diff options
| -rw-r--r-- | src/rtl_fm.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/src/rtl_fm.c b/src/rtl_fm.c index 1110cb1..b6c24c0 100644 --- a/src/rtl_fm.c +++ b/src/rtl_fm.c @@ -83,6 +83,7 @@ void usage(void) "\t[-d device_index (default: 0)]\n" "\t[-g tuner_gain (default: -1dB)]\n" "\t[-l squelch_level (default: 150)]\n" + "\t[-E freq sets lower edge (default: center)]\n" "\tfilename (a '-' dumps samples to stdout)\n\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"); @@ -234,13 +235,13 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx) fwrite(fm2->signal2, 2, fm2->signal_len/2, fm2->file); } -static void optimal_settings(struct fm_state *fm, int freq, int rate) +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 + capture_rate/4; + 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; @@ -268,7 +269,7 @@ int main(int argc, char **argv) char *filename = NULL; int n_read; int r, opt; - int i, gain = -10; // tenths of a dB + int i, edge = 0, gain = -10; // tenths of a dB uint8_t *buffer; uint32_t dev_index = 0; uint32_t frequency = 100000000; @@ -278,7 +279,7 @@ int main(int argc, char **argv) char vendor[256], product[256], serial[256]; fm.squelch_level = 150; #ifndef _WIN32 - while ((opt = getopt(argc, argv, "d:f:g:s:b:l:S::")) != -1) { + while ((opt = getopt(argc, argv, "d:f:g:s:b:l:E::")) != -1) { switch (opt) { case 'd': dev_index = atoi(optarg); @@ -295,6 +296,9 @@ int main(int argc, char **argv) case 's': samp_rate = (uint32_t)atof(optarg); break; + case 'E': + edge = 1; + break; default: usage(); break; @@ -352,7 +356,7 @@ int main(int argc, char **argv) SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE ); #endif - optimal_settings(&fm, frequency, samp_rate); + optimal_settings(&fm, frequency, samp_rate, edge); /* Set the tuner gain */ r = rtlsdr_set_tuner_gain(dev, gain); |