mirror of
https://github.com/rtlsdrblog/rtl-sdr-blog.git
synced 2025-04-02 01:25:40 +02:00
rtl_fm: tweaks for nicer scanning
Signed-off-by: Steve Markgraf <steve@steve-m.de>
This commit is contained in:
parent
c3dde1db91
commit
d56267a42f
35
src/rtl_fm.c
35
src/rtl_fm.c
@ -51,9 +51,10 @@
|
|||||||
|
|
||||||
#define DEFAULT_SAMPLE_RATE 24000
|
#define DEFAULT_SAMPLE_RATE 24000
|
||||||
#define DEFAULT_ASYNC_BUF_NUMBER 32
|
#define DEFAULT_ASYNC_BUF_NUMBER 32
|
||||||
#define DEFAULT_BUF_LENGTH 1024
|
#define DEFAULT_BUF_LENGTH (1 * 16384)
|
||||||
#define MINIMAL_BUF_LENGTH 512
|
#define MINIMAL_BUF_LENGTH 512
|
||||||
#define MAXIMAL_BUF_LENGTH (256 * 16384)
|
#define MAXIMAL_BUF_LENGTH (256 * 16384)
|
||||||
|
#define CONSEQ_SQUELCH 4
|
||||||
|
|
||||||
static pthread_t demod_thread;
|
static pthread_t demod_thread;
|
||||||
static sem_t data_ready;
|
static sem_t data_ready;
|
||||||
@ -70,10 +71,11 @@ struct fm_state
|
|||||||
int downsample; /* min 4, max 256 */
|
int downsample; /* min 4, max 256 */
|
||||||
int output_scale;
|
int output_scale;
|
||||||
int squelch_level;
|
int squelch_level;
|
||||||
|
int squelch_hits;
|
||||||
uint8_t buf[DEFAULT_BUF_LENGTH];
|
uint8_t buf[DEFAULT_BUF_LENGTH];
|
||||||
uint32_t buf_len;
|
uint32_t buf_len;
|
||||||
int signal[2048]; /* 16 bit signed i/q pairs */
|
int signal[DEFAULT_BUF_LENGTH]; /* 16 bit signed i/q pairs */
|
||||||
int16_t signal2[2048]; /* signal has lowpass, signal2 has demod */
|
int16_t signal2[DEFAULT_BUF_LENGTH]; /* signal has lowpass, signal2 has demod */
|
||||||
int signal_len;
|
int signal_len;
|
||||||
FILE *file;
|
FILE *file;
|
||||||
int edge;
|
int edge;
|
||||||
@ -101,7 +103,7 @@ void usage(void)
|
|||||||
"\t[-E freq sets lower edge (default: center)]\n"
|
"\t[-E freq sets lower edge (default: center)]\n"
|
||||||
"\tfilename (a '-' dumps samples to stdout)\n\n"
|
"\tfilename (a '-' dumps samples to stdout)\n\n"
|
||||||
"Produces signed 16 bit ints, use Sox to hear them.\n"
|
"Produces signed 16 bit ints, use Sox to hear them.\n"
|
||||||
"\trtl_fm ... | play -t raw -r 24k -e signed-integer -b 16 -c 1 -\n\n");
|
"\trtl_fm ... | play -t raw -r 24k -e signed-integer -b 16 -c 1 -V1 -\n\n");
|
||||||
#endif
|
#endif
|
||||||
exit(1);
|
exit(1);
|
||||||
}
|
}
|
||||||
@ -228,12 +230,14 @@ int post_squelch(struct fm_state *fm)
|
|||||||
dev_r = mad(&(fm->signal[0]), len, 2);
|
dev_r = mad(&(fm->signal[0]), len, 2);
|
||||||
dev_j = mad(&(fm->signal[1]), len, 2);
|
dev_j = mad(&(fm->signal[1]), len, 2);
|
||||||
if ((dev_r > sq_l) || (dev_j > sq_l)) {
|
if ((dev_r > sq_l) || (dev_j > sq_l)) {
|
||||||
|
fm->squelch_hits = 0;
|
||||||
return 1;
|
return 1;
|
||||||
}
|
}
|
||||||
/* weak signal, kill it entirely */
|
/* weak signal, kill it entirely */
|
||||||
for (i=0; i<len; i++) {
|
for (i=0; i<len; i++) {
|
||||||
fm->signal2[i/2] = 0;
|
fm->signal2[i/2] = 0;
|
||||||
}
|
}
|
||||||
|
fm->squelch_hits++;
|
||||||
return 0;
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
@ -266,19 +270,20 @@ static void optimal_settings(struct fm_state *fm, int freq, int hopping)
|
|||||||
|
|
||||||
}
|
}
|
||||||
|
|
||||||
void full_demod(unsigned char *buf, uint32_t len, struct fm_state *fm2)
|
void full_demod(unsigned char *buf, uint32_t len, struct fm_state *fm)
|
||||||
{
|
{
|
||||||
int sr, freq_next;
|
int sr, freq_next;
|
||||||
rotate_90(buf, len);
|
rotate_90(buf, len);
|
||||||
low_pass(fm2, buf, len);
|
low_pass(fm, buf, len);
|
||||||
fm_demod(fm2);
|
fm_demod(fm);
|
||||||
sr = post_squelch(fm2);
|
sr = post_squelch(fm);
|
||||||
/* ignore under runs for now */
|
/* ignore under runs for now */
|
||||||
fwrite(fm2->signal2, 2, fm2->signal_len/2, fm2->file);
|
fwrite(fm->signal2, 2, fm->signal_len/2, fm->file);
|
||||||
if (fm2->freq_len > 1 && !sr) {
|
if (fm->freq_len > 1 && !sr && fm->squelch_hits > CONSEQ_SQUELCH) {
|
||||||
freq_next = (fm2->freq_now + 1) % fm2->freq_len;
|
freq_next = (fm->freq_now + 1) % fm->freq_len;
|
||||||
optimal_settings(fm2, freq_next, 1);
|
optimal_settings(fm, freq_next, 1);
|
||||||
// wait for settling and dump buffer
|
fm->squelch_hits = CONSEQ_SQUELCH + 1; /* hair trigger */
|
||||||
|
/* wait for settling and dump buffer */
|
||||||
usleep(5000);
|
usleep(5000);
|
||||||
rtlsdr_read_sync(dev, NULL, 4096, NULL);
|
rtlsdr_read_sync(dev, NULL, 4096, NULL);
|
||||||
}
|
}
|
||||||
@ -293,7 +298,8 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
|
|||||||
if (!ctx) {
|
if (!ctx) {
|
||||||
return;}
|
return;}
|
||||||
fm2 = (struct fm_struct*)(ctx); // warning?
|
fm2 = (struct fm_struct*)(ctx); // warning?
|
||||||
//full_demod(buf, len, fm2);
|
/* single threaded uses 25% less CPU? */
|
||||||
|
/* full_demod(buf, len, fm2); */
|
||||||
memcpy(fm2->buf, buf, len);
|
memcpy(fm2->buf, buf, len);
|
||||||
fm2->buf_len = len;
|
fm2->buf_len = len;
|
||||||
sem_getvalue(&data_ready, &dr_val);
|
sem_getvalue(&data_ready, &dr_val);
|
||||||
@ -377,7 +383,6 @@ int main(int argc, char **argv)
|
|||||||
#endif
|
#endif
|
||||||
|
|
||||||
buffer = malloc(DEFAULT_BUF_LENGTH * sizeof(uint8_t));
|
buffer = malloc(DEFAULT_BUF_LENGTH * sizeof(uint8_t));
|
||||||
//buffer = fm.buf;
|
|
||||||
|
|
||||||
device_count = rtlsdr_get_device_count();
|
device_count = rtlsdr_get_device_count();
|
||||||
if (!device_count) {
|
if (!device_count) {
|
||||||
|
Loading…
x
Reference in New Issue
Block a user