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minimodem: rx rate measurement

This commit is contained in:
Kamal Mostafa 2011-06-21 12:18:33 -07:00
parent 9002cf2694
commit 1ab9d2783c
1 changed files with 47 additions and 15 deletions
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62
src/minimodem.c
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@ -88,7 +88,6 @@ static void fsk_transmit_stdin(
while ( (c = getchar()) != EOF )
{
// HACK - baudot
unsigned int nwords;
unsigned int bits[2];
nwords = framebits_encoder(bits, c);
@ -112,6 +111,29 @@ static void fsk_transmit_stdin(
}
static void
report_no_carrier( fsk_plan *fskp,
unsigned int sample_rate,
float bfsk_data_rate,
unsigned int nframes_decoded,
size_t carrier_nsamples,
float confidence_total )
{
unsigned long long nbits_total = nframes_decoded * (fskp->n_data_bits+2);
float throughput_rate = nbits_total * sample_rate / (float)carrier_nsamples;
float throughput_skew = (throughput_rate - bfsk_data_rate)
/ bfsk_data_rate;
fprintf(stderr, "### NOCARRIER ndata=%u confidence=%.2f throughput=%.2f (%.1f%% %s) ###\n",
nframes_decoded,
confidence_total / nframes_decoded,
throughput_rate,
fabs(throughput_skew) * 100.0,
signbit(throughput_skew) ? "slow" : "fast"
);
}
void
usage()
{
@ -397,13 +419,18 @@ main( int argc, char*argv[] )
int carrier = 0;
float confidence_total = 0;
unsigned int nframes_decoded = 0;
size_t carrier_nsamples = 0;
unsigned int noconfidence = 0;
size_t noconfidence_nsamples = 0;
unsigned int advance = 0;
while ( 1 ) {
debug_log("advance=%u\n", advance);
if ( carrier && nframes_decoded > 0 )
carrier_nsamples += advance;
/* Shift the samples in samplebuf by 'advance' samples */
assert( advance <= samplebuf_size );
@ -519,29 +546,31 @@ main( int argc, char*argv[] )
#define FSK_MAX_NOCONFIDENCE_BITS 20
if ( confidence <= FSK_MIN_CONFIDENCE ) {
// FIXME: explain
if ( ++noconfidence > FSK_MAX_NOCONFIDENCE_BITS )
{
// FIXME: explain
if ( ++noconfidence > FSK_MAX_NOCONFIDENCE_BITS )
{
#ifdef CARRIER_AUTODETECT_THRESHOLD
carrier_band = -1;
carrier_band = -1;
#endif
if ( carrier ) {
fprintf(stderr, "### NOCARRIER ndata=%u confidence=%.2f ###\n",
nframes_decoded, confidence_total / nframes_decoded );
carrier = 0;
confidence_total = 0;
nframes_decoded = 0;
}
if ( carrier ) {
carrier_nsamples -= noconfidence_nsamples;
report_no_carrier(fskp, sample_rate, bfsk_data_rate,
nframes_decoded, carrier_nsamples, confidence_total);
carrier = 0;
carrier_nsamples = 0;
confidence_total = 0;
nframes_decoded = 0;
}
}
/* Advance the sample stream forward by try_max_nsamples so the
* next time around the loop we continue searching from where
* we left off this time. */
advance = try_max_nsamples;
noconfidence_nsamples += advance;
continue;
}
if ( !carrier ) {
if ( bfsk_data_rate >= 100 )
fprintf(stderr, "### CARRIER %u @ %u Hz ###\n",
@ -555,9 +584,11 @@ main( int argc, char*argv[] )
bfsk_framebits_decode(0, 0, 0); /* reset the frame processor */
}
confidence_total += confidence;
nframes_decoded++;
noconfidence = 0;
noconfidence_nsamples = 0;
/* Advance the sample stream forward past the decoded frame
* but not past the stop bit, since we want it to appear as
@ -606,8 +637,9 @@ main( int argc, char*argv[] )
} /* end of the main loop */
if ( carrier ) {
fprintf(stderr, "### NOCARRIER ndata=%u confidence=%.2f ###\n",
nframes_decoded, confidence_total / nframes_decoded );
carrier_nsamples -= noconfidence_nsamples;
report_no_carrier(fskp, sample_rate, bfsk_data_rate,
nframes_decoded, carrier_nsamples, confidence_total);
}
simpleaudio_close(sa);