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Autodetection of minimum and maximum sample rates #64

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Autodetection of minimum and maximum sample rates #64

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43 changes: 28 additions & 15 deletions src/rtl_power.c
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Original file line number Diff line number Diff line change
Expand Up @@ -71,9 +71,6 @@
#define DEFAULT_BUF_LENGTH (1 * 16384)
#define BUFFER_DUMP DEFAULT_BUF_LENGTH

#define MAXIMUM_RATE 2800000
#define MINIMUM_RATE 1000000

static volatile int do_exit = 0;
static SoapySDRDevice *dev = NULL;
static SoapySDRStream *stream = NULL;
Expand Down Expand Up @@ -426,7 +423,7 @@ void rms_power(struct tuning_state *ts)
ts->samples += 1;
}

void frequency_range(char *arg, double crop)
void frequency_range(char *arg, double crop, uint32_t minimum_rate, uint32_t maximum_rate)
/* flesh out the tunes[] for scanning */
// do we want the fewest ranges (easy) or the fewest bins (harder)?
{
Expand Down Expand Up @@ -454,17 +451,17 @@ void frequency_range(char *arg, double crop)
for (i=1; i<1500; i++) {
bw_seen = (upper - lower) / i;
bw_used = (int64_t)((double)(bw_seen) / (1.0 - crop));
if (bw_used > MAXIMUM_RATE) {
if (bw_used > maximum_rate) {
continue;}
tune_count = i;
break;
}
/* unless small bandwidth */
if (bw_used < MINIMUM_RATE) {
if (bw_used < minimum_rate) {
tune_count = 1;
downsample = MAXIMUM_RATE / bw_used;
downsample = maximum_rate / bw_used;
if (downsample <= 0) {
fprintf(stderr, "unsupported bandwidth: MAXIMUM_RATE=%d, bw_used=%lli, downsample=%lli\n", MAXIMUM_RATE, bw_used, downsample);
fprintf(stderr, "unsupported bandwidth: MAXIMUM_RATE=%d, bw_used=%lli, downsample=%lli\n", maximum_rate, bw_used, downsample);
exit(1);
}
bw_used = bw_used * downsample;
Expand All @@ -473,7 +470,7 @@ void frequency_range(char *arg, double crop)
downsample_passes = (int)log2(downsample);
downsample = 1 << downsample_passes;
if (downsample <= 0) {
fprintf(stderr, "unsupported bandwidth: MAXIMUM_RATE=%d, downsample_passes=%lli, bw_used=%lli, downsample=%lli\n", MAXIMUM_RATE, downsample_passes, bw_used, downsample);
fprintf(stderr, "unsupported bandwidth: MAXIMUM_RATE=%d, downsample_passes=%lli, bw_used=%lli, downsample=%lli\n", maximum_rate, downsample_passes, bw_used, downsample);
exit(1);
}
bw_used = (int)((double)(bw_seen * downsample) / (1.0 - crop));
Expand All @@ -488,7 +485,7 @@ void frequency_range(char *arg, double crop)
break;}
}
/* unless giant bins */
if (max_size >= MINIMUM_RATE) {
if (max_size >= minimum_rate) {
bw_seen = max_size;
bw_used = max_size;
tune_count = (upper - lower) / bw_seen;
Expand Down Expand Up @@ -529,6 +526,7 @@ void frequency_range(char *arg, double crop)
ts->buf_len = buf_len;
}
/* report */
fprintf(stderr, "Rates: minimum %d, maximum %d\n", minimum_rate, maximum_rate);
fprintf(stderr, "Number of frequency hops: %i\n", tune_count);
fprintf(stderr, "Dongle bandwidth: %lliHz\n", bw_used);
fprintf(stderr, "Downsampling by: %llix\n", downsample);
Expand Down Expand Up @@ -838,6 +836,13 @@ int main(int argc, char **argv)
char t_str[50];
struct tm cal_time = {0};
double (*window_fn)(int, int) = rectangle;

long unsigned int minimum_rate, maximum_rate;
double *rates = NULL;
int direction = SOAPY_SDR_RX;
int channel = 0;
size_t len = 0;

freq_optarg = "";

while ((opt = getopt(argc, argv, "f:i:s:t:d:g:p:e:w:c:F:1PD:OS:R:h")) != -1) {
Expand Down Expand Up @@ -930,11 +935,6 @@ int main(int argc, char **argv)
exit(1);
}

frequency_range(freq_optarg, crop);

if (tune_count == 0) {
usage();}

if (argc <= optind) {
filename = "-";
} else {
Expand All @@ -948,6 +948,19 @@ int main(int argc, char **argv)

r = verbose_device_search(dev_query, &dev, &stream, SOAPY_SDR_CS16);

// Find maximum and minimum sampling rates for this device
rates = SoapySDRDevice_listSampleRates(dev, direction, channel, &len);
maximum_rate = minimum_rate = rates[1];
for (i = 0; i < len; ++i) {
if (rates[i] > maximum_rate) maximum_rate = rates[i];
if (rates[i] < minimum_rate) minimum_rate = rates[i];
}

frequency_range(freq_optarg, crop, minimum_rate, maximum_rate);

if (tune_count == 0) {
usage();}

if (r != 0) {
fprintf(stderr, "Failed to open sdr device matching '%s'.\n", dev_query);
exit(1);
Expand Down