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first pass at integrating fsk_demod, works most of the time. Some fine tuning might be required, e.g. freq range or threaded processing

master
David 2020-07-10 10:10:31 +09:30
parent 837b3ae3e2
commit 8bc4b3620a
1 changed files with 59 additions and 7 deletions
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66
src/rtl_fsk.c
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@ -16,6 +16,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
@ -35,7 +36,7 @@
#include "convenience/convenience.h"
#include "fsk.h"
#define DEFAULT_SAMPLE_RATE 2048000
#define DEFAULT_SAMPLE_RATE 240000
#define DEFAULT_BUF_LENGTH (16 * 16384)
#define MINIMAL_BUF_LENGTH 512
#define MAXIMAL_BUF_LENGTH (256 * 16384)
@ -43,20 +44,24 @@
static int do_exit = 0;
static uint32_t bytes_to_read = 0;
static rtlsdr_dev_t *dev = NULL;
static struct FSK *fsk;
static uint32_t out_block_size = DEFAULT_BUF_LENGTH;
static unsigned char *rawbuf;
static size_t nrawbuf = 0;
void usage(void)
{
fprintf(stderr,
"rtl_fsk, a FSK demodulator for RTL2832 based DVB-T receivers\n\n"
"Usage:\t -f frequency_to_tune_to [Hz]\n"
"\t[-s samplerate (default: 2048000 Hz)]\n"
"\t[-s samplerate (default: %d Hz)]\n"
"\t[-d device_index (default: 0)]\n"
"\t[-g gain (default: 0 for auto)]\n"
"\t[-p ppm_error (default: 0)]\n"
"\t[-b output_block_size (default: 16 * 16384)]\n"
"\t[-n number of samples to read (default: 0, infinite)]\n"
"\t[-S force sync output (default: async)]\n"
"\tfilename (a '-' dumps samples to stdout)\n\n");
"\tfilename (a '-' dumps bits to stdout)\n\n", DEFAULT_SAMPLE_RATE);
exit(1);
}
@ -83,6 +88,10 @@ static void sighandler(int signum)
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{
unsigned char *pout;
unsigned int i;
unsigned char bitbuf[fsk->Nbits];
if (ctx) {
if (do_exit)
return;
@ -93,11 +102,39 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
rtlsdr_cancel_async(dev);
}
/*
if (fwrite(buf, 1, len, (FILE*)ctx) != len) {
fprintf(stderr, "Short write, samples lost, exiting!\n");
rtlsdr_cancel_async(dev);
}
*/
/* append to existing samples in rawbuf */
memcpy(&rawbuf[nrawbuf],buf,len);
nrawbuf += len;
assert(nrawbuf < 2*out_block_size);
/* process as many samples in rawbuf as possible */
pout = rawbuf;
while(nrawbuf >= 2*fsk_nin(fsk)) {
COMP modbuf[fsk->N+fsk->Ts*2]; /* max nin value with timing slips */
/* complex unsigned 8 bit to float conversion */
for(i=0;i<fsk_nin(fsk);i++){
modbuf[i].real = ((float)pout[2*i]-127.0)/128.0;
modbuf[i].imag = ((float)pout[2*i+1]-127.0)/128.0;
}
pout += 2*fsk_nin(fsk);
nrawbuf -= 2*fsk_nin(fsk);
fsk_demod(fsk, bitbuf, modbuf);
if (fwrite(bitbuf, 1, fsk->Nbits, (FILE*)ctx) != (unsigned int)fsk->Nbits) {
fprintf(stderr, "Short write, bits lost, exiting!\n");
rtlsdr_cancel_async(dev);
}
}
/* copy left over to start of buffer */
memmove(rawbuf,pout,nrawbuf);
if (bytes_to_read > 0)
bytes_to_read -= len;
}
@ -120,7 +157,6 @@ int main(int argc, char **argv)
int dev_given = 0;
uint32_t frequency = 100000000;
uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
uint32_t out_block_size = DEFAULT_BUF_LENGTH;
while ((opt = getopt(argc, argv, "d:f:g:s:b:n:p:S")) != -1) {
switch (opt) {
@ -173,7 +209,9 @@ int main(int argc, char **argv)
}
buffer = malloc(out_block_size * sizeof(uint8_t));
rawbuf = malloc(2 * out_block_size * sizeof(uint8_t));
nrawbuf = 0;
if (!dev_given) {
dev_index = verbose_device_search("0");
}
@ -227,8 +265,20 @@ int main(int argc, char **argv)
goto out;
}
}
/* Reset endpoint before we start reading from it (mandatory) */
{
int Fs = DEFAULT_SAMPLE_RATE;
int Rs = 10000;
int M = 2;
int P = Fs/Rs;
fsk = fsk_create_hbr(Fs,Rs,M,P,FSK_DEFAULT_NSYM,FSK_NONE,100);
}
{
int fsk_lower = 0;
int fsk_upper = DEFAULT_SAMPLE_RATE/2;
fprintf(stderr,"Setting estimator limits to %d to %d Hz.\n", fsk_lower, fsk_upper);
fsk_set_freq_est_limits(fsk,fsk_lower,fsk_upper);
}
/* Reset endpoint before we start reading from it (mandatory) */
verbose_reset_buffer(dev);
if (sync_mode) {
@ -273,7 +323,9 @@ int main(int argc, char **argv)
fclose(file);
rtlsdr_close(dev);
fsk_destroy(fsk);
free (buffer);
free (rawbuf);
out:
return r >= 0 ? r : -r;
}