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-rw-r--r--src/rtl_fm.c120
1 files changed, 73 insertions, 47 deletions
diff --git a/src/rtl_fm.c b/src/rtl_fm.c
index b6c24c0..fc58497 100644
--- a/src/rtl_fm.c
+++ b/src/rtl_fm.c
@@ -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);
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-18 21:22:09 +0000