Restructure: Move scrambler from C-Netz code to 'libscrambler'

1 files changed, 0 insertions, 83 deletions

diff --git a/src/cnetz/scrambler.c b/src/cnetz/scrambler.c
deleted file mode 100644
index ad57b08..0000000
--- a/src/cnetz/scrambler.c
+++ /dev/null
@@ -1,83 +0,0 @@
-/* C-Netz audio spectrum inversion (Sprachverschleierung)
- *
- * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
- * All Rights Reserved
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <stdint.h>
-#include <math.h>
-#include "../common/sample.h"
-#include "scrambler.h"
-
-#define PI		M_PI
-
-/* FTZ 171 TR 60 Clause 6.2
- * Carrier frequency, that is the spectrum that is mirrored */
-#define CARRIER_HZ	3300.0
-#define FILTER_BELOW	300.0
-#define FILTER_TURNS	2
-
-/* FTZ 171 TR 60 Clause 6.3
- * How much must the carrier frequency be lower than a 1000 HZ tone that passes the inversion.
- * The filter must be tuned to get that loss. */
-#define TEST_1000HZ_DB	55.0
-
-/* sine wave for carrier to modulate to */
-static double carrier[65536];
-
-void scrambler_init(void)
-{
-	int 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 / 65536.0 * 2 * PI) * 2.0;
-	}
-}
-
-void scrambler_setup(scrambler_t *scrambler, int samplerate)
-{
-	iir_lowpass_init(&scrambler->lp, CARRIER_HZ - FILTER_BELOW, samplerate, FILTER_TURNS);
-	scrambler->carrier_phaseshift65536 = 65536.0 / ((double)samplerate / CARRIER_HZ);
-}
-
-/* Modulate samples to carriere that is twice the mirror frequency.
- * 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, sample_t *samples, int length)
-{
-	double phaseshift, phase;
-	int i;
-
-	phaseshift = scrambler->carrier_phaseshift65536;
-	phase = scrambler->carrier_phase65536;
-
-	for (i = 0; i < length; i++) {
-		/* modulate samples to carrier */
-		samples[i] *= carrier[(uint16_t)phase];
-		phase += phaseshift;
-		if (phase >= 65536.0)
-			phase -= 65536.0;
-	}
-
-	scrambler->carrier_phase65536 = phase;
-
-	/* cut off carrier frequency and modulation above carrier frequency */
-	iir_process(&scrambler->lp, samples, length);
-}
-
-