MightyPork
/
rtl-sdr
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

rtl_fm: broken multi freq scanning

Browse Source 
Signed-off-by: Steve Markgraf <steve@steve-m.de>
master
Kyle Keen 13 years ago committed by Steve Markgraf
parent 6a9f5c14c2
commit defa7af74b
1 changed files with 73 additions and 47 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 120
      src/rtl_fm.c

120
src/rtl_fm.c
Unescape View File

@ -27,6 +27,7 @@
* in-place array operations
* wide band support
* refactor to look like rtl_tcp
* multiple frequency scanning
*/
#include <errno.h>
@ -55,18 +56,23 @@ static rtlsdr_dev_t *dev = NULL;
struct fm_state
{
int now_r;
int now_j;
int pre_r;
int pre_j;
int prev_index;
int downsample; /* min 4, max 256 */
int output_scale;
int squelch_level;
int signal[2048]; /* 16 bit signed i/q pairs */
int16_t signal2[2048]; /* signal has lowpass, signal2 has demod */
int signal_len;
FILE *file;
int now_r;
int now_j;
int pre_r;
int pre_j;
int prev_index;
int downsample; /* min 4, max 256 */
int output_scale;
int squelch_level;
int signal[2048]; /* 16 bit signed i/q pairs */
int16_t signal2[2048]; /* signal has lowpass, signal2 has demod */
int signal_len;
FILE *file;
int edge;
uint32_t freqs[32];
int freq_len;
int freq_now;
uint32_t sample_rate;
};
void usage(void)
@ -79,6 +85,7 @@ void usage(void)
fprintf(stderr,
"rtl_fm, a simple narrow band FM demodulator for RTL2832 based DVB-T receivers\n\n"
"Usage:\t -f frequency_to_tune_to [Hz]\n"
"\t (use multiple -f for scanning !!BROKEN!!)\n"
"\t[-s samplerate (default: 24000 Hz)]\n"
"\t[-d device_index (default: 0)]\n"
"\t[-g tuner_gain (default: -1dB)]\n"
@ -203,7 +210,8 @@ int mad(int *samples, int len, int step)
return sum / (len * step);
}
void post_squelch(struct fm_state *fm)
int post_squelch(struct fm_state *fm)
/* returns 1 for active signal, 0 for no signal */
{
int i, i2, dev_r, dev_j, len, sq_l;
/* only for small samples, big samples need chunk processing */
@ -212,17 +220,48 @@ void post_squelch(struct fm_state *fm)
dev_r = mad(&(fm->signal[0]), len, 2);
dev_j = mad(&(fm->signal[1]), len, 2);
if ((dev_r > sq_l) || (dev_j > sq_l)) {
return;
return 1;
}
/* weak signal, kill it entirely */
for (i=0; i<len; i++) {
fm->signal2[i/2] = 0;
}
return 0;
}
static void optimal_settings(struct fm_state *fm, int freq, int hopping)
{
int r, capture_freq, capture_rate;
fm->downsample = (1000000 / fm->sample_rate) + 1;
fm->freq_now = freq;
capture_rate = fm->downsample * fm->sample_rate;
capture_freq = fm->freqs[freq] + capture_rate/4;
capture_freq += fm->edge * fm->sample_rate / 2;
fm->output_scale = (1<<15) / (128 * fm->downsample);
if (fm->output_scale < 1) {
fm->output_scale = 1;}
fm->output_scale = 1;
/* Set the frequency */
r = rtlsdr_set_center_freq(dev, capture_freq);
if (hopping) {
return;}
fprintf(stderr, "Oversampling by: %ix.\n", fm->downsample);
if (r < 0) {
fprintf(stderr, "WARNING: Failed to set center freq.\n");}
else {
fprintf(stderr, "Tuned to %u Hz.\n", capture_freq);}
/* Set the sample rate */
r = rtlsdr_set_sample_rate(dev, capture_rate);
if (r < 0) {
fprintf(stderr, "WARNING: Failed to set sample rate.\n");}
}
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{
struct fm_state *fm2;
int sr, freq_next;
if (!ctx) {
return;
}
@ -230,34 +269,18 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
rotate_90(buf, len);
low_pass(fm2, buf, len);
fm_demod(fm2);
post_squelch(fm2);
sr = post_squelch(fm2);
/* ignore under runs for now */
fwrite(fm2->signal2, 2, fm2->signal_len/2, fm2->file);
}
static void optimal_settings(struct fm_state *fm, int freq, int rate, int edge)
{
int r, capture_freq, capture_rate;
fm->downsample = (1000000 / rate) + 1;
fprintf(stderr, "Oversampling by: %ix.\n", fm->downsample);
capture_rate = fm->downsample * rate;
capture_freq = (freq + (edge*rate/2)) + capture_rate/4;
fm->output_scale = (1<<15) / (128 * fm->downsample);
if (fm->output_scale < 1) {
fm->output_scale = 1;
if (fm2->freq_len > 1 && !sr) {
freq_next = (fm2->freq_now + 1) % fm2->freq_len;
optimal_settings(fm2, freq_next, 1);
rtlsdr_reset_buffer(dev);
//rtlsdr_read_async(dev, rtlsdr_callback, ctx,
// DEFAULT_ASYNC_BUF_NUMBER, DEFAULT_BUF_LENGTH);
//rtlsdr_wait_async(dev, rtlsdr_callback, (void *)0);
//rtlsdr_wait_async(dev, rtlsdr_callback, ctx);
}
fm->output_scale = 1;
/* Set the sample rate */
r = rtlsdr_set_sample_rate(dev, capture_rate);
if (r < 0)
fprintf(stderr, "WARNING: Failed to set sample rate.\n");
/* Set the frequency */
r = rtlsdr_set_center_freq(dev, capture_freq);
if (r < 0)
fprintf(stderr, "WARNING: Failed to set center freq.\n");
else
fprintf(stderr, "Tuned to %u Hz.\n", capture_freq);
}
int main(int argc, char **argv)
@ -269,15 +292,16 @@ int main(int argc, char **argv)
char *filename = NULL;
int n_read;
int r, opt;
int i, edge = 0, gain = -10; // tenths of a dB
int i, gain = -10; // tenths of a dB
uint8_t *buffer;
uint32_t dev_index = 0;
uint32_t frequency = 100000000;
uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
uint32_t out_block_size = DEFAULT_BUF_LENGTH;
int device_count;
char vendor[256], product[256], serial[256];
fm.freqs[0] = 100000000;
fm.sample_rate = DEFAULT_SAMPLE_RATE;
fm.squelch_level = 150;
fm.freq_len = 0;
#ifndef _WIN32
while ((opt = getopt(argc, argv, "d:f:g:s:b:l:E::")) != -1) {
switch (opt) {
@ -285,7 +309,8 @@ int main(int argc, char **argv)
dev_index = atoi(optarg);
break;
case 'f':
frequency = (uint32_t)atof(optarg);
fm.freqs[fm.freq_len] = (uint32_t)atof(optarg);
fm.freq_len++;
break;
case 'g':
gain = (int)(atof(optarg) * 10);
@ -294,10 +319,10 @@ int main(int argc, char **argv)
fm.squelch_level = (int)atof(optarg);
break;
case 's':
samp_rate = (uint32_t)atof(optarg);
fm.sample_rate = (uint32_t)atof(optarg);
break;
case 'E':
edge = 1;
fm.edge = 1;
break;
default:
usage();
@ -316,7 +341,8 @@ int main(int argc, char **argv)
dev_index = atoi(argv[1]);
samp_rate = atoi(argv[2])*1000;
gain=(int)(atof(argv[3]) * 10);
frequency = atoi(argv[4]);
fm.freqs[0] = atoi(argv[4]);
fm.freq_len = 1;
filename = argv[5];
#endif
out_block_size = DEFAULT_BUF_LENGTH;
@ -356,7 +382,7 @@ int main(int argc, char **argv)
SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
#endif
optimal_settings(&fm, frequency, samp_rate, edge);
optimal_settings(&fm, 0, 0);
/* Set the tuner gain */
r = rtlsdr_set_tuner_gain(dev, gain);

Write Preview
Loading…
Cancel
Save