mirror of
https://github.com/rtlsdrblog/rtl-sdr-blog.git
synced 2025-10-31 08:58:09 +01:00
rtl_fm: broken multi freq scanning
Signed-off-by: Steve Markgraf <steve@steve-m.de>
This commit is contained in:
Kyle Keen
committed by
Steve Markgraf
Steve Markgraf
parent
6a9f5c14c2
commit
defa7af74b
120
src/rtl_fm.c
120
src/rtl_fm.c
@@ -27,6 +27,7 @@
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* in-place array operations
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* wide band support
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* refactor to look like rtl_tcp
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* multiple frequency scanning
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*/
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#include <errno.h>
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@@ -55,18 +56,23 @@ static rtlsdr_dev_t *dev = NULL;
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struct fm_state
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{
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int now_r;
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int now_j;
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int pre_r;
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int pre_j;
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int prev_index;
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int downsample; /* min 4, max 256 */
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int output_scale;
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int squelch_level;
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int signal[2048]; /* 16 bit signed i/q pairs */
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int16_t signal2[2048]; /* signal has lowpass, signal2 has demod */
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int signal_len;
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FILE *file;
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int now_r;
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int now_j;
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int pre_r;
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int pre_j;
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int prev_index;
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int downsample; /* min 4, max 256 */
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int output_scale;
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int squelch_level;
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int signal[2048]; /* 16 bit signed i/q pairs */
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int16_t signal2[2048]; /* signal has lowpass, signal2 has demod */
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int signal_len;
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FILE *file;
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int edge;
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uint32_t freqs[32];
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int freq_len;
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int freq_now;
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uint32_t sample_rate;
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};
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void usage(void)
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@@ -79,6 +85,7 @@ void usage(void)
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fprintf(stderr,
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"rtl_fm, a simple narrow band FM demodulator for RTL2832 based DVB-T receivers\n\n"
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"Usage:\t -f frequency_to_tune_to [Hz]\n"
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"\t (use multiple -f for scanning !!BROKEN!!)\n"
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"\t[-s samplerate (default: 24000 Hz)]\n"
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"\t[-d device_index (default: 0)]\n"
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"\t[-g tuner_gain (default: -1dB)]\n"
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@@ -203,7 +210,8 @@ int mad(int *samples, int len, int step)
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return sum / (len * step);
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}
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void post_squelch(struct fm_state *fm)
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int post_squelch(struct fm_state *fm)
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/* returns 1 for active signal, 0 for no signal */
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{
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int i, i2, dev_r, dev_j, len, sq_l;
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/* only for small samples, big samples need chunk processing */
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@@ -212,17 +220,48 @@ void post_squelch(struct fm_state *fm)
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dev_r = mad(&(fm->signal[0]), len, 2);
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dev_j = mad(&(fm->signal[1]), len, 2);
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if ((dev_r > sq_l) || (dev_j > sq_l)) {
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return;
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return 1;
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}
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/* weak signal, kill it entirely */
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for (i=0; i<len; i++) {
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fm->signal2[i/2] = 0;
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}
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return 0;
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}
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static void optimal_settings(struct fm_state *fm, int freq, int hopping)
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{
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int r, capture_freq, capture_rate;
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fm->downsample = (1000000 / fm->sample_rate) + 1;
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fm->freq_now = freq;
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capture_rate = fm->downsample * fm->sample_rate;
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capture_freq = fm->freqs[freq] + capture_rate/4;
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capture_freq += fm->edge * fm->sample_rate / 2;
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fm->output_scale = (1<<15) / (128 * fm->downsample);
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if (fm->output_scale < 1) {
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fm->output_scale = 1;}
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fm->output_scale = 1;
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/* Set the frequency */
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r = rtlsdr_set_center_freq(dev, capture_freq);
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if (hopping) {
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return;}
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fprintf(stderr, "Oversampling by: %ix.\n", fm->downsample);
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if (r < 0) {
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fprintf(stderr, "WARNING: Failed to set center freq.\n");}
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else {
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fprintf(stderr, "Tuned to %u Hz.\n", capture_freq);}
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/* Set the sample rate */
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r = rtlsdr_set_sample_rate(dev, capture_rate);
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if (r < 0) {
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fprintf(stderr, "WARNING: Failed to set sample rate.\n");}
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}
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static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
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{
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struct fm_state *fm2;
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int sr, freq_next;
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if (!ctx) {
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return;
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}
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@@ -230,34 +269,18 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
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rotate_90(buf, len);
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low_pass(fm2, buf, len);
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fm_demod(fm2);
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post_squelch(fm2);
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sr = post_squelch(fm2);
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/* ignore under runs for now */
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fwrite(fm2->signal2, 2, fm2->signal_len/2, fm2->file);
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}
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static void optimal_settings(struct fm_state *fm, int freq, int rate, int edge)
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{
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int r, capture_freq, capture_rate;
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fm->downsample = (1000000 / rate) + 1;
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fprintf(stderr, "Oversampling by: %ix.\n", fm->downsample);
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capture_rate = fm->downsample * rate;
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capture_freq = (freq + (edge*rate/2)) + capture_rate/4;
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fm->output_scale = (1<<15) / (128 * fm->downsample);
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if (fm->output_scale < 1) {
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fm->output_scale = 1;
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if (fm2->freq_len > 1 && !sr) {
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freq_next = (fm2->freq_now + 1) % fm2->freq_len;
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optimal_settings(fm2, freq_next, 1);
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rtlsdr_reset_buffer(dev);
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//rtlsdr_read_async(dev, rtlsdr_callback, ctx,
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// DEFAULT_ASYNC_BUF_NUMBER, DEFAULT_BUF_LENGTH);
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//rtlsdr_wait_async(dev, rtlsdr_callback, (void *)0);
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//rtlsdr_wait_async(dev, rtlsdr_callback, ctx);
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}
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fm->output_scale = 1;
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/* Set the sample rate */
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r = rtlsdr_set_sample_rate(dev, capture_rate);
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if (r < 0)
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fprintf(stderr, "WARNING: Failed to set sample rate.\n");
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/* Set the frequency */
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r = rtlsdr_set_center_freq(dev, capture_freq);
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if (r < 0)
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fprintf(stderr, "WARNING: Failed to set center freq.\n");
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else
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fprintf(stderr, "Tuned to %u Hz.\n", capture_freq);
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}
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int main(int argc, char **argv)
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@@ -269,15 +292,16 @@ int main(int argc, char **argv)
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char *filename = NULL;
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int n_read;
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int r, opt;
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int i, edge = 0, gain = -10; // tenths of a dB
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int i, gain = -10; // tenths of a dB
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uint8_t *buffer;
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uint32_t dev_index = 0;
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uint32_t frequency = 100000000;
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uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
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uint32_t out_block_size = DEFAULT_BUF_LENGTH;
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int device_count;
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char vendor[256], product[256], serial[256];
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fm.freqs[0] = 100000000;
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fm.sample_rate = DEFAULT_SAMPLE_RATE;
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fm.squelch_level = 150;
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fm.freq_len = 0;
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#ifndef _WIN32
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while ((opt = getopt(argc, argv, "d:f:g:s:b:l:E::")) != -1) {
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switch (opt) {
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@@ -285,7 +309,8 @@ int main(int argc, char **argv)
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dev_index = atoi(optarg);
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break;
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case 'f':
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frequency = (uint32_t)atof(optarg);
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fm.freqs[fm.freq_len] = (uint32_t)atof(optarg);
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fm.freq_len++;
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break;
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case 'g':
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gain = (int)(atof(optarg) * 10);
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@@ -294,10 +319,10 @@ int main(int argc, char **argv)
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fm.squelch_level = (int)atof(optarg);
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break;
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case 's':
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samp_rate = (uint32_t)atof(optarg);
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fm.sample_rate = (uint32_t)atof(optarg);
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break;
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case 'E':
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edge = 1;
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fm.edge = 1;
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break;
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default:
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usage();
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@@ -316,7 +341,8 @@ int main(int argc, char **argv)
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dev_index = atoi(argv[1]);
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samp_rate = atoi(argv[2])*1000;
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gain=(int)(atof(argv[3]) * 10);
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frequency = atoi(argv[4]);
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fm.freqs[0] = atoi(argv[4]);
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fm.freq_len = 1;
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filename = argv[5];
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#endif
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out_block_size = DEFAULT_BUF_LENGTH;
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@@ -356,7 +382,7 @@ int main(int argc, char **argv)
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SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
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#endif
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optimal_settings(&fm, frequency, samp_rate, edge);
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optimal_settings(&fm, 0, 0);
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/* Set the tuner gain */
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r = rtlsdr_set_tuner_gain(dev, gain);
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