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A-Netz: Option to set gain of paging tones

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This commit is contained in:
Andreas Eversberg
2017-01-08 11:22:24 +01:00
parent d28467c125
commit bf0abd627d
6 changed files with 46 additions and 29 deletions
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38
src/anetz/dsp.c
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@@ -37,8 +37,6 @@
/* signaling */
#define BANDWIDTH 15000.0 /* maximum bandwidth */
#define TX_PEAK_TONE 8192.0 /* peak amplitude for all tones */
#warning FIXME: only with emphasis, use seperate option for volume, override by sdr
#define TX_PEAK_PAGE 32766.0 /* peak amplitude paging tone */
#define CHUNK_DURATION 0.010 /* 10 ms */
// FIXME: how long until we detect a tone?
@@ -56,7 +54,6 @@ static double fsk_tones[2] = {
/* table for fast sine generation */
int dsp_sine_tone[256];
int dsp_sine_page[256];
/* global init for audio processing */
void dsp_init(void)
@@ -68,22 +65,16 @@ void dsp_init(void)
for (i = 0; i < 256; i++) {
s = sin((double)i / 256.0 * 2.0 * PI);
dsp_sine_tone[i] = (int)(s * TX_PEAK_TONE);
s = cos((double)i / 256.0 * 2.0 * PI);
dsp_sine_page[i] = (int)(s * TX_PEAK_PAGE);
}
if (TX_PEAK_TONE > 32767.0) {
fprintf(stderr, "TX_PEAK_TONE definition too high, please fix!\n");
abort();
}
if (TX_PEAK_PAGE > 32767.0) {
fprintf(stderr, "TX_PEAK_PAGE definition too high, please fix!\n");
abort();
}
}
/* Init transceiver instance. */
int dsp_init_sender(anetz_t *anetz, int page_sequence)
int dsp_init_sender(anetz_t *anetz, double page_gain, int page_sequence)
{
int16_t *spl;
double coeff;
@@ -96,6 +87,11 @@ int dsp_init_sender(anetz_t *anetz, int page_sequence)
anetz->sender.bandwidth = BANDWIDTH;
anetz->sender.sample_deviation = 11000.0 / (double)TX_PEAK_TONE;
anetz->page_gain = page_gain;
if (page_gain * TX_PEAK_TONE > 32767.0) {
page_gain = 32767.0 / TX_PEAK_TONE;
PDEBUG_CHAN(DDSP, DEBUG_NOTICE, "Highest possible gain of paging tones is %.1f dB.\n", log10(page_gain) * 20);
}
anetz->page_sequence = page_sequence;
audio_init_loss(&anetz->sender.loss, LOSS_INTERVAL, anetz->sender.loss_volume, LOSS_TIME);
@@ -245,12 +241,12 @@ void dsp_set_paging(anetz_t *anetz, double *freq)
}
/* Generate audio stream of 4 simultanious paging tones. Keep phase for next call of function.
* Use TX_PEAK_PAGE for all tones, which gives peak of (TX_PEAK_PAGE / 4) for each individual tone. */
* Use TX_PEAK_TONE*page_gain for all tones, which gives peak of 1/4th for each individual tone. */
static void fsk_paging_tone(anetz_t *anetz, int16_t *samples, int length)
{
double phaseshift[4], phase[4];
int i;
int32_t sample;
double sample;
for (i = 0; i < 4; i++) {
phaseshift[i] = anetz->paging_phaseshift256[i];
@@ -258,11 +254,11 @@ static void fsk_paging_tone(anetz_t *anetz, int16_t *samples, int length)
}
for (i = 0; i < length; i++) {
sample = (int32_t)dsp_sine_page[((uint8_t)phase[0]) & 0xff]
+ (int32_t)dsp_sine_page[((uint8_t)phase[1]) & 0xff]
+ (int32_t)dsp_sine_page[((uint8_t)phase[2]) & 0xff]
+ (int32_t)dsp_sine_page[((uint8_t)phase[3]) & 0xff];
*samples++ = sample >> 2;
sample = (int32_t)dsp_sine_tone[((uint8_t)phase[0]) & 0xff]
+ (int32_t)dsp_sine_tone[((uint8_t)phase[1]) & 0xff]
+ (int32_t)dsp_sine_tone[((uint8_t)phase[2]) & 0xff]
+ (int32_t)dsp_sine_tone[((uint8_t)phase[3]) & 0xff];
*samples++ = sample / 4.0 * anetz->page_gain;
phase[0] += phaseshift[0];
phase[1] += phaseshift[1];
phase[2] += phaseshift[2];
@@ -281,7 +277,7 @@ static void fsk_paging_tone(anetz_t *anetz, int16_t *samples, int length)
/* Generate audio stream of 4 sequenced paging tones. Keep phase for next call
* of function.
*
* Use TX_PEAK_PAGE / 2 for each tone, that is twice as much peak per tone.
* Use TX_PEAK_PAGE for each tone, that is four times higher per tone.
*
* Click removal when changing tones that have individual phase:
* When tone changes to next tone, a transition of 2ms is performed. The last
@@ -304,12 +300,12 @@ static void fsk_paging_tone_sequence(anetz_t *anetz, int16_t *samples, int lengt
while (length) {
/* use tone, but during transition of tones, keep phase 0 degrees (high level) until next tone reaches 0 degrees (high level) */
if (!transition)
*samples++ = dsp_sine_page[((uint8_t)phase[tone]) & 0xff] >> 1;
*samples++ = dsp_sine_tone[((uint8_t)phase[tone]) & 0xff] * anetz->page_gain;
else {
/* fade between old an new tone */
*samples++
= (double)dsp_sine_page[((uint8_t)phase[(tone - 1) & 3]) & 0xff] * (double)(transition - count) / (double)transition / 2.0
+ (double)dsp_sine_page[((uint8_t)phase[tone]) & 0xff] * (double)count / (double)transition / 2.0;
= (double)dsp_sine_tone[((uint8_t)phase[(tone - 1) & 3]) & 0xff] * (double)(transition - count) / (double)transition / 2.0 * anetz->page_gain
+ (double)dsp_sine_tone[((uint8_t)phase[tone]) & 0xff] * (double)count / (double)transition / 2.0 * anetz->page_gain;
}
phase[0] += phaseshift[0];
phase[1] += phaseshift[1];