295 lines
7.1 KiB
C
295 lines
7.1 KiB
C
/* amd.c
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This file is part of a program that implements a Software-Defined Radio.
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Copyright (C) 2012, 2013 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@wpratt.com
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*/
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#include "comm.h"
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AMD create_amd
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(
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int run,
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int buff_size,
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double *in_buff,
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double *out_buff,
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int mode,
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int levelfade,
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int sbmode,
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int sample_rate,
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double fmin,
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double fmax,
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double zeta,
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double omegaN,
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double tauR,
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double tauI
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)
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{
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AMD a = (AMD) malloc0 (sizeof(amd));
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a->run = run;
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a->buff_size = buff_size;
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a->in_buff = in_buff;
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a->out_buff = out_buff;
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a->mode = mode;
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a->levelfade = levelfade;
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a->sbmode = sbmode;
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a->sample_rate = (double)sample_rate;
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a->fmin = fmin;
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a->fmax = fmax;
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a->zeta = zeta;
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a->omegaN = omegaN;
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a->tauR = tauR;
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a->tauI = tauI;
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init_amd(a);
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return a;
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}
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void destroy_amd(AMD a)
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{
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_aligned_free (a);
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}
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void init_amd(AMD a)
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{
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//pll
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a->omega_min = TWOPI * a->fmin / a->sample_rate;
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a->omega_max = TWOPI * a->fmax / a->sample_rate;
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a->g1 = 1.0 - exp(-2.0 * a->omegaN * a->zeta / a->sample_rate);
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a->g2 = -a->g1 + 2.0 * (1 - exp(-a->omegaN * a->zeta / a->sample_rate) * cos(a->omegaN / a->sample_rate * sqrt(1.0 - a->zeta * a->zeta)));
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a->phs = 0.0;
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a->fil_out = 0.0;
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a->omega = 0.0;
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//fade leveler
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a->dc = 0.0;
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a->dc_insert = 0.0;
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a->mtauR = exp(-1.0 / (a->sample_rate * a->tauR));
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a->onem_mtauR = 1.0 - a->mtauR;
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a->mtauI = exp(-1.0 / (a->sample_rate * a->tauI));
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a->onem_mtauI = 1.0 - a->mtauI;
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//sideband separation
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a->c0[0] = -0.328201924180698;
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a->c0[1] = -0.744171491539427;
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a->c0[2] = -0.923022915444215;
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a->c0[3] = -0.978490468768238;
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a->c0[4] = -0.994128272402075;
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a->c0[5] = -0.998458978159551;
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a->c0[6] = -0.999790306259206;
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a->c1[0] = -0.0991227952747244;
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a->c1[1] = -0.565619728761389;
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a->c1[2] = -0.857467122550052;
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a->c1[3] = -0.959123933111275;
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a->c1[4] = -0.988739372718090;
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a->c1[5] = -0.996959189310611;
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a->c1[6] = -0.999282492800792;
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}
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void flush_amd (AMD a)
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{
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a->dc = 0.0;
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a->dc_insert = 0.0;
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}
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void xamd (AMD a)
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{
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int i;
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double audio;
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double vco[2];
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double corr[2];
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double det;
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double del_out;
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double ai, bi, aq, bq;
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double ai_ps, bi_ps, aq_ps, bq_ps;
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int j, k;
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if (a->run)
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{
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switch (a->mode)
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{
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case 0: //AM Demodulator
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{
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for (i = 0; i < a->buff_size; i++)
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{
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audio = sqrt(a->in_buff[2 * i + 0] * a->in_buff[2 * i + 0] + a->in_buff[2 * i + 1] * a->in_buff[2 * i + 1]);
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if (a->levelfade)
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{
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a->dc = a->mtauR * a->dc + a->onem_mtauR * audio;
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a->dc_insert = a->mtauI * a->dc_insert + a->onem_mtauI * audio;
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audio += a->dc_insert - a->dc;
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}
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a->out_buff[2 * i + 0] = audio;
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a->out_buff[2 * i + 1] = audio;
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}
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break;
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}
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case 1: //Synchronous AM Demodulator with Sideband Separation
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{
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for (i = 0; i < a->buff_size; i++)
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{
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vco[0] = cos(a->phs);
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vco[1] = sin(a->phs);
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ai = a->in_buff[2 * i + 0] * vco[0];
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bi = a->in_buff[2 * i + 0] * vco[1];
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aq = a->in_buff[2 * i + 1] * vco[0];
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bq = a->in_buff[2 * i + 1] * vco[1];
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if (a->sbmode != 0)
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{
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a->a[0] = a->dsI;
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a->b[0] = bi;
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a->c[0] = a->dsQ;
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a->d[0] = aq;
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a->dsI = ai;
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a->dsQ = bq;
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for (j = 0; j < STAGES; j++)
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{
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k = 3 * j;
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a->a[k + 3] = a->c0[j] * (a->a[k] - a->a[k + 5]) + a->a[k + 2];
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a->b[k + 3] = a->c1[j] * (a->b[k] - a->b[k + 5]) + a->b[k + 2];
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a->c[k + 3] = a->c0[j] * (a->c[k] - a->c[k + 5]) + a->c[k + 2];
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a->d[k + 3] = a->c1[j] * (a->d[k] - a->d[k + 5]) + a->d[k + 2];
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}
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ai_ps = a->a[OUT_IDX];
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bi_ps = a->b[OUT_IDX];
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bq_ps = a->c[OUT_IDX];
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aq_ps = a->d[OUT_IDX];
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for (j = OUT_IDX + 2; j > 0; j--)
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{
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a->a[j] = a->a[j - 1];
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a->b[j] = a->b[j - 1];
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a->c[j] = a->c[j - 1];
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a->d[j] = a->d[j - 1];
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}
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}
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corr[0] = +ai + bq;
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corr[1] = -bi + aq;
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switch(a->sbmode)
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{
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case 0: //both sidebands
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{
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audio = corr[0];
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break;
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}
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case 1: //LSB
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{
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audio = (ai_ps - bi_ps) + (aq_ps + bq_ps);
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break;
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}
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case 2: //USB
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{
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audio = (ai_ps + bi_ps) - (aq_ps - bq_ps);
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break;
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}
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}
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if (a->levelfade)
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{
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a->dc = a->mtauR * a->dc + a->onem_mtauR * audio;
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a->dc_insert = a->mtauI * a->dc_insert + a->onem_mtauI * corr[0];
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audio += a->dc_insert - a->dc;
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}
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a->out_buff[2 * i + 0] = audio;
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a->out_buff[2 * i + 1] = audio;
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if ((corr[0] == 0.0) && (corr[1] == 0.0)) corr[0] = 1.0;
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det = atan2(corr[1], corr[0]);
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del_out = a->fil_out;
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a->omega += a->g2 * det;
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if (a->omega < a->omega_min) a->omega = a->omega_min;
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if (a->omega > a->omega_max) a->omega = a->omega_max;
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a->fil_out = a->g1 * det + a->omega;
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a->phs += del_out;
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while (a->phs >= TWOPI) a->phs -= TWOPI;
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while (a->phs < 0.0) a->phs += TWOPI;
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}
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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_buff != a->out_buff)
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memcpy (a->out_buff, a->in_buff, a->buff_size * sizeof(complex));
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}
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void setBuffers_amd (AMD a, double* in, double* out)
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{
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a->in_buff = in;
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a->out_buff = out;
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}
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void setSamplerate_amd (AMD a, int rate)
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{
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a->sample_rate = rate;
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init_amd(a);
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}
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void setSize_amd (AMD a, int size)
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{
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a->buff_size = size;
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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 void
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SetRXAAMDRun(int channel, int run)
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{
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AMD a = rxa[channel].amd.p;
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if (a->run != run)
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{
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RXAbp1Check (channel, run, rxa[channel].snba.p->run, rxa[channel].emnr.p->run,
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rxa[channel].anf.p->run, rxa[channel].anr.p->run,
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rxa[channel].rnnr.p->run, rxa[channel].sbnr.p->run); // NR3 + NR4 support
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EnterCriticalSection (&ch[channel].csDSP);
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a->run = run;
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RXAbp1Set (channel);
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LeaveCriticalSection (&ch[channel].csDSP);
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}
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}
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PORT void
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SetRXAAMDSBMode(int channel, int sbmode)
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{
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EnterCriticalSection (&ch[channel].csDSP);
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rxa[channel].amd.p->sbmode = sbmode;
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LeaveCriticalSection (&ch[channel].csDSP);
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}
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PORT void
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SetRXAAMDFadeLevel(int channel, int levelfade)
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{
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EnterCriticalSection (&ch[channel].csDSP);
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rxa[channel].amd.p->levelfade = levelfade;
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LeaveCriticalSection (&ch[channel].csDSP);
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}
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