148 lines
3.7 KiB
C
Executable File
148 lines
3.7 KiB
C
Executable File
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/*
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* receiver.c
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*
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* (c) Ruben Undheim 2008
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* (c) Heikki Hannikainen 2008
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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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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*
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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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "config.h"
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#include <string.h>
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#include <time.h>
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#include "receiver.h"
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#include "hmalloc.h"
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#include "filter.h"
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static int sound_levellog=1;
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receiver_on_level_changed on_sound_level_changed=NULL;
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static float coeffs[]={
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2.5959e-55, 2.9479e-49, 1.4741e-43, 3.2462e-38, 3.1480e-33,
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1.3443e-28, 2.5280e-24, 2.0934e-20, 7.6339e-17, 1.2259e-13,
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8.6690e-11, 2.6996e-08, 3.7020e-06, 2.2355e-04, 5.9448e-03,
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6.9616e-02, 3.5899e-01, 8.1522e-01, 8.1522e-01, 3.5899e-01,
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6.9616e-02, 5.9448e-03, 2.2355e-04, 3.7020e-06, 2.6996e-08,
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8.6690e-11, 1.2259e-13, 7.6339e-17, 2.0934e-20, 2.5280e-24,
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1.3443e-28, 3.1480e-33, 3.2462e-38, 1.4741e-43, 2.9479e-49,
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2.5959e-55
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};
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#define COEFFS_L 36
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struct receiver *init_receiver(char name, int num_ch, int ch_ofs)
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{
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struct receiver *rx;
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rx = (struct receiver *) hmalloc(sizeof(struct receiver));
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memset(rx, 0, sizeof(struct receiver));
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rx->filter = filter_init(COEFFS_L, coeffs);
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rx->decoder = hmalloc(sizeof(struct demod_state_t));
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protodec_initialize(rx->decoder, NULL, name);
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rx->name = name;
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rx->lastbit = 0;
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rx->num_ch = num_ch;
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rx->ch_ofs = ch_ofs;
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rx->pll = 0;
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rx->pllinc = 0x10000 / 5;
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rx->prev = 0;
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rx->last_levellog = 0;
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return rx;
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}
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void free_receiver(struct receiver *rx)
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{
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if (rx) {
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filter_free(rx->filter);
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hfree(rx);
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}
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}
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#define INC 16
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#define FILTERED_LEN 8192
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void receiver_run(struct receiver *rx, short *buf, int len)
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{
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float out;
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int curr, bit;
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char b;
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short maxval = 0;
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int level_distance;
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float level;
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int rx_num_ch = rx->num_ch;
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float filtered[FILTERED_LEN];
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int i;
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/* len is number of samples available in buffer for each
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* channels - something like 1024, regardless of number of channels */
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buf += rx->ch_ofs;
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if (len > FILTERED_LEN)
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abort();
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maxval = filter_run_buf(rx->filter, buf, filtered, rx_num_ch, len);
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for (i = 0; i < len; i++) {
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out = filtered[i];
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curr = (out > 0);
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if ((curr ^ rx->prev) == 1) {
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if (rx->pll < (0x10000 / 2)) {
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rx->pll += rx->pllinc / INC;
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} else {
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rx->pll -= rx->pllinc / INC;
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}
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}
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rx->prev = curr;
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rx->pll += rx->pllinc;
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if (rx->pll > 0xffff) {
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/* slice */
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bit = (out > 0);
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/* nrzi decode */
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b = !(bit ^ rx->lastbit);
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/* feed to the decoder */
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protodec_decode(&b, 1, rx->decoder);
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rx->lastbit = bit;
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rx->pll &= 0xffff;
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}
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}
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/* calculate level, and log it */
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level = (float)maxval / (float)32768 * (float)100;
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level_distance = time(NULL) - rx->last_levellog;
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if (level > 95.0 && (level_distance >= 30 || level_distance >= sound_levellog)) {
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if (on_sound_level_changed != NULL) on_sound_level_changed(level, rx->ch_ofs, 1);
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time(&rx->last_levellog);
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} else if (sound_levellog != 0 && level_distance >= sound_levellog) {
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if (on_sound_level_changed != NULL) on_sound_level_changed(level, rx->ch_ofs, 0);
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time(&rx->last_levellog);
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}
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}
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