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-rw-r--r--src/rtl_fm.c27
1 files changed, 18 insertions, 9 deletions
diff --git a/src/rtl_fm.c b/src/rtl_fm.c
index eb7190a..b761c0e 100644
--- a/src/rtl_fm.c
+++ b/src/rtl_fm.c
@@ -59,7 +59,8 @@
#define DEFAULT_BUF_LENGTH (1 * 16384)
#define MINIMAL_BUF_LENGTH 512
#define MAXIMAL_BUF_LENGTH (256 * 16384)
-#define CONSEQ_SQUELCH 4
+#define CONSEQ_SQUELCH 4
+#define AUTO_GAIN -100
static pthread_t demod_thread;
static sem_t data_ready;
@@ -103,7 +104,7 @@ void usage(void)
"\t (use multiple -f for scanning)\n"
"\t[-s samplerate (default: 24000 Hz)]\n"
"\t[-d device_index (default: 0)]\n"
- "\t[-g tuner_gain (default: -1dB)]\n"
+ "\t[-g tuner_gain (default: automatic)]\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"
@@ -311,8 +312,8 @@ int mad(int *samples, int len, int step)
/* mean average deviation */
{
int i=0, sum=0, ave=0;
- if (len == 0)
- {return 0;}
+ if (len == 0)
+ {return 0;}
for (i=0; i<len; i+=step) {
sum += samples[i];
}
@@ -369,7 +370,7 @@ static void optimal_settings(struct fm_state *fm, int freq, int hopping)
fprintf(stderr, "WARNING: Failed to set center freq.\n");}
else {
fprintf(stderr, "Tuned to %u Hz.\n", capture_freq);}
-
+
/* Set the sample rate */
fprintf(stderr, "Sampling at %u Hz.\n", capture_rate);
r = rtlsdr_set_sample_rate(dev, (uint32_t)capture_rate);
@@ -439,7 +440,7 @@ 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, gain = AUTO_GAIN; // tenths of a dB
uint8_t *buffer;
uint32_t dev_index = 0;
int device_count;
@@ -538,11 +539,19 @@ int main(int argc, char **argv)
build_fir(&fm);
/* Set the tuner gain */
- r = rtlsdr_set_tuner_gain(dev, gain);
- if (r < 0)
+ if (gain == AUTO_GAIN) {
+ r = rtlsdr_set_tuner_gain_mode(dev, 0);
+ } else {
+ r = rtlsdr_set_tuner_gain_mode(dev, 1);
+ r = rtlsdr_set_tuner_gain(dev, gain);
+ }
+ if (r != 0) {
fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
- else
+ } else if (gain == AUTO_GAIN) {
+ fprintf(stderr, "Tuner gain set to automatic.\n");
+ } else {
fprintf(stderr, "Tuner gain set to %0.2f dB.\n", gain/10.0);
+ }
if(strcmp(filename, "-") == 0) { /* Write samples to stdout */
fm.file = stdout;