diff options
Diffstat (limited to 'src/cnetz/scrambler.c')
| -rw-r--r-- | src/cnetz/scrambler.c | 22 |
1 files changed, 6 insertions, 16 deletions
diff --git a/src/cnetz/scrambler.c b/src/cnetz/scrambler.c index 2b49335..439e054 100644 --- a/src/cnetz/scrambler.c +++ b/src/cnetz/scrambler.c @@ -19,6 +19,7 @@ #include <stdint.h> #include <math.h> +#include "../common/sample.h" #include "scrambler.h" #define PI M_PI @@ -42,7 +43,8 @@ void scrambler_init(void) int i; for (i = 0; i < 256; i++) { - carrier[i] = sin((double)i / 256.0 * 2 * PI); + /* 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; } } @@ -56,10 +58,8 @@ void scrambler_setup(scrambler_t *scrambler, int samplerate) * Then we got spectrum above carrier and mirrored spectrum below carrier. * Afterwards we cut off carrier frequency and frequencies above carrier. */ -void scrambler(scrambler_t *scrambler, int16_t *samples, int length) +void scrambler(scrambler_t *scrambler, sample_t *samples, int length) { - double spl[length]; - int32_t sample; double phaseshift, phase; int i; @@ -68,7 +68,7 @@ void scrambler(scrambler_t *scrambler, int16_t *samples, int length) for (i = 0; i < length; i++) { /* modulate samples to carrier */ - spl[i] = (double)samples[i] / 32768.0 * carrier[((uint8_t)phase) & 0xff]; + samples[i] *= carrier[((uint8_t)phase) & 0xff]; phase += phaseshift; if (phase >= 256.0) phase -= 256.0; @@ -77,17 +77,7 @@ void scrambler(scrambler_t *scrambler, int16_t *samples, int length) scrambler->carrier_phase256 = phase; /* cut off carrier frequency and modulation above carrier frequency */ - filter_process(&scrambler->lp, spl, length); - - for (i = 0; i < length; i++) { - /* store result */ - sample = spl[i] * 2.0 * 32768.0; - if (sample > 32767) - sample = 32767; - else if (sample < -32768) - sample = -32768; - *samples++ = sample; - } + filter_process(&scrambler->lp, samples, length); } |