizeof (int));
a->tr_signal = new int[a->size]; // (int*) malloc0 (a->size * sizeof (int));
// window detector
a->wdmult = exp (-1.0 / (a->rate * a->wdtau));
a->wdaverage = 0.0;
// trigger
a->tr_voltage = a->tr_thresh;
a->mute_mult = 1.0 - exp (-1.0 / (a->rate * a->tr_tau_mute));
a->unmute_mult = 1.0 - exp (-1.0 / (a->rate * a->tr_tau_unmute));
// level change
a->ntup = (int)(a->tup * a->rate);
a->ntdown = (int)(a->tdown * a->rate);
a->cup = new float[a->ntup + 1]; // (float*) malloc0 ((a->ntup + 1) * sizeof (float));
a->cdown = new float[a->ntdown + 1]; // (float*) malloc0 ((a->ntdown + 1) * sizeof (float));
compute_ssql_slews (a);
// control
a->state = 0;
a->count = 0;
}
void SSQL::decalc_ssql (SSQL *a)
{
delete[] (a->tr_signal);
delete[] (a->wdbuff);
DBQLP::destroy_dbqlp (a->filt);
delete[] (a->lpbuff);
FTOV::destroy_ftov (a->cvtr);
delete[] (a->ftovbuff);
delete[] (a->ibuff);
CBL::destroy_cbl (a->dcbl);
delete[] (a->b1);
delete[] (a->cdown);
delete[] (a->cup);
}
SSQL* SSQL::create_ssql (
int run,
int size,
float* in,
float* out,
int rate,
double tup,
double tdown,
double muted_gain,
double tau_mute,
double tau_unmute,
double wthresh,
double tr_thresh,
int rsize,
double fmax
)
{
SSQL *a = new SSQL;
a->run = run;
a->size = size;
a->in = in;
a->out = out;
a->rate = rate;
a->tup = tup;
a->tdown = tdown;
a->muted_gain = muted_gain;
a->tr_tau_mute = tau_mute;
a->tr_tau_unmute = tau_unmute;
a->wthresh = wthresh; // PRIMARY SQUELCH THRESHOLD CONTROL
a->tr_thresh = tr_thresh; // value between tr_ss_unmute and tr_ss_mute, default = 0.8197
a->tr_ss_mute = 1.0;
a->tr_ss_unmute = 0.3125;
a->wdtau = 0.5;
a->ftov_rsize = rsize;
a->ftov_fmax = fmax;
calc_ssql (a);
return a;
}
void SSQL::destroy_ssql (SSQL *a)
{
decalc_ssql (a);
delete (a);
}
void SSQL::flush_ssql (SSQL *a)
{
std::fill(a->b1, a->b1 + a->size * 2, 0);
CBL::flush_cbl (a->dcbl);
memset (a->ibuff, 0, a->size * sizeof (float));
memset (a->ftovbuff, 0, a->size * sizeof (float));
FTOV::flush_ftov (a->cvtr);
memset (a->lpbuff, 0, a->size * sizeof (float));
DBQLP::flush_dbqlp (a->filt);
memset (a->wdbuff, 0, a->size * sizeof (int));
memset (a->tr_signal, 0, a->size * sizeof (int));
}
enum _ssqlstate
{
MUTED,
INCREASE,
UNMUTED,
DECREASE
};
void SSQL::xssql (SSQL *a)
{
if (a->run)
{
CBL::xcbl (a->dcbl); // dc block the input signal
for (int i = 0; i < a->size; i++) // extract 'I' component
a->ibuff[i] = a->b1[2 * i];
FTOV::xftov (a->cvtr); // convert frequency to voltage, ignoring amplitude
// WriteAudioWDSP(20.0, a->rate, a->size, a->ftovbuff, 4, 0.99);
DBQLP::xdbqlp (a->filt); // low-pass filter
// WriteAudioWDSP(20.0, a->rate, a->size, a->lpbuff, 4, 0.99);
// calculate the output of the window detector for each sample
for (int i = 0; i < a->size; i++)
{
a->wdaverage = a->wdmult * a->wdaverage + (1.0 - a->wdmult) * a->lpbuff[i];
if ((a->lpbuff[i] - a->wdaverage) > a->wthresh || (a->wdaverage - a->lpbuff[i]) > a->wthresh)
a->wdbuff[i] = 0; // signal unmute
else
a->wdbuff[i] = 1; // signal mute
}
// calculate the trigger signal for each sample
for (int i = 0; i < a->size; i++)
{
if (a->wdbuff[i] == 0)
a->tr_voltage += (a->tr_ss_unmute - a->tr_voltage) * a->unmute_mult;
if (a->wdbuff[i] == 1)
a->tr_voltage += (a->tr_ss_mute - a->tr_voltage) * a->mute_mult;
if (a->tr_voltage > a->tr_thresh) a->tr_signal[i] = 0; // muted
else a->tr_signal[i] = 1; // unmuted
}
// execute state machine; calculate audio output
for (int i = 0; i < a->size; i++)
{
switch (a->state)
{
case MUTED:
if (a->tr_signal[i] == 1)
{
a->state = INCREASE;
a->count = a->ntup;
}
a->out[2 * i + 0] = a->muted_gain * a->in[2 * i + 0];
a->out[2 * i + 1] = a->muted_gain * a->in[2 * i + 1];
break;
case INCREASE:
a->out[2 * i + 0] = a->in[2 * i + 0] * a->cup[a->ntup - a->count];
a->out[2 * i + 1] = a->in[2 * i + 1] * a->cup[a->ntup - a->count];
if (a->count-- == 0)
a->state = UNMUTED;
break;
case UNMUTED:
if (a->tr_signal[i] == 0)
{
a->state = DECREASE;
a->count = a->ntdown;
}
a->out[2 * i + 0] = a->in[2 * i + 0];
a->out[2 * i + 1] = a->in[2 * i + 1];
break;
case DECREASE:
a->out[2 * i + 0] = a->in[2 * i + 0] * a->cdown[a->ntdown - a->count];
a->out[2 * i + 1] = a->in[2 * i + 1] * a->cdown[a->ntdown - a->count];
if (a->count-- == 0)
a->state = MUTED;
break;
}
}
}
else if (a->in != a->out)
std::copy(a->in, a->in + a->size * 2, a->out);
}
void SSQL::setBuffers_ssql (SSQL *a, float* in, float* out)
{
decalc_ssql (a);
a->in = in;
a->out = out;
calc_ssql (a);
}
void SSQL::setSamplerate_ssql (SSQL *a, int rate)
{
decalc_ssql (a);
a->rate = rate;
calc_ssql (a);
}
void SSQL::setSize_ssql (SSQL *a, int size)
{
decalc_ssql (a);
a->size = size;
calc_ssql (a);
}
/********************************************************************************************************
* *
* RXA Properties *
* *
********************************************************************************************************/
void SSQL::SetSSQLRun (RXA& rxa, int run)
{
rxa.ssql->run = run;
}
void SSQL::SetSSQLThreshold (RXA& rxa, double threshold)
{
// 'threshold' should be between 0.0 and 1.0
// WU2O testing: 0.16 is a good default for 'threshold'; => 0.08 for 'wthresh'
rxa.ssql->wthresh = threshold / 2.0;
}
void SSQL::SetSSQLTauMute (RXA& rxa, double tau_mute)
{
// reasonable (wide) range is 0.1 to 2.0
// WU2O testing: 0.1 is good default value
SSQL *a = rxa.ssql;
a->tr_tau_mute = tau_mute;
a->mute_mult = 1.0 - exp (-1.0 / (a->rate * a->tr_tau_mute));
}
void SSQL::SetSSQLTauUnMute (RXA& rxa, double tau_unmute)
{
// reasonable (wide) range is 0.1 to 1.0
// WU2O testing: 0.1 is good default value
SSQL *a = rxa.ssql;
a->tr_tau_unmute = tau_unmute;
a->unmute_mult = 1.0 - exp (-1.0 / (a->rate * a->tr_tau_unmute));
}
} // namespace WDSP