An implementation of Analog cellular networks like A-Netz, B-Netz, C-Netz, NMT, AMPS, TACS, JTACS, Radiocom 2000, IMTS, MPT1327, Eurosignal and more http://osmocom-analog.eversberg.eu/
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osmocom-analog/src/jolly/dsp.c

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12 KiB

/* digital signal processing for jollycom
*
* (C) 2017 by Andreas Eversberg <jolly@eversberg.eu>
* All Rights Reserved
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
#define CHAN jolly->sender.kanal
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <math.h>
#include "../libsample/sample.h"
#include "../libtimer/timer.h"
#include "../libdebug/debug.h"
#include "../libmobile/call.h"
#include "jolly.h"
#include "dsp.h"
#include "voice.h"
#define db2level(db) pow(10, (double)db / 20.0)
/* transceiver parameters */
#define MAX_DEVIATION 5000.0 /* deviation of signal */
#define MAX_MODULATION 4000.0 /* frequency spectrum of signal */
#define DBM0_DEVIATION 3000.0 /* deviation of dBm0 at 1 kHz (generally used with 25 kHz channel spacing) */
#define MAX_DISPLAY 1.0 /* maximum level to display */
#define TX_INFO_TONE 1.0 /* Level of tone relative to dBm0 (each component) */
#define TX_ACK_TONE 0.1 /* Level of tone relative to dBm0 */
#define INFO_TONE_F1 640.0
#define INFO_TONE_F2 670.0
#define ACK_TONE 1000.0
/* Squelch */
#define MUTE_TIME 0.1 /* Time until muting */
#define DELAY_TIME 0.15 /* delay, so we don't hear the noise before squelch mutes */
#define ACK_TIME 0.15 /* Time to play the ack tone */
#define REPEATER_TIME 5.0 /* Time to transmit in repeater mode */
/* table for fast sine generation */
static sample_t dsp_info_tone[65536];
static sample_t dsp_ack_tone[65536];
/* global init for audio processing */
void dsp_init(void)
{
int i;
double s;
PDEBUG(DDSP, DEBUG_DEBUG, "Generating sine tables.\n");
for (i = 0; i < 65536; i++) {
s = sin((double)i / 65536.0 * 2.0 * M_PI);
dsp_info_tone[i] = s * TX_INFO_TONE;
dsp_ack_tone[i] = s * TX_ACK_TONE;
}
}
/* Init transceiver instance. */
int dsp_init_sender(jolly_t *jolly, int nbfm, double squelch_db, int repeater)
{
int rc;
/* init squelch */
squelch_init(&jolly->squelch, jolly->sender.kanal, squelch_db, MUTE_TIME, MUTE_TIME);
if (!isinf(squelch_db))
jolly->is_mute = 1;
/* set modulation parameters (NBFM uses half channel spacing, so we use half deviation) */
if (nbfm)
sender_set_fm(&jolly->sender, MAX_DEVIATION / 2.0, MAX_MODULATION, DBM0_DEVIATION / 2.0, MAX_DISPLAY);
else
sender_set_fm(&jolly->sender, MAX_DEVIATION, MAX_MODULATION, DBM0_DEVIATION, MAX_DISPLAY);
/* init dtmf audio processing.
* each frequency may be +6 dB deviation, which means a total deviation of +12 dB is allowed for detection.
* also we allow a minimum of -30 dB for each tone. */
rc = dtmf_decode_init(&jolly->dtmf, jolly, jolly_receive_dtmf, 8000, db2level(6.0), db2level(-30.0));
if (rc < 0) {
PDEBUG(DDSP, DEBUG_ERROR, "Failed to init DTMF decoder!\n");
goto error;
}
/* tones */
jolly->dt_phaseshift65536[0] = 65536.0 / ((double)jolly->sender.samplerate / INFO_TONE_F1);
jolly->dt_phaseshift65536[1] = 65536.0 / ((double)jolly->sender.samplerate / INFO_TONE_F2);
jolly->ack_phaseshift65536 = 65536.0 / ((double)jolly->sender.samplerate / ACK_TONE);
PDEBUG(DDSP, DEBUG_DEBUG, "TX %.0f Hz phaseshift = %.4f\n", INFO_TONE_F1, jolly->dt_phaseshift65536[0]);
PDEBUG(DDSP, DEBUG_DEBUG, "TX %.0f Hz phaseshift = %.4f\n", INFO_TONE_F2, jolly->dt_phaseshift65536[1]);
PDEBUG(DDSP, DEBUG_DEBUG, "TX %.0f Hz phaseshift = %.4f\n", ACK_TONE, jolly->ack_phaseshift65536);
jolly->ack_max = (int)((double)jolly->sender.samplerate * ACK_TIME);
/* delay buffer */
jolly->delay_max = (int)((double)jolly->sender.samplerate * DELAY_TIME);
jolly->delay_spl = calloc(jolly->delay_max, sizeof(*jolly->delay_spl));
if (!jolly->delay_spl) {
PDEBUG(DDSP, DEBUG_ERROR, "No mem for delay buffer!\n");
goto error;
}
/* repeater */
jolly->repeater = repeater;
jolly->repeater_max = (int)((double)jolly->sender.samplerate * REPEATER_TIME);
rc = jitter_create(&jolly->repeater_dejitter, jolly->sender.samplerate / 5);
if (rc < 0) {
PDEBUG(DDSP, DEBUG_ERROR, "Failed to create and init repeater buffer!\n");
goto error;
}
jolly->dmp_dtmf_low = display_measurements_add(&jolly->sender.dispmeas, "DTMF Low", "%.1f dB (last)", DISPLAY_MEAS_LAST, DISPLAY_MEAS_LEFT, -30.0, 6.0, 0.0);
jolly->dmp_dtmf_high = display_measurements_add(&jolly->sender.dispmeas, "DTMF High", "%.1f dB (last)", DISPLAY_MEAS_LAST, DISPLAY_MEAS_LEFT, -30.0, 6.0, 0.0);
return 0;
error:
dsp_cleanup_sender(jolly);
return -EINVAL;
}
void dsp_cleanup_sender(jolly_t *jolly)
{
jitter_destroy(&jolly->repeater_dejitter);
dtmf_decode_exit(&jolly->dtmf);
if (jolly->delay_spl) {
free(jolly->delay_spl);
jolly->delay_spl = NULL;
}
}
void set_speech_string(jolly_t *jolly, char announcement, const char *number)
{
jolly->speech_string[0] = announcement;
jolly->speech_string[1] = '\0';
strncat(jolly->speech_string, number, sizeof(jolly->speech_string) - 1);
jolly->speech_digit = 0;
jolly->speech_pos = 0;
}
void reset_speech_string(jolly_t *jolly)
{
jolly->speech_string[0] = '\0';
jolly->speech_digit = 0;
}
/* Generate audio stream from voice samples. */
static int speak_voice(jolly_t *jolly, sample_t *samples, int length)
{
sample_t *spl;
int size;
int i;
int count = 0;
again:
/* no speech */
if (!jolly->speech_string[jolly->speech_digit])
return count;
/* select sample */
switch (jolly->speech_string[jolly->speech_digit]) {
case 'i':
spl = jolly_voice.spl[10];
size = jolly_voice.size[10];
if (!jolly->speech_pos)
PDEBUG(DDSP, DEBUG_DEBUG, "speaking 'incoming'.\n");
break;
case 'o':
spl = jolly_voice.spl[11];
size = jolly_voice.size[11];
if (!jolly->speech_pos)
PDEBUG(DDSP, DEBUG_DEBUG, "speaking 'outgoing'.\n");
break;
case 'r':
spl = jolly_voice.spl[12];
size = jolly_voice.size[12];
if (!jolly->speech_pos)
PDEBUG(DDSP, DEBUG_DEBUG, "speaking 'released'.\n");
break;
case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
spl = jolly_voice.spl[jolly->speech_string[jolly->speech_digit] - '0'];
size = jolly_voice.size[jolly->speech_string[jolly->speech_digit] - '0'];
if (!jolly->speech_pos)
PDEBUG(DDSP, DEBUG_DEBUG, "speaking digit '%c'.\n", jolly->speech_string[jolly->speech_digit]);
break;
default:
jolly->speech_digit++;
goto again;
}
/* copy sample */
for (; length && jolly->speech_pos < size; i++) {
*samples++ = spl[jolly->speech_pos++];
length--;
count++;
}
if (jolly->speech_pos == size) {
jolly->speech_pos = 0;
jolly->speech_digit++;
if (!jolly->speech_string[jolly->speech_digit])
speech_finished(jolly);
goto again;
}
return count;
}
static void delay_audio(jolly_t *jolly, sample_t *samples, int count)
{
sample_t *spl, s;
int pos, max;
int i;
spl = jolly->delay_spl;
pos = jolly->delay_pos;
max = jolly->delay_max;
/* feed audio though delay buffer */
for (i = 0; i < count; i++) {
s = samples[i];
samples[i] = spl[pos];
spl[pos] = s;
if (++pos == max)
pos = 0;
}
jolly->delay_pos = pos;
}
/* Generate audio stream from tone. Keep phase for next call of function. */
static void dial_tone(jolly_t *jolly, sample_t *samples, int length)
{
double *phaseshift, *phase;
int i;
phaseshift = jolly->dt_phaseshift65536;
phase = jolly->dt_phase65536;
for (i = 0; i < length; i++) {
*samples = dsp_info_tone[(uint16_t)(phase[0])];
*samples++ += dsp_info_tone[(uint16_t)(phase[1])];
phase[0] += phaseshift[0];
if (phase[0] >= 65536)
phase[0] -= 65536;
phase[1] += phaseshift[1];
if (phase[1] >= 65536)
phase[1] -= 65536;
}
}
static void ack_tone(jolly_t *jolly, sample_t *samples, int length)
{
double phaseshift, phase;
int i;
phaseshift = jolly->ack_phaseshift65536;
phase = jolly->ack_phase65536;
for (i = 0; i < length; i++) {
*samples++ = dsp_ack_tone[(uint16_t)phase];
phase += phaseshift;
if (phase >= 65536)
phase -= 65536;
}
jolly->ack_phase65536 = phase;
}
/* Process received audio stream from radio unit. */
void sender_receive(sender_t *sender, sample_t *samples, int length, double rf_level_db)
{
jolly_t *jolly = (jolly_t *) sender;
sample_t *spl;
int count;
int pos;
int i;
/* process signal mute/loss, also for DTMF tones */
switch (squelch(&jolly->squelch, rf_level_db, (double)length / (double)jolly->sender.samplerate)) {
case SQUELCH_LOSS:
case SQUELCH_MUTE:
if (!jolly->is_mute) {
PDEBUG_CHAN(DDSP, DEBUG_INFO, "Low RF level, muting.\n");
jolly->ack_count = jolly->ack_max;
jolly->repeater_count = jolly->repeater_max;
}
jolly->is_mute = 1;
memset(samples, 0, sizeof(*samples) * length);
break;
default:
if (jolly->is_mute)
PDEBUG_CHAN(DDSP, DEBUG_INFO, "High RF level, unmuting; turning transmitter on.\n");
jolly->is_mute = 0;
break;
}
/* delay audio to prevent noise before squelch mutes */
delay_audio(jolly, samples, length);
/* play ack tone */
if (jolly->ack_count) {
ack_tone(jolly, samples, length);
jolly->ack_count -= length;
if (jolly->ack_count < 0)
jolly->ack_count = 0;
}
/* if repeater mode, store sample in jitter buffer */
if (jolly->repeater)
jitter_save(&jolly->repeater_dejitter, samples, length);
/* downsample, decode DTMF */
count = samplerate_downsample(&jolly->sender.srstate, samples, length);
dtmf_decode(&jolly->dtmf, samples, count);
/* Forward audio to network (call process) and feed DTMF decoder. */
if (jolly->callref) {
spl = jolly->sender.rxbuf;
pos = jolly->sender.rxbuf_pos;
for (i = 0; i < count; i++) {
spl[pos++] = samples[i];
if (pos == 160) {
call_up_audio(jolly->callref, spl, 160);
pos = 0;
}
}
jolly->sender.rxbuf_pos = pos;
} else
jolly->sender.rxbuf_pos = 0;
}
/* Provide stream of audio toward radio unit */
void sender_send(sender_t *sender, sample_t *samples, uint8_t *power, int length)
{
jolly_t *jolly = (jolly_t *) sender;
int count;
switch (jolly->state) {
case STATE_IDLE:
if (jolly->repeater && (!jolly->is_mute || jolly->ack_count || jolly->repeater_count)) {
memset(power, 1, length);
if (jolly->repeater_count) {
jolly->repeater_count -= length;
if (jolly->repeater_count < 0) {
PDEBUG_CHAN(DDSP, DEBUG_INFO, "turning transmitter off.\n");
jolly->repeater_count = 0;
}
}
} else {
/* pwr off */
memset(power, 0, length);
}
memset(samples, 0, length * sizeof(*samples));
break;
case STATE_CALL:
case STATE_CALL_DIALING:
memset(power, 1, length);
jitter_load(&jolly->sender.dejitter, samples, length);
break;
case STATE_OUT_VERIFY:
case STATE_IN_PAGING:
case STATE_RELEASED:
memset(power, 1, length);
count = speak_voice(jolly, samples, length);
if (count) {
/* if voice ends, fill silence */
if (count < length)
memset(samples + count, 0, sizeof(*samples) * (length - count));
break;
}
/* in case of no voice: */
/* FALLTHRU */
default:
memset(power, 1, length);
dial_tone(jolly, samples, length);
}
/* if repeater mode, sum samples from jitter buffer to samples */
if (jolly->repeater) {
sample_t uplink[length];
int i;
jitter_load(&jolly->repeater_dejitter, uplink, length);
for (i = 0; i < length; i++)
samples[i] += uplink[i];
}
}