Refactor AM modulator into IQ modulator (work in progress)

1 files changed, 0 insertions, 499 deletions

diff --git a/src/fl2k_am.c b/src/fl2k_am.c
deleted file mode 100644
index de9b01e..0000000
--- a/src/fl2k_am.c
+++ /dev/null
@@ -1,499 +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		2048
-
-fl2k_dev_t *dev = NULL;
-int do_exit = 0;
-
-pthread_t am_thread;
-pthread_mutex_t cb_mutex;
-pthread_mutex_t am_mutex;
-pthread_cond_t cb_cond;
-pthread_cond_t am_cond;
-
-FILE *file;
-int8_t *txbuf = NULL;
-int8_t *ambuf = NULL;
-int8_t *buf1 = NULL;
-int8_t *buf2 = NULL;
-
-uint32_t samp_rate = 100000000;
-
-int carrier_freq = 1440000;
-int carrier_per_signal;
-int input_freq = 44100;
-
-double mod_index = 0.9;
-double *ampbuf;
-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: 1440 kHz)]\n"
-		"\t[-m Modulation index (default: 0.9)]\n"
-		"\t[-i input audio sample rate (default: 44100 Hz for mono FM)]\n"
-		"\t[-s samplerate in Hz (default: 100 MS/s)]\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(&am_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(&am_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)
-
-int16_t sine_table[SIN_TABLE_LEN];
-int sine_table_init = 0;
-
-typedef struct {
-	double sample_freq;
-	double freq;
-	unsigned long int phase;
-	unsigned long int phase_step;
-	int32_t amplitude;
-	double ampslope;
-} dds_t;
-
-static inline void dds_set_freq(dds_t *dds, double freq)
-{
-	dds->freq = freq;
-	dds->phase_step = (freq / dds->sample_freq) * 2 * M_PI * ANG_INCR;
-}
-
-static inline void dds_set_amp(dds_t *dds, double amplitude, double ampslope)
-{
-	dds->amplitude = (int32_t) (amplitude * 32768.0);
-	dds->ampslope  = ampslope;
-}
-
-dds_t dds_init(double sample_freq, double freq, double phase, double amp)
-{
-	dds_t dds;
-	int i;
-
-	dds.sample_freq = sample_freq;
-	dds.phase = phase * ANG_INCR;
-	dds_set_freq(&dds, freq);
-	dds_set_amp(&dds, amp, 0);
-	/* Initialize sine table, prescaled for 16 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) * 32767;
-
-		sine_table_init = 1;
-	}
-
-	return dds;
-}
-
-static inline int8_t dds_real(dds_t *dds)
-{
-	int tmp;
-	int32_t amp;
-	int8_t amp8;
-
-	// advance dds generator
-	tmp = dds->phase >> SIN_TABLE_SHIFT;
-	dds->phase += dds->phase_step;
-	dds->phase &= 0xffffffff;
-
-	//amp = 255;
-	amp = dds->amplitude;		// 0..15
-	amp = amp * sine_table[tmp];	// 0..31
-	amp8 = (int8_t) (amp >> 24);
-	//dds->amplitude += dds->ampslope;
-	return amp8;
-}
-
-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 amplitude information
- * in the amp buffer */
-static void *am_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, 1);
-
-	while (!do_exit) {
-		dds_set_amp(&carrier, ampbuf[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, &ambuf[len], readlen);
-
-			if (buf_prefilled) {
-				/* swap buffers */
-				tmp_ptr = ambuf;
-				ambuf = txbuf;
-				txbuf = tmp_ptr;
-				pthread_cond_wait(&cb_cond, &cb_mutex);
-			}
-
-			dds_real_buf(&carrier, ambuf, remaining);
-			len = remaining;
-
-			buf_prefilled = 1;
-		} else {
-			dds_real_buf(&carrier, &ambuf[len], carrier_per_signal);
-			len += carrier_per_signal;
-		}
-		pthread_cond_signal(&am_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_am(int lastwritepos, double lastamp, double sample)
-{
-	double amp, slope;
-
-	/* Calculate modulator amplitude at this point to lessen
-	 * the calculations needed in the signal generator */
-	amp = 1 - ((1+sample) * mod_index)/2;
-
-	/* 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 amplitude
-	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 = amp - lastamp;
-	slope /= carrier_per_signal;
-	slopebuf[lastwritepos] = slope;
-	ampbuf[writepos]       = amp;
-
-	return amp;
-}
-
-void am_modulator()
-{
-	unsigned int i;
-	size_t len;
-	double freq;
-	double lastamp = 0;
-	int16_t audio_buf[AUDIO_BUF_SIZE];
-	uint32_t lastwritepos = writepos;
-	double sample;
-
-	while (!do_exit) {
-		len = writelen(AUDIO_BUF_SIZE);
-		if (len > 1) {
-			len = fread(audio_buf, 2, len, file);
-
-			if (len == 0){
-				if(ferror(file)){
-					do_exit = 1;
-				}
-			}
-
-			for (i = 0; i < len; i++) {
-				sample = (double) audio_buf[i] / 32768.0;
-
-				/* Modulate and buffer the sample */
-				lastamp = modulate_sample_am(lastwritepos, lastamp, sample);
-				lastwritepos = writepos++;
-				writepos %= BUFFER_SAMPLES;
-			}
-		} else {
-			pthread_cond_wait(&am_cond, &am_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(&am_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[] =
-	{
-		{0, 0, 0, 0}
-	};
-
-	while (1) {
-		opt = getopt_long(argc, argv, "d:c:m: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 'i':
-			input_freq = (uint32_t)atof(optarg);
-			input_freq_specified = 1;
-			break;
-		case 'm':
-			mod_index = atof(optarg);
-			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 (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);
-	}
-
-	ambuf = buf1;
-	txbuf = buf2;
-
-	/* Decoded audio */
-	slopebuf 	= malloc(BUFFER_SAMPLES * sizeof(double));
-	ampbuf  	= 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%5.0f kHz\n", (double)carrier_freq/1000);
-	fprintf(stderr, "Mod Index:\t%2.1f %%\n", (double)mod_index*100);
-
-	pthread_mutex_init(&cb_mutex, NULL);
-	pthread_mutex_init(&am_mutex, NULL);
-	pthread_cond_init(&cb_cond, NULL);
-	pthread_cond_init(&am_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(&am_thread, &attr, am_worker, NULL);
-	if (r < 0) {
-		fprintf(stderr, "Error spawning AM 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;
-
-#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
-
-	am_modulator();
-
-out:
-	fl2k_close(dev);
-
-	if (file != stdin)
-		fclose(file);
-
-	free(ampbuf);
-	free(slopebuf);
-	free(buf1);
-	free(buf2);
-
-	return 0;
-}