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-rw-r--r--src/fl2k_fm.c621
1 files changed, 0 insertions, 621 deletions
diff --git a/src/fl2k_fm.c b/src/fl2k_fm.c
deleted file mode 100644
index b22efcd..0000000
--- a/src/fl2k_fm.c
+++ /dev/null
@@ -1,621 +0,0 @@
-/*
- * osmo-fl2k, turns FL2000-based USB 3.0 to VGA adapters into
- * low cost DACs
- *
- * Copyright (C) 2016-2018 by Steve Markgraf <steve@steve-m.de>
- *
- * based on FM modulator code from VGASIG:
- * Copyright (C) 2009 by Bartek Kania <mbk@gnarf.org>
- *
- * SPDX-License-Identifier: GPL-2.0+
- *
- * 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, see <http://www.gnu.org/licenses/>.
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <signal.h>
-#include <string.h>
-#include <errno.h>
-
-#ifndef _WIN32
-#include <unistd.h>
-#include <fcntl.h>
-#include <getopt.h>
-#else
-#include <windows.h>
-#include <io.h>
-#include <fcntl.h>
-#include "getopt/getopt.h"
-#endif
-
-#include <math.h>
-#include <pthread.h>
-
-#include "osmo-fl2k.h"
-#include "rds_mod.h"
-
-#define BUFFER_SAMPLES_SHIFT 16
-#define BUFFER_SAMPLES (1 << BUFFER_SAMPLES_SHIFT)
-#define BUFFER_SAMPLES_MASK ((1 << BUFFER_SAMPLES_SHIFT)-1)
-
-#define AUDIO_BUF_SIZE 1024
-
-fl2k_dev_t *dev = NULL;
-int do_exit = 0;
-
-pthread_t fm_thread;
-pthread_mutex_t cb_mutex;
-pthread_mutex_t fm_mutex;
-pthread_cond_t cb_cond;
-pthread_cond_t fm_cond;
-
-FILE *file;
-int8_t *txbuf = NULL;
-int8_t *fmbuf = NULL;
-int8_t *buf1 = NULL;
-int8_t *buf2 = NULL;
-
-uint32_t samp_rate = 100000000;
-
-/* default signal parameters */
-#define PILOT_FREQ 19000 /* In Hz */
-#define STEREO_CARRIER 38000 /* In Hz */
-
-int deviation = 75000;
-int carrier_freq = 97000000;
-int carrier_per_signal;
-int input_freq = 44100;
-int stereo_flag = 0;
-int rds_flag = 0;
-
-double *freqbuf;
-double *slopebuf;
-int writepos, readpos;
-
-void usage(void)
-{
- fprintf(stderr,
- "fl2k_fm, an FM modulator for FL2K VGA dongles\n\n"
- "Usage:"
- "\t[-d device index (default: 0)]\n"
- "\t[-c carrier frequency (default: 9.7 MHz)]\n"
- "\t[-f FM deviation (default: 75000 Hz, WBFM)]\n"
- "\t[-i input audio sample rate (default: 44100 Hz for mono FM)]\n"
- "\t[-s samplerate in Hz (default: 100 MS/s)]\n"
- "\t[--rds (enables RDS, forces audio sample rate to 228 kHz)]\n"
- "\t[--stereo (enables stereo, requires audio sample rate >= 114 kHz)]\n"
- "\tfilename (use '-' to read from stdin)\n\n"
- );
- exit(1);
-}
-
-#ifdef _WIN32
-BOOL WINAPI
-sighandler(int signum)
-{
- if (CTRL_C_EVENT == signum) {
- fprintf(stderr, "Signal caught, exiting!\n");
- fl2k_stop_tx(dev);
- do_exit = 1;
- pthread_cond_signal(&fm_cond);
- return TRUE;
- }
- return FALSE;
-}
-#else
-static void sighandler(int signum)
-{
- fprintf(stderr, "Signal caught, exiting!\n");
- fl2k_stop_tx(dev);
- do_exit = 1;
- pthread_cond_signal(&fm_cond);
-}
-#endif
-
-/* DDS Functions */
-
-#ifndef M_PI
-# define M_PI 3.14159265358979323846 /* pi */
-# define M_PI_2 1.57079632679489661923 /* pi/2 */
-# define M_PI_4 0.78539816339744830962 /* pi/4 */
-# define M_1_PI 0.31830988618379067154 /* 1/pi */
-# define M_2_PI 0.63661977236758134308 /* 2/pi */
-#endif
-#define DDS_2PI (M_PI * 2) /* 2 * Pi */
-#define DDS_3PI2 (M_PI_2 * 3) /* 3/2 * pi */
-
-#define SIN_TABLE_ORDER 8
-#define SIN_TABLE_SHIFT (32 - SIN_TABLE_ORDER)
-#define SIN_TABLE_LEN (1 << SIN_TABLE_ORDER)
-#define ANG_INCR (0xffffffff / DDS_2PI)
-
-int8_t sine_table[SIN_TABLE_LEN];
-int sine_table_init = 0;
-
-typedef struct {
- double sample_freq;
- double freq;
- double fslope;
- unsigned long int phase;
- unsigned long int phase_step;
- unsigned long int phase_slope;
-} dds_t;
-
-static inline void dds_setphase(dds_t *dds, double phase)
-{
- dds->phase = phase * ANG_INCR;
-}
-
-static inline double dds_getphase(dds_t *dds)
-{
- return dds->phase / ANG_INCR;
-}
-
-static inline void dds_set_freq(dds_t *dds, double freq, double fslope)
-{
- dds->fslope = fslope;
- dds->phase_step = (freq / dds->sample_freq) * 2 * M_PI * ANG_INCR;
-
- /* The slope parameter is used with the FM modulator to create
- * a simple but very fast and effective interpolation filter.
- * See the fm modulator for details */
- dds->freq = freq;
- dds->phase_slope = (fslope / dds->sample_freq) * 2 * M_PI * ANG_INCR;
-}
-
-dds_t dds_init(double sample_freq, double freq, double phase)
-{
- dds_t dds;
- int i;
-
- dds.sample_freq = sample_freq;
- dds.phase = phase * ANG_INCR;
- dds_set_freq(&dds, freq, 0);
-
- /* Initialize sine table, prescaled for 8 bit signed integer */
- if (!sine_table_init) {
- double incr = 1.0 / (double)SIN_TABLE_LEN;
- for (i = 0; i < SIN_TABLE_LEN; i++)
- sine_table[i] = sin(incr * i * DDS_2PI) * 127;
-
- sine_table_init = 1;
- }
-
- return dds;
-}
-
-static inline int8_t dds_real(dds_t *dds)
-{
- int tmp;
-
- tmp = dds->phase >> SIN_TABLE_SHIFT;
- dds->phase += dds->phase_step;
- dds->phase &= 0xffffffff;
-
- dds->phase_step += dds->phase_slope;
-
- return sine_table[tmp];
-}
-
-static inline void dds_real_buf(dds_t *dds, int8_t *buf, int count)
-{
- int i;
- for (i = 0; i < count; i++)
- buf[i] = dds_real(dds);
-}
-
-/* Signal generation and some helpers */
-
-/* Generate the radio signal using the pre-calculated frequency information
- * in the freq buffer */
-static void *fm_worker(void *arg)
-{
- register double freq;
- register double tmp;
- dds_t carrier;
- int8_t *tmp_ptr;
- uint32_t len = 0;
- uint32_t readlen, remaining;
- int buf_prefilled = 0;
-
- /* Prepare the oscillators */
- carrier = dds_init(samp_rate, carrier_freq, 0);
-
- while (!do_exit) {
- dds_set_freq(&carrier, freqbuf[readpos], slopebuf[readpos]);
- readpos++;
- readpos &= BUFFER_SAMPLES_MASK;
-
- /* check if we reach the end of the buffer */
- if ((len + carrier_per_signal) > FL2K_BUF_LEN) {
- readlen = FL2K_BUF_LEN - len;
- remaining = carrier_per_signal - readlen;
- dds_real_buf(&carrier, &fmbuf[len], readlen);
-
- if (buf_prefilled) {
- /* swap buffers */
- tmp_ptr = fmbuf;
- fmbuf = txbuf;
- txbuf = tmp_ptr;
- pthread_cond_wait(&cb_cond, &cb_mutex);
- }
-
- dds_real_buf(&carrier, fmbuf, remaining);
- len = remaining;
-
- buf_prefilled = 1;
- } else {
- dds_real_buf(&carrier, &fmbuf[len], carrier_per_signal);
- len += carrier_per_signal;
- }
-
- pthread_cond_signal(&fm_cond);
- }
-
- pthread_exit(NULL);
-}
-
-static inline int writelen(int maxlen)
-{
- int rp = readpos;
- int len;
- int r;
-
- if (rp < writepos)
- rp += BUFFER_SAMPLES;
-
- len = rp - writepos;
-
- r = len > maxlen ? maxlen : len;
-
- return r;
-}
-
-static inline double modulate_sample(int lastwritepos, double lastfreq, double sample)
-{
- double freq, slope;
-
- /* Calculate modulator frequency at this point to lessen
- * the calculations needed in the signal generator */
- freq = sample * deviation;
- freq += carrier_freq;
-
- /* What we do here is calculate a linear "slope" from
- the previous sample to this one. This is then used by
- the modulator to gently increase/decrease the frequency
- with each sample without the need to recalculate
- the dds parameters. In fact this gives us a very
- efficient and pretty good interpolation filter. */
- slope = freq - lastfreq;
- slope /= carrier_per_signal;
- slopebuf[lastwritepos] = slope;
- freqbuf[writepos] = freq;
-
- return freq;
-}
-
-void fm_modulator_mono(int use_rds)
-{
- unsigned int i;
- size_t len;
- double freq;
- double lastfreq = carrier_freq;
- int16_t audio_buf[AUDIO_BUF_SIZE];
- uint32_t lastwritepos = writepos;
- double sample;
- double rds_samples[AUDIO_BUF_SIZE];
-
- while (!do_exit) {
- len = writelen(AUDIO_BUF_SIZE);
- if (len > 1) {
- len = fread(audio_buf, 2, len, file);
-
- if (len == 0)
- do_exit = 1;
-
- if (use_rds)
- get_rds_samples(rds_samples, len);
-
- for (i = 0; i < len; i++) {
- sample = audio_buf[i] / 32767.0;
-
- if (use_rds) {
- sample *= 4;
- sample += rds_samples[i];
- sample /= 5;
- }
-
- /* Modulate and buffer the sample */
- lastfreq = modulate_sample(lastwritepos, lastfreq, sample);
- lastwritepos = writepos++;
- writepos %= BUFFER_SAMPLES;
- }
- } else {
- pthread_cond_wait(&fm_cond, &fm_mutex);
- }
- }
-}
-
-void fm_modulator_stereo(int use_rds)
-{
- unsigned int i;
- size_t len, sample_cnt;
- double freq;
- double lastfreq = carrier_freq;
- int16_t audio_buf[AUDIO_BUF_SIZE];
- uint32_t lastwritepos = writepos;
-
- dds_t pilot, stereo;
- double L, R, LpR, LmR, sample;
- double rds_samples[AUDIO_BUF_SIZE];
-
- /* Prepare stereo carriers */
- pilot = dds_init(input_freq, PILOT_FREQ, 0);
- stereo = dds_init(input_freq, STEREO_CARRIER, 0);
-
- while (!do_exit) {
- len = writelen(AUDIO_BUF_SIZE);
- if (len > 1 && !(len % 2)) {
- len = fread(audio_buf, 2, len, file);
-
- if (len == 0)
- do_exit = 1;
-
- /* stereo => two audio samples per baseband sample */
- sample_cnt = len/2;
-
- if (use_rds)
- get_rds_samples(rds_samples, sample_cnt);
-
- for (i = 0; i < sample_cnt; i++) {
- /* Get samples for both channels, and calculate the
- * mono (L+R) and the difference signal used to recreate
- * the stereo data (L-R). */
- L = audio_buf[i*2] / 32767.0;
- R = audio_buf[i*2+1] / 32767.0;
- LpR = (L + R) / 2;
- LmR = (L - R) / 2;
-
- /* Create a composite sample consisting of the mono
- * signal at baseband, a 19kHz pilot and a the difference
- * signal DSB-SC modulated on a 38kHz carrier */
- sample = 4.05 * LpR; /* Mono signal */
- sample += 0.9 * (dds_real(&pilot)/127.0); /* Pilot */
- sample += 4.05 * LmR * (dds_real(&stereo)/127.0); /* DSB-SC stereo */
-
- if (use_rds) {
- /* add RDS signal */
- sample += rds_samples[i];
-
- /* Normalize so we get the signal within [-1, 1] */
- sample /= 10;
- } else {
- sample /= 9;
- }
-
- lastfreq = modulate_sample(lastwritepos, lastfreq, sample);
-
- lastwritepos = writepos++;
- writepos %= BUFFER_SAMPLES;
- }
- } else {
- pthread_cond_wait(&fm_cond, &fm_mutex);
- }
- }
-}
-
-void fl2k_callback(fl2k_data_info_t *data_info)
-{
- if (data_info->device_error) {
- fprintf(stderr, "Device error, exiting.\n");
- do_exit = 1;
- pthread_cond_signal(&fm_cond);
- }
-
- pthread_cond_signal(&cb_cond);
-
- data_info->sampletype_signed = 1;
- data_info->r_buf = (char *)txbuf;
-}
-
-int main(int argc, char **argv)
-{
- int r, opt;
- uint32_t buf_num = 0;
- int dev_index = 0;
- pthread_attr_t attr;
- char *filename = NULL;
- int option_index = 0;
- int input_freq_specified = 0;
-
-#ifndef _WIN32
- struct sigaction sigact, sigign;
-#endif
-
- static struct option long_options[] =
- {
- {"stereo", no_argument, &stereo_flag, 1},
- {"rds", no_argument, &rds_flag, 1},
- {0, 0, 0, 0}
- };
-
- while (1) {
- opt = getopt_long(argc, argv, "d:c:f:i:s:", long_options, &option_index);
-
- /* end of options reached */
- if (opt == -1)
- break;
-
- switch (opt) {
- case 0:
- break;
- case 'd':
- dev_index = (uint32_t)atoi(optarg);
- break;
- case 'c':
- carrier_freq = (uint32_t)atof(optarg);
- break;
- case 'f':
- deviation = (uint32_t)atof(optarg);
- break;
- case 'i':
- input_freq = (uint32_t)atof(optarg);
- input_freq_specified = 1;
- break;
- case 's':
- samp_rate = (uint32_t)atof(optarg);
- break;
- default:
- usage();
- break;
- }
- }
-
- if (argc <= optind) {
- usage();
- } else {
- filename = argv[optind];
- }
-
- if (dev_index < 0) {
- exit(1);
- }
-
- if (rds_flag && input_freq_specified) {
- if (input_freq != RDS_MODULATOR_RATE) {
- fprintf(stderr, "RDS modulator only works with "
- "228 kHz audio sample rate!\n");
- exit(1);
- }
- } else if (rds_flag && !input_freq_specified) {
- input_freq = RDS_MODULATOR_RATE;
- }
-
- if (stereo_flag && input_freq < (RDS_MODULATOR_RATE/2)) {
- fprintf(stderr, "Audio sample rate needs to be at least "
- "114 kHz for stereo FM!\n");
- exit(1);
- }
-
-
- if (strcmp(filename, "-") == 0) { /* Read samples from stdin */
- file = stdin;
-#ifdef _WIN32
- _setmode(_fileno(stdin), _O_BINARY);
-#endif
- } else {
- file = fopen(filename, "rb");
- if (!file) {
- fprintf(stderr, "Failed to open %s\n", filename);
- return -ENOENT;
- }
- }
-
- /* allocate buffer */
- buf1 = malloc(FL2K_BUF_LEN);
- buf2 = malloc(FL2K_BUF_LEN);
- if (!buf1 || !buf2) {
- fprintf(stderr, "malloc error!\n");
- exit(1);
- }
-
- fmbuf = buf1;
- txbuf = buf2;
-
- /* Decoded audio */
- freqbuf = malloc(BUFFER_SAMPLES * sizeof(double));
- slopebuf = malloc(BUFFER_SAMPLES * sizeof(double));
- readpos = 0;
- writepos = 1;
-
- fprintf(stderr, "Samplerate:\t%3.2f MHz\n", (double)samp_rate/1000000);
- fprintf(stderr, "Carrier:\t%3.2f MHz\n", (double)carrier_freq/1000000);
- fprintf(stderr, "Frequencies:\t%3.2f MHz, %3.2f MHz\n",
- (double)((samp_rate - carrier_freq) / 1000000.0),
- (double)((samp_rate + carrier_freq) / 1000000.0));
-
- pthread_mutex_init(&cb_mutex, NULL);
- pthread_mutex_init(&fm_mutex, NULL);
- pthread_cond_init(&cb_cond, NULL);
- pthread_cond_init(&fm_cond, NULL);
- pthread_attr_init(&attr);
-
- fl2k_open(&dev, (uint32_t)dev_index);
- if (NULL == dev) {
- fprintf(stderr, "Failed to open fl2k device #%d.\n", dev_index);
- goto out;
- }
-
- r = pthread_create(&fm_thread, &attr, fm_worker, NULL);
- if (r < 0) {
- fprintf(stderr, "Error spawning FM worker thread!\n");
- goto out;
- }
-
- pthread_attr_destroy(&attr);
- r = fl2k_start_tx(dev, fl2k_callback, NULL, 0);
-
- /* Set the sample rate */
- r = fl2k_set_sample_rate(dev, samp_rate);
- if (r < 0)
- fprintf(stderr, "WARNING: Failed to set sample rate. %d\n", r);
-
- /* read back actual frequency */
- samp_rate = fl2k_get_sample_rate(dev);
-
- /* Calculate needed constants */
- carrier_per_signal = samp_rate / input_freq;
-
- /* Set RDS parameters */
- set_rds_pi(0x0dac);
- set_rds_ps("fl2k_fm");
- set_rds_rt("VGA FM transmitter");
-
-#ifndef _WIN32
- sigact.sa_handler = sighandler;
- sigemptyset(&sigact.sa_mask);
- sigact.sa_flags = 0;
- sigign.sa_handler = SIG_IGN;
- sigaction(SIGINT, &sigact, NULL);
- sigaction(SIGTERM, &sigact, NULL);
- sigaction(SIGQUIT, &sigact, NULL);
- sigaction(SIGPIPE, &sigign, NULL);
-#else
- SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
-#endif
-
- if (stereo_flag) {
- fm_modulator_stereo(rds_flag);
- } else {
- if (rds_flag)
- fprintf(stderr, "Warning: RDS with mono (without 19 kHz pilot"
- " tone) doesn't work with all receivers!\n");
-
- fm_modulator_mono(rds_flag);
- }
-
-out:
- fl2k_close(dev);
-
- if (file != stdin)
- fclose(file);
-
- free(freqbuf);
- free(slopebuf);
- free(buf1);
- free(buf2);
-
- return 0;
-}
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