371 lines
11 KiB
C
371 lines
11 KiB
C
/* ssql.c
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This file is part of a program that implements a Software-Defined Radio.
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Copyright (C) 2023 Warren Pratt, NR0V
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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@pratt.one
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*/
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#include "comm.h"
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/********************************************************************************************************
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* *
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* Frequency to Voltage Converter *
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* *
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********************************************************************************************************/
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FTOV create_ftov (int run, int size, int rate, int rsize, double fmax, double* in, double* out)
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{
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FTOV a = (FTOV) malloc0 (sizeof (ftov));
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a->run = run;
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a->size = size;
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a->rate = rate;
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a->rsize = rsize;
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a->fmax = fmax;
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a->in = in;
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a->out = out;
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a->eps = 0.01;
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a->ring = (int*) malloc0 (a->rsize * sizeof (int));
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a->rptr = 0;
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a->inlast = 0.0;
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a->rcount = 0;
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a->div = a->fmax * 2.0 * a->rsize / a->rate; // fmax * 2 = zero-crossings/sec
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// rsize / rate = sec of data in ring
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// product is # zero-crossings in ring at fmax
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return a;
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}
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void destroy_ftov (FTOV a)
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{
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_aligned_free (a->ring);
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_aligned_free (a);
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}
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void flush_ftov (FTOV a)
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{
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memset (a->ring, 0, a->rsize * sizeof (int));
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a->rptr = 0;
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a->rcount = 0;
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a->inlast = 0.0;
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}
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void xftov (FTOV a)
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{
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// 'ftov' does frequency to voltage conversion looking only at zero crossings of an
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// AC (DC blocked) signal, i.e., ignoring signal amplitude.
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if (a->run)
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{
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if (a->ring[a->rptr] == 1) // if current ring location is a '1' ...
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{
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a->rcount--; // decrement the count
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a->ring[a->rptr] = 0; // set the location to '0'
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}
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if ((a->inlast * a->in[0] < 0.0) && // different signs mean zero-crossing
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(fabs (a->inlast - a->in[0]) > a->eps))
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{
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a->ring[a->rptr] = 1; // set the ring location to '1'
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a->rcount++; // increment the count
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}
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if (++a->rptr == a->rsize) a->rptr = 0; // increment and wrap the pointer as needed
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a->out[0] = min (1.0, (double)a->rcount / a->div); // calculate the output sample
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a->inlast = a->in[a->size - 1]; // save the last input sample for next buffer
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for (int i = 1; i < a->size; i++)
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{
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if (a->ring[a->rptr] == 1) // if current ring location is '1' ...
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{
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a->rcount--; // decrement the count
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a->ring[a->rptr] = 0; // set the location to '0'
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}
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if ((a->in[i - 1] * a->in[i] < 0.0) && // different signs mean zero-crossing
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(fabs (a->in[i - 1] - a->in[i]) > a->eps))
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{
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a->ring[a->rptr] = 1; // set the ring location to '1'
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a->rcount++; // increment the count
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}
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if (++a->rptr == a->rsize) a->rptr = 0; // increment and wrap the pointer as needed
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a->out[i] = min(1.0, (double)a->rcount / a->div); // calculate the output sample
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}
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}
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}
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/*******************************************************************************************************/
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/********************************** END Frequency to Voltage Converter *********************************/
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void compute_ssql_slews(SSQL a)
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{
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int i;
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double delta, theta;
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delta = PI / (double)a->ntup;
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theta = 0.0;
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for (i = 0; i <= a->ntup; i++)
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{
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a->cup[i] = a->muted_gain + (1.0 - a->muted_gain) * 0.5 * (1.0 - cos(theta));
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theta += delta;
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}
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delta = PI / (double)a->ntdown;
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theta = 0.0;
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for (i = 0; i <= a->ntdown; i++)
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{
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a->cdown[i] = a->muted_gain + (1.0 - a->muted_gain) * 0.5 * (1.0 + cos(theta));
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theta += delta;
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}
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}
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void calc_ssql (SSQL a)
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{
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a->b1 = (double*) malloc0 (a->size * sizeof (complex));
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a->dcbl = create_cbl (1, a->size, a->in, a->b1, 0, a->rate, 0.02);
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a->ibuff = (double*) malloc0 (a->size * sizeof (double));
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a->ftovbuff = (double*) malloc0(a->size * sizeof (double));
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a->cvtr = create_ftov (1, a->size, a->rate, a->ftov_rsize, a->ftov_fmax, a->ibuff, a->ftovbuff);
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a->lpbuff = (double*) malloc0 (a->size * sizeof (double));
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a->filt = create_dbqlp (1, a->size, a->ftovbuff, a->lpbuff, a->rate, 11.3, 1.0, 1.0, 1);
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a->wdbuff = (int*) malloc0 (a->size * sizeof (int));
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a->tr_signal = (int*) malloc0 (a->size * sizeof (int));
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// window detector
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a->wdmult = exp (-1.0 / (a->rate * a->wdtau));
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a->wdaverage = 0.0;
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// trigger
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a->tr_voltage = a->tr_thresh;
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a->mute_mult = 1.0 - exp (-1.0 / (a->rate * a->tr_tau_mute));
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a->unmute_mult = 1.0 - exp (-1.0 / (a->rate * a->tr_tau_unmute));
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// level change
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a->ntup = (int)(a->tup * a->rate);
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a->ntdown = (int)(a->tdown * a->rate);
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a->cup = (double*) malloc0 ((a->ntup + 1) * sizeof (double));
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a->cdown = (double*) malloc0 ((a->ntdown + 1) * sizeof (double));
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compute_ssql_slews (a);
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// control
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a->state = 0;
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a->count = 0;
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}
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void decalc_ssql (SSQL a)
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{
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_aligned_free (a->tr_signal);
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_aligned_free (a->wdbuff);
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destroy_dbqlp (a->filt);
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_aligned_free (a->lpbuff);
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destroy_ftov (a->cvtr);
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_aligned_free (a->ftovbuff);
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_aligned_free (a->ibuff);
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destroy_cbl (a->dcbl);
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_aligned_free (a->b1);
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_aligned_free (a->cdown);
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_aligned_free (a->cup);
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}
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SSQL create_ssql (int run, int size, double* in, double* out, int rate, double tup, double tdown,
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double muted_gain, double tau_mute, double tau_unmute, double wthresh, double tr_thresh, int rsize, double fmax)
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{
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SSQL a = (SSQL) malloc0 (sizeof (ssql));
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a->run = run;
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a->size = size;
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a->in = in;
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a->out = out;
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a->rate = rate;
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a->tup = tup;
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a->tdown = tdown;
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a->muted_gain = muted_gain;
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a->tr_tau_mute = tau_mute;
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a->tr_tau_unmute = tau_unmute;
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a->wthresh = wthresh; // PRIMARY SQUELCH THRESHOLD CONTROL
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a->tr_thresh = tr_thresh; // value between tr_ss_unmute and tr_ss_mute, default = 0.8197
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a->tr_ss_mute = 1.0;
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a->tr_ss_unmute = 0.3125;
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a->wdtau = 0.5;
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a->ftov_rsize = rsize;
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a->ftov_fmax = fmax;
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calc_ssql (a);
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return a;
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}
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void destroy_ssql (SSQL a)
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{
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decalc_ssql (a);
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_aligned_free (a);
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}
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void flush_ssql (SSQL a)
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{
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memset (a->b1, 0, a->size * sizeof (complex));
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flush_cbl (a->dcbl);
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memset (a->ibuff, 0, a->size * sizeof (double));
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memset (a->ftovbuff, 0, a->size * sizeof (double));
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flush_ftov (a->cvtr);
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memset (a->lpbuff, 0, a->size * sizeof (double));
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flush_dbqlp (a->filt);
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memset (a->wdbuff, 0, a->size * sizeof (int));
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memset (a->tr_signal, 0, a->size * sizeof (int));
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}
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enum _ssqlstate
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{
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MUTED,
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INCREASE,
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UNMUTED,
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DECREASE
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};
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void xssql (SSQL a)
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{
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if (a->run)
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{
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xcbl (a->dcbl); // dc block the input signal
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for (int i = 0; i < a->size; i++) // extract 'I' component
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a->ibuff[i] = a->b1[2 * i];
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xftov (a->cvtr); // convert frequency to voltage, ignoring amplitude
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// WriteAudioWDSP(20.0, a->rate, a->size, a->ftovbuff, 4, 0.99);
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xdbqlp (a->filt); // low-pass filter
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// WriteAudioWDSP(20.0, a->rate, a->size, a->lpbuff, 4, 0.99);
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// calculate the output of the window detector for each sample
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for (int i = 0; i < a->size; i++)
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{
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a->wdaverage = a->wdmult * a->wdaverage + (1.0 - a->wdmult) * a->lpbuff[i];
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if ((a->lpbuff[i] - a->wdaverage) > a->wthresh || (a->wdaverage - a->lpbuff[i]) > a->wthresh)
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a->wdbuff[i] = 0; // signal unmute
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else
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a->wdbuff[i] = 1; // signal mute
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}
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// calculate the trigger signal for each sample
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for (int i = 0; i < a->size; i++)
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{
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if (a->wdbuff[i] == 0)
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a->tr_voltage += (a->tr_ss_unmute - a->tr_voltage) * a->unmute_mult;
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if (a->wdbuff[i] == 1)
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a->tr_voltage += (a->tr_ss_mute - a->tr_voltage) * a->mute_mult;
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if (a->tr_voltage > a->tr_thresh) a->tr_signal[i] = 0; // muted
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else a->tr_signal[i] = 1; // unmuted
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}
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// execute state machine; calculate audio output
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for (int i = 0; i < a->size; i++)
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{
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switch (a->state)
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{
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case MUTED:
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if (a->tr_signal[i] == 1)
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{
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a->state = INCREASE;
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a->count = a->ntup;
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}
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a->out[2 * i + 0] = a->muted_gain * a->in[2 * i + 0];
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a->out[2 * i + 1] = a->muted_gain * a->in[2 * i + 1];
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break;
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case INCREASE:
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a->out[2 * i + 0] = a->in[2 * i + 0] * a->cup[a->ntup - a->count];
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a->out[2 * i + 1] = a->in[2 * i + 1] * a->cup[a->ntup - a->count];
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if (a->count-- == 0)
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a->state = UNMUTED;
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break;
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case UNMUTED:
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if (a->tr_signal[i] == 0)
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{
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a->state = DECREASE;
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a->count = a->ntdown;
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}
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a->out[2 * i + 0] = a->in[2 * i + 0];
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a->out[2 * i + 1] = a->in[2 * i + 1];
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break;
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case DECREASE:
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a->out[2 * i + 0] = a->in[2 * i + 0] * a->cdown[a->ntdown - a->count];
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a->out[2 * i + 1] = a->in[2 * i + 1] * a->cdown[a->ntdown - a->count];
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if (a->count-- == 0)
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a->state = MUTED;
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break;
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}
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}
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}
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else if (a->in != a->out)
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memcpy (a->out, a->in, a->size * sizeof(complex));
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}
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void setBuffers_ssql (SSQL a, double* in, double* out)
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{
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decalc_ssql (a);
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a->in = in;
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a->out = out;
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calc_ssql (a);
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}
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void setSamplerate_ssql (SSQL a, int rate)
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{
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decalc_ssql (a);
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a->rate = rate;
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calc_ssql (a);
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}
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void setSize_ssql (SSQL a, int size)
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{
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decalc_ssql (a);
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a->size = size;
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calc_ssql (a);
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}
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/********************************************************************************************************
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* *
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* RXA Properties *
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* *
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********************************************************************************************************/
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PORT
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void SetRXASSQLRun (int channel, int run)
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{
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EnterCriticalSection (&ch[channel].csDSP);
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rxa[channel].ssql.p->run = run;
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LeaveCriticalSection (&ch[channel].csDSP);
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}
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PORT
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void SetRXASSQLThreshold (int channel, double threshold)
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{
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// 'threshold' should be between 0.0 and 1.0
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// WU2O testing: 0.16 is a good default for 'threshold'; => 0.08 for 'wthresh'
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EnterCriticalSection (&ch[channel].csDSP);
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rxa[channel].ssql.p->wthresh = threshold / 2.0;
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LeaveCriticalSection (&ch[channel].csDSP);
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}
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PORT
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void SetRXASSQLTauMute (int channel, double tau_mute)
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{
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// reasonable (wide) range is 0.1 to 2.0
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// WU2O testing: 0.1 is good default value
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SSQL a = rxa[channel].ssql.p;
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EnterCriticalSection (&ch[channel].csDSP);
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a->tr_tau_mute = tau_mute;
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a->mute_mult = 1.0 - exp (-1.0 / (a->rate * a->tr_tau_mute));
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LeaveCriticalSection (&ch[channel].csDSP);
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}
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PORT
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void SetRXASSQLTauUnMute (int channel, double tau_unmute)
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{
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// reasonable (wide) range is 0.1 to 1.0
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// WU2O testing: 0.1 is good default value
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SSQL a = rxa[channel].ssql.p;
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EnterCriticalSection (&ch[channel].csDSP);
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a->tr_tau_unmute = tau_unmute;
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a->unmute_mult = 1.0 - exp (-1.0 / (a->rate * a->tr_tau_unmute));
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LeaveCriticalSection (&ch[channel].csDSP);
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}
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