williamp/osmocom-analog
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Correcting all levels and move all remaining integer samples to sample_t

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The leves are based on the standards of each mobile network. They
are adjusted to the specified frequency deviation now.
This commit is contained in:
Andreas Eversberg
2017-01-29 07:25:12 +01:00
parent bd7ccc5fa0
commit 7e45f556ce
38 changed files with 484 additions and 397 deletions
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20
src/cnetz/scrambler.c
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@@ -36,22 +36,22 @@
#define TEST_1000HZ_DB 55.0
/* sine wave for carrier to modulate to */
static double carrier[256];
static double carrier[65536];
void scrambler_init(void)
{
int i;
for (i = 0; i < 256; i++) {
for (i = 0; i < 65536; i++) {
/* our amplitude must be doubled, since we have one spectrum above and one below carrier */
carrier[i] = sin((double)i / 256.0 * 2 * PI) * 2.0;
carrier[i] = sin((double)i / 65536.0 * 2 * PI) * 2.0;
}
}
void scrambler_setup(scrambler_t *scrambler, int samplerate)
{
filter_lowpass_init(&scrambler->lp, CARRIER_HZ - FILTER_BELOW, samplerate, FILTER_TURNS);
scrambler->carrier_phaseshift256 = 256.0 / ((double)samplerate / CARRIER_HZ);
scrambler->carrier_phaseshift65536 = 65536.0 / ((double)samplerate / CARRIER_HZ);
}
/* Modulate samples to carriere that is twice the mirror frequency.
@@ -63,18 +63,18 @@ void scrambler(scrambler_t *scrambler, sample_t *samples, int length)
double phaseshift, phase;
int i;
phaseshift = scrambler->carrier_phaseshift256;
phase = scrambler->carrier_phase256;
phaseshift = scrambler->carrier_phaseshift65536;
phase = scrambler->carrier_phase65536;
for (i = 0; i < length; i++) {
/* modulate samples to carrier */
samples[i] *= carrier[((uint8_t)phase) & 0xff];
samples[i] *= carrier[(uint16_t)phase];
phase += phaseshift;
if (phase >= 256.0)
phase -= 256.0;
if (phase >= 65536.0)
phase -= 65536.0;
}
scrambler->carrier_phase256 = phase;
scrambler->carrier_phase65536 = phase;
/* cut off carrier frequency and modulation above carrier frequency */
filter_process(&scrambler->lp, samples, length);