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B-Netz: Fixup of metering pulse

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This commit is contained in:
Andreas Eversberg
2017-10-16 13:48:39 -04:00
parent 2c4d0ee687
commit 5e14471eb6
3 changed files with 9 additions and 6 deletions
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7
src/bnetz/dsp.c
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@@ -47,7 +47,8 @@
#define MAX_MODULATION 3000.0
#define DBM0_DEVIATION 2800.0 /* deviation of dBm0 at 1 kHz */
#define TX_PEAK_FSK (4000.0 / 2000.0 * 1000.0 / DBM0_DEVIATION)
#define TX_PEAK_METER (3000.0 / 2900.0 * 1000.0 / DBM0_DEVIATION) /* FIXME: really 3KHz deviation??? */
#define TX_PEAK_METER (2000.0 / 2900.0 * 1000.0 / DBM0_DEVIATION) /* FIXME: what is the metering pulse deviation??? we use half of the 4kHz deviation, so we can still use -6dB of the speech level */
#define DAMPEN_METER 0.5 /* use -6dB to dampen speech while sending metering pulse (according to FTZ 1727 Pfl 32 Clause 3.2.6.6.5) */
#define MAX_DISPLAY 1.4 /* something above dBm0 */
#define BIT_RATE 100.0
#define BIT_ADJUST 0.5 /* full adjustment on bit change */
@@ -284,7 +285,9 @@ static void metering_tone(bnetz_t *bnetz, sample_t *samples, int length)
phase = bnetz->meter_phase65536;
for (i = 0; i < length; i++) {
*samples++ += dsp_metering[(uint16_t)phase];
/* Add metering pulse, also dampen audio level by 6 dB */
*samples = (*samples) * DAMPEN_METER + dsp_metering[(uint16_t)phase];
samples++;
phase += phaseshift;
if (phase >= 65536)
phase -= 65536;