Software to turn the RTL2832U into a SDR receiver
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rtl-sdr/src/main.c

146 lines
3.3 KiB

/*
* rtl-sdr, a poor man's SDR using a Realtek RTL2832 based DVB-stick
* Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de>
*
* 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 <errno.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <unistd.h>
#include "rtl-sdr.h"
#define READLEN (16 * 16384)
static int do_exit = 0;
void usage(void)
{
printf("rtl-sdr, an I/Q recorder for RTL2832 based DVB-T receivers\n\n"
"Usage:\t -f frequency to tune to [Hz]\n"
"\t[-s samplerate (default: 2048000 Hz)]\n"
"\toutput filename\n");
exit(1);
}
static void sighandler(int signum)
{
do_exit = 1;
}
int main(int argc, char **argv)
{
struct sigaction sigact;
int r, opt;
char *filename = NULL;
uint32_t frequency = 0, samp_rate = 2048000;
uint8_t buffer[READLEN];
uint32_t n_read;
FILE *file;
rtlsdr_dev_t *dev = NULL;
while ((opt = getopt(argc, argv, "f:s:")) != -1) {
switch (opt) {
case 'f':
frequency = atoi(optarg);
break;
case 's':
samp_rate = atoi(optarg);
break;
default:
usage();
break;
}
}
if (argc <= optind) {
usage();
} else {
filename = argv[optind];
}
rtlsdr_init();
int device_count = rtlsdr_get_device_count();
if (!device_count) {
fprintf(stderr, "No supported devices found.\n");
exit(1);
}
printf("Found %d device(s).\n", device_count);
dev = rtlsdr_open(0); /* open the first device */
if (NULL == dev) {
fprintf(stderr, "Failed to open rtlsdr device.\n");
exit(1);
}
sigact.sa_handler = sighandler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = 0;
sigaction(SIGINT, &sigact, NULL);
sigaction(SIGTERM, &sigact, NULL);
sigaction(SIGQUIT, &sigact, NULL);
/* Set the sample rate */
r = rtlsdr_set_sample_rate(dev, samp_rate);
if (r < 0) {
fprintf(stderr, "WARNING: Failed to set sample rate.\n");
}
/* Set the frequency */
r = rtlsdr_set_center_freq(dev, frequency);
if (r < 0) {
fprintf(stderr, "WARNING: Failed to set center freq.\n");
}
file = fopen(filename, "wb");
if (!file) {
printf("Failed to open %s\n", filename);
goto out;
}
/* Reset endpoint before we start reading from it */
r = rtlsdr_reset_buffer(dev);
if (r < 0) {
fprintf(stderr, "WARNING: Failed to reset buffers.\n");
}
printf("Reading samples...\n");
while (!do_exit) {
r = rtlsdr_read_sync(dev, buffer, READLEN, &n_read);
if (r < 0) {
fprintf(stderr, "WARNING: sync read failed.\n");
}
fwrite(buffer, n_read, 1, file);
if (n_read < READLEN) {
printf("Short read, samples lost, exiting!\n");
break;
}
}
fclose(file);
rtlsdr_exit();
out:
return r >= 0 ? r : -r;
}