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rtl_fm: broken multi freq scanning

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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
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  1. 96
      src/rtl_fm.c

96
src/rtl_fm.c
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@ -27,6 +27,7 @@
* in-place array operations
* wide band support
* refactor to look like rtl_tcp
* multiple frequency scanning
*/
#include <errno.h>
@ -67,6 +68,11 @@ struct fm_state
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);
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);
}
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;
}
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);

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