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osmocom-analog
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C-Netz: Correctly synchronize time stamp of SpK to OgK 

Even if the SpK is not used (yet), it must count time stamp (bit_time) so that
SpK keeps in sync with the OgK, until frames are received from mobile station.
This commit is contained in:
Andreas Eversberg 2019-10-26 11:40:48 +02:00
parent 6dd9999dc8
commit 195f7481d8
3 changed files with 53 additions and 48 deletions
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9
src/cnetz/dsp.c
View File

@ -564,8 +564,9 @@ void sender_receive(sender_t *sender, sample_t *samples, int length, double __at
if (cnetz->dsp_mode != DSP_MODE_OFF) {
iir_process(&cnetz->lp, samples, length);
fsk_fm_demod(&cnetz->fsk_demod, samples, length);
}
fsk_fm_demod(&cnetz->fsk_demod, samples, length); /* process */
} else
fsk_fm_demod(&cnetz->fsk_demod, NULL, length); /* just count bit time */
return;
}
@ -610,7 +611,7 @@ again:
/* start new telegramm, so we generate one */
if (pos == 0) {
/* a new hyper frame starts */
/* a new super frame starts */
if (cnetz->sched_ts == 0 && cnetz->sched_r_m == 0) {
/* measure actual signal speed */
calc_clock_speed(cnetz, (double)cnetz->sender.samplerate * 2.4, 1, 1);
@ -624,7 +625,7 @@ again:
cnetz_t *master = (cnetz_t *)cnetz->sender.master;
/* it may happen that the sample count does not match with the master,
* because one has a phase wrap before and the other after a sample.
* then we do it next hyper frame cycle */
* then we do it next super frame cycle */
if (master->frame_last_scount == cnetz->fsk_tx_scount) {
PDEBUG(DDSP, DEBUG_DEBUG, "Sync phase of slave to master: master=%.15f, slave=%.15f, diff=%.15f\n", master->frame_last_phase, cnetz->fsk_tx_phase, master->frame_last_phase - cnetz->fsk_tx_phase);
cnetz->fsk_tx_phase = master->frame_last_phase;

6
src/cnetz/fsk_demod.c
View File

@ -584,6 +584,8 @@ void fsk_fm_demod(fsk_fm_demod_t *fsk, sample_t *samples, int length)
/* process signaling block, sample by sample */
for (i = 0; i < length; i++) {
/* samples == NULL, if no processing is wanted, then just count bit time */
if (samples) {
fsk->bit_buffer_spl[fsk->bit_buffer_pos++] = samples[i];
if (fsk->bit_buffer_pos == fsk->bit_buffer_len)
fsk->bit_buffer_pos = 0;
@ -634,6 +636,7 @@ void fsk_fm_demod(fsk_fm_demod_t *fsk, sample_t *samples, int length)
}
}
}
fsk->bit_time += fsk->bits_per_sample;
if (fsk->bit_time >= BITS_PER_SUPERFRAME) {
fsk->bit_time -= BITS_PER_SUPERFRAME;
@ -652,10 +655,11 @@ void fsk_correct_sync(fsk_fm_demod_t *fsk, double offset)
fsk->bit_time = fmod(fsk->bit_time - offset + BITS_PER_SUPERFRAME, BITS_PER_SUPERFRAME);
}
/* copy sync from one instance to another (used to sync RX of SpK to OgK */
/* copy sync from one instance to another (used to sync RX of SpK to OgK) */
void fsk_copy_sync(fsk_fm_demod_t *fsk_to, fsk_fm_demod_t *fsk_from)
{
fsk_to->bit_time = fsk_from->bit_time;
fsk_demod_reset(fsk_to);
}
void fsk_demod_reset(fsk_fm_demod_t *fsk)

2
src/cnetz/main.c
View File

@ -526,7 +526,7 @@ int main(int argc, char *argv[])
/* OgK must be the first channel, so it becomes master. This is required for syncing SPK channels */
if (i != 0) {
fprintf(stderr, "The first channel you defined must be OgK (control) or OgK/SPK (control/speech) channel type. Quitting!\n");
fprintf(stderr, "The first channel you define must be OgK (control) or OgK/SPK (control/speech) channel type. Quitting!\n");
goto fail;
}