static inline boost::int16_t to_int16(T1 high, T2 low) {
return to_int16(static_cast<unsigned char>(high), static_cast<unsigned char>(low));
}
static inline boost::int16_t to_int16(const Byte *buf) {
return to_int16(buf[0], buf[1]);
}
// main program
int main (int argc, char **argv)
{
// command-line options
int verbose = 1;
int ppm_error = 0;
int gain = 0;
float rx_resamp_rate;
float bandwidth = 800e3f;
int r, n_read;
uint32_t frequency = 100000000;
uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
uint32_t out_block_size = DEFAULT_BUF_LENGTH;
uint8_t *buffer;
complex float *buffer_norm;
int dev_index = 0;
int dev_given = 0;
struct sigaction sigact;
normalizer_t *norm;
float kf = 0.1f; // modulation factor
liquid_freqdem_type type = LIQUID_FREQDEM_DELAYCONJ;
//
int d;
while ((d = getopt(argc,argv,"hf:b:B:G:p:s:")) != EOF) {
switch (d) {
case 'h': usage(); return 0;
case 'f': frequency = atof(optarg); break;
case 'b': bandwidth = atof(optarg); break;
case 'B': out_block_size = (uint32_t)atof(optarg); break;
case 'G': gain = (int)(atof(optarg) * 10); break;
case 'p': ppm_error = atoi(optarg); break;
case 's': samp_rate = (uint32_t)atofs(optarg); break;
case 'd':
dev_index = verbose_device_search(optarg);
dev_given = 1;
break;
default: usage(); return 1;
}
}
if (!dev_given) {
dev_index = verbose_device_search("0");
}
if (dev_index < 0) {
exit(1);
}
r = rtlsdr_open(&dev, (uint32_t)dev_index);
if (r < 0) {
fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dev_index);
exit(1);
}
sigact.sa_handler = sighandler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = 0;
sigaction(SIGINT, &sigact, NULL);
sigaction(SIGTERM, &sigact, NULL);
sigaction(SIGQUIT, &sigact, NULL);
sigaction(SIGPIPE, &sigact, NULL);
/* Set the sample rate */
verbose_set_sample_rate(dev, samp_rate);
/* Set the frequency */
verbose_set_frequency(dev, frequency);
if (0 == gain) {
/* Enable automatic gain */
verbose_auto_gain(dev);
} else {
/* Enable manual gain */
gain = nearest_gain(dev, gain);
verbose_gain_set(dev, gain);
}
verbose_ppm_set(dev, ppm_error);
rx_resamp_rate = bandwidth/samp_rate;
printf("frequency : %10.4f [MHz]\n", frequency*1e-6f);
printf("bandwidth : %10.4f [kHz]\n", bandwidth*1e-3f);
printf("sample rate : %10.4f kHz = %10.4f kHz * %8.6f\n",
samp_rate * 1e-3f,
bandwidth * 1e-3f,
1.0f / rx_resamp_rate);
printf("verbosity : %s\n", (verbose?"enabled":"disabled"));
unsigned int i,j;
// add arbitrary resampling component
msresamp_crcf resamp = msresamp_crcf_create(rx_resamp_rate, 60.0f);
assert(resamp);
//allocate recv buffer
buffer = malloc(out_block_size * sizeof(uint8_t));
assert(buffer);
buffer_norm = malloc(out_block_size * sizeof(complex float));
assert(buffer_norm);
// create buffer for arbitrary resamper output
int b_len = ((int)(out_block_size * rx_resamp_rate) + 64) >> 1;
complex float buffer_resamp[b_len];
int16_t buffer_demod[b_len];
debug("resamp_buffer_len: %d\n", b_len);
norm = normalizer_create();
verbose_reset_buffer(dev);
freqdem dem = freqdem_create(kf,type);
while (!do_exit) {
// grab data from device
r = rtlsdr_read_sync(dev, buffer, out_block_size, &n_read);
if (r < 0) {
fprintf(stderr, "WARNING: sync read failed.\n");
break;
}
if ((bytes_to_read > 0) && (bytes_to_read < (uint32_t)n_read)) {
n_read = bytes_to_read;
do_exit = 1;
}
// push data through arbitrary resampler and give to frame synchronizer
// TODO : apply bandwidth-dependent gain
for (i=0; i<n_read/2; i++) {
// grab sample from usrp buffer
buffer_norm[i] = normalizer_normalize(norm, *((uint16_t*)buffer+i));
}
// push through resampler (one at a time)
unsigned int nw;
float demod;
msresamp_crcf_execute(resamp, buffer_norm, n_read/2, buffer_resamp, &nw);
for(j=0;j<nw;j++)
{
freqdem_demodulate(dem, buffer_resamp[j], &demod);
buffer_demod[j] = to_int16(demod);
}
if (fwrite(buffer_demod, 2, nw, stdout) != (size_t)nw) {
fprintf(stderr, "Short write, samples lost, exiting!\n");
break;
}
if ((uint32_t)n_read < out_block_size) {
fprintf(stderr, "Short read, samples lost, exiting!\n");
break;
}
if (bytes_to_read > 0)
bytes_to_read -= n_read;
}
// destroy objects
freqdem_destroy(dem);
normalizer_destroy(&norm);
msresamp_crcf_destroy(resamp);
rtlsdr_close(dev);
free (buffer);
return 0;
}
