Correcting all levels and move all remaining integer samples to sample_t

The leves are based on the standards of each mobile network. They
are adjusted to the specified frequency deviation now.

6 files changed, 58 insertions, 55 deletions

diff --git a/src/cnetz/dsp.c b/src/cnetz/dsp.c
index a927c55..1fc404a 100644
--- a/src/cnetz/dsp.c
+++ b/src/cnetz/dsp.c
@@ -43,9 +43,12 @@ extern int voice_deviation;
 
 #define PI		M_PI
 
-#define BANDWIDTH	5500.0	/* maximum bandwidth */
-#define FSK_DEVIATION	10000
-#define COMPANDOR_0DB	30000
+#define MAX_DEVIATION	4000.0
+#define MAX_MODULATION	5280.0
+#define DBM0_DEVIATION	4000.0	/* deviation of dBm0 at 1 kHz */
+#define COMPANDOR_0DB	1.0	/* A level of 0dBm (1.0) shall be unaccected */
+#define FSK_DEVIATION	(2500.0 / DBM0_DEVIATION) /* no emphasis */
+#define MAX_DISPLAY	1.4	/* something above dBm0, no emphasis */
 #define BITRATE		5280.0	/* bits per second */
 #define BLOCK_BITS	198	/* duration of one time slot including pause at beginning and end */
 #define CUT_OFF_OFFSET	300.0	/* cut off frequency for offset filter (level correction between subsequent audio chunks) */
@@ -76,7 +79,7 @@ static void dsp_init_ramp(cnetz_t *cnetz)
 			c = -sqrt(-c);
 		else
 			c = sqrt(c);
-		ramp_down[i] = (int)(c * (double)cnetz->fsk_deviation);
+		ramp_down[i] = c * (double)cnetz->fsk_deviation;
 		ramp_up[i] = -ramp_down[i];
 	}
 }
@@ -90,9 +93,8 @@ int dsp_init_sender(cnetz_t *cnetz, int measure_speed, double clock_speed[2], do
 
 	PDEBUG_CHAN(DDSP, DEBUG_DEBUG, "Init FSK for 'Sender'.\n");
 
-	/* set deviation and modulation parameters */
-	cnetz->sender.bandwidth = BANDWIDTH;
-	cnetz->sender.sample_deviation = 2500.0 / (double)FSK_DEVIATION;
+	/* set modulation parameters */
+	sender_set_fm(&cnetz->sender, MAX_DEVIATION, MAX_MODULATION, DBM0_DEVIATION, MAX_DISPLAY);
 
 	if (measure_speed) {
 		cnetz->measure_speed = measure_speed;
@@ -119,7 +121,7 @@ int dsp_init_sender(cnetz_t *cnetz, int measure_speed, double clock_speed[2], do
 	}
 
 	/* create devation and ramp */
-	cnetz->fsk_deviation = FSK_DEVIATION; /* be sure not to overflow -32767 .. 32767 */
+	cnetz->fsk_deviation = FSK_DEVIATION;
 	dsp_init_ramp(cnetz);
 	cnetz->fsk_noise = noise;
 
@@ -465,7 +467,7 @@ static int fsk_distributed_encode(cnetz_t *cnetz, const char *bits)
 			} while (phase < 256.0);
 			phase -= 256.0;
 		}
-		*marker = -32768; /* indicator for inserting speech */
+		*marker = 999; /* marker for inserting speech */
 	}
 	/* add 46 * (1+4+1 + 60) bits */
 	for (i = 0; i < 46; i++) {
@@ -556,7 +558,7 @@ static int fsk_distributed_encode(cnetz_t *cnetz, const char *bits)
 			} while (phase < 256.0);
 			phase -= 256.0;
 		}
-		*marker = -32768; /* indicator for inserting speech */
+		*marker = 999; /* marker for inserting speech */
 	}
 
 	/* depending on the number of samples, return the number */
@@ -706,7 +708,7 @@ again:
 	if (length - count < copy)
 		copy = length - count;
 	for (i = 0; i < copy; i++) {
-		if (*spl == -32768) {
+		if (*spl == 999) {
 			/* marker found to insert new chunk of audio */
 			jitter_load(&cnetz->sender.dejitter, speech_buffer, 100);
 			/* 1. compress dynamics */
@@ -722,15 +724,9 @@ again:
 				pre_emphasis(&cnetz->estate, speech_buffer, speech_length);
 			/* change level */
 			if (voice_deviation != 1) {
-				int sample, j;
-				for (j = 0; j < speech_length; j++) {
-					sample = speech_buffer[j] * voice_deviation;
-					if (sample > 32767)
-						sample = 32767;
-					if (sample < -32768)
-						sample = -32768;
-					speech_buffer[j] = sample;
-				}
+				int j;
+				for (j = 0; j < speech_length; j++)
+					speech_buffer[j] *= (double)voice_deviation;
 			}
 			speech_pos = 0;
 		}
@@ -801,7 +797,7 @@ void unshrink_speech(cnetz_t *cnetz, sample_t *speech_buffer, int count)
 	factor = cnetz->offset_factor;
 	for (i = 0; i < count; i++) {
 		/* change level */
-		x = speech_buffer[i] / voice_deviation;
+		x = speech_buffer[i] / (double)voice_deviation;
 		/* high-pass to remove low level frequencies, caused by level jump between audio chunks */
 		y = factor * (y_last + x - x_last);
 		x_last = x;
diff --git a/src/cnetz/fsk_fm_demod.c b/src/cnetz/fsk_fm_demod.c
index 74dd8ab..c151fb7 100644
--- a/src/cnetz/fsk_fm_demod.c
+++ b/src/cnetz/fsk_fm_demod.c
@@ -148,7 +148,7 @@ int fsk_fm_init(fsk_fm_demod_t *fsk, cnetz_t *cnetz, int samplerate, double bitr
 		goto error;
 	}
 
-	fsk->level_threshold = 655;
+	fsk->level_threshold = 0.1;
 
 	return 0;
 
@@ -170,9 +170,10 @@ void fsk_fm_exit(fsk_fm_demod_t *fsk)
 }
 
 /* get levels, sync time and jitter from sync sequence or frame data */
-static inline void get_levels(fsk_fm_demod_t *fsk, int *_min, int *_max, int *_avg, int *_probes, int num, double *_time, double *_jitter)
+static inline void get_levels(fsk_fm_demod_t *fsk, double *_min, double *_max, double *_avg, int *_probes, int num, double *_time, double *_jitter)
 {
-	int min = 32767, max = -32768, avg = 0, count = 0, level;
+	int count = 0;
+	double min = 0, max = 0, avg = 0, level;
 	double time = 0, t, sync_average, sync_time, jitter = 0;
 	int bit_offset;
 	int i;
@@ -192,19 +193,20 @@ static inline void get_levels(fsk_fm_demod_t *fsk, int *_min, int *_max, int *_a
 		if (t > BITS_PER_SUPERFRAME / 2)
 			t -= BITS_PER_SUPERFRAME;
 //if (fsk->cnetz->dsp_mode == DSP_MODE_SPK_V)
-//	printf("%d: level=%d%% @%.2f difference=%.2f\n", bit_offset, level * 100 / 65536, fsk->change_when[(fsk->change_pos - 1 - i) & 0xff], t);
+//	printf("%d: level=%.0f%% @%.2f difference=%.2f\n", bit_offset, level * 100, fsk->change_when[(fsk->change_pos - 1 - i) & 0xff], t);
 		time += t;
 
-		if (level < min)
+		if (i == 0 || level < min)
 			min = level;
-		if (level > max)
+		if (i == 0 || level > max)
 			max = level;
 		avg += level;
 		count++;
 	}
 
+	/* should never happen */
 	if (!count) {
-		*_min = *_max = *_avg = 0;
+		*_min = *_max = *_avg = 0.0;
 		return;
 	}
 
@@ -219,7 +221,7 @@ static inline void get_levels(fsk_fm_demod_t *fsk, int *_min, int *_max, int *_a
 	*_probes = count;
 	*_min = min;
 	*_max = max;
-	*_avg = avg / count;
+	*_avg = avg / (double)count;
 
 	if (_time) {
 //		if (fsk->cnetz->dsp_mode == DSP_MODE_SPK_V)
@@ -254,15 +256,16 @@ static inline void get_levels(fsk_fm_demod_t *fsk, int *_min, int *_max, int *_a
 	}
 }
 
-static inline void got_bit(fsk_fm_demod_t *fsk, int bit, int change_level)
+static inline void got_bit(fsk_fm_demod_t *fsk, int bit, double change_level)
 {
-	int min, max, avg, probes;
+	int probes;
+	double min, max, avg;
 
 	/* count bits, but do not exceed 4 bits per SPK block */
 	if (fsk->cnetz->dsp_mode == DSP_MODE_SPK_V) {
 		/* for first bit, we have only half of the modulation deviation, so we multiply level by two */
 		if (fsk->bit_count == 0)
-			change_level *= 2;
+			change_level *= 2.0;
 		if (fsk->bit_count == 4)
 			return;
 	}
@@ -284,20 +287,20 @@ static inline void got_bit(fsk_fm_demod_t *fsk, int bit, int change_level)
 		 * for all other bits in the sync sequence.
 		 * after sync, the theshold is set to half of the average of
 		 * all changes in the sync sequence */
-		if (change_level) {
-			fsk->level_threshold = (double)change_level / 2.0;
+		if (change_level > 0.0) {
+			fsk->level_threshold = change_level / 2.0;
 		} else if ((fsk->rx_sync & 0x1f) == 0x00 || (fsk->rx_sync & 0x1f) == 0x1f) {
 			if (fsk->cnetz->dsp_mode != DSP_MODE_SPK_V)
-				fsk->level_threshold = 655;
+				fsk->level_threshold = 0.01;
 		}
 		if (detect_sync(fsk->rx_sync)) {
 			fsk->sync = FSK_SYNC_POSITIVE;
 got_sync:
 			get_levels(fsk, &min, &max, &avg, &probes, 30, &fsk->sync_time, &fsk->sync_jitter);
-			fsk->sync_level = (double)avg / 65535.0;
+			fsk->sync_level = avg / 2.0;
 			if (fsk->sync == FSK_SYNC_NEGATIVE)
 				fsk->sync_level = -fsk->sync_level;
-//			printf("sync (change min=%d%% max=%d%% avg=%d%% sync_time=%.2f jitter=%.2f probes=%d)\n", min * 100 / 65535, max * 100 / 65535, avg * 100 / 65535, fsk->sync_time, fsk->sync_jitter, probes);
+//			printf("sync (change min=%.0f%% max=%.0f%% avg=%.0f%% sync_time=%.2f jitter=%.2f probes=%d)\n", min * 100, max * 100, avg * 100, fsk->sync_time, fsk->sync_jitter, probes);
 			fsk->level_threshold = (double)avg / 2.0;
 			fsk->rx_sync = 0;
 			fsk->rx_buffer_count = 0;
@@ -342,6 +345,10 @@ static inline void find_change(fsk_fm_demod_t *fsk)
 	change_at = -1;
 	change_positive = -1;
 
+	/* get level range (level_min and level_max) and also
+	 * get maximum slope (change_max) and where it was
+	 * (change_at) and what direction it went (change_positive)
+	 */
 	for (i = 0; i < fsk->bit_buffer_len; i++) {
 		last_s = s;
 		s = fsk->bit_buffer_spl[fsk->bit_buffer_pos++];
@@ -417,7 +424,7 @@ void fsk_fm_demod(fsk_fm_demod_t *fsk, sample_t *samples, int length)
 		if (fsk->cnetz->dsp_mode != DSP_MODE_SPK_V) {
 #ifdef DEBUG_DECODER
 			DEBUG_DECODER
-				puts(debug_amplitude(samples[i] / 32768.0));
+				puts(debug_amplitude(samples[i]));
 #endif
 			find_change(fsk);
 		} else {
@@ -441,7 +448,7 @@ void fsk_fm_demod(fsk_fm_demod_t *fsk, sample_t *samples, int length)
 			if (t >= 0.5 && t < 5.5) {
 #ifdef DEBUG_DECODER
 				DEBUG_DECODER
-					puts(debug_amplitude(samples[i] / 32768.0));
+					puts(debug_amplitude(samples[i]));
 #endif
 				find_change(fsk);
 			} else
diff --git a/src/cnetz/fsk_fm_demod.h b/src/cnetz/fsk_fm_demod.h
index bf782e5..c8692c3 100644
--- a/src/cnetz/fsk_fm_demod.h
+++ b/src/cnetz/fsk_fm_demod.h
@@ -24,7 +24,7 @@ typedef struct fsk_fm_demod {
 	int		bit_buffer_len;		/* number of samples in ring buffer */
 	int		bit_buffer_half;	/* half of ring buffer */
 	int		bit_buffer_pos;		/* current position to write next sample */
-	int		level_threshold;	/* threshold for detection of next level change */
+	double		level_threshold;	/* threshold for detection of next level change */
 	double		bits_per_sample;	/* duration of one sample in bits */
 	double		next_bit;		/* count time to detect bits */
 	int		bit_count;		/* counts bits, to match 4 bits at distributed signaling */
@@ -45,7 +45,7 @@ typedef struct fsk_fm_demod {
 	int		rx_buffer_count;	/* counter when receiving bits */
 
 	/* statistics */
-	int		change_levels[256];	/* ring buffer to store levels */
+	double		change_levels[256];	/* ring buffer to store levels */
 	double		change_when[256];	/* ring buffer to store time when level has changed */
 	uint8_t		change_pos;		/* index for next write */
 } fsk_fm_demod_t;
diff --git a/src/cnetz/scrambler.c b/src/cnetz/scrambler.c
index 439e054..f5adc03 100644
--- a/src/cnetz/scrambler.c
+++ b/src/cnetz/scrambler.c
@@ -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);
diff --git a/src/cnetz/scrambler.h b/src/cnetz/scrambler.h
index ffc2d77..19adba7 100644
--- a/src/cnetz/scrambler.h
+++ b/src/cnetz/scrambler.h
@@ -1,8 +1,8 @@
 #include "../common/filter.h"
 
 typedef struct scrambler {
-	double		carrier_phaseshift256;	/* carrier phase shift per sample */
-	double		carrier_phase256;	/* current phase of carrier frequency */
+	double		carrier_phaseshift65536;/* carrier phase shift per sample */
+	double		carrier_phase65536;	/* current phase of carrier frequency */
 	filter_t	lp;			/* filter to remove carrier frequency */
 } scrambler_t;
 
diff --git a/src/cnetz/telegramm.c b/src/cnetz/telegramm.c
index 8edbb2e..e3565eb 100644
--- a/src/cnetz/telegramm.c
+++ b/src/cnetz/telegramm.c
@@ -1492,9 +1492,9 @@ void cnetz_decode_telegramm(cnetz_t *cnetz, const char *bits, double level, doub
 	telegramm.jitter = jitter;
 
 	if (bit_errors)
-		PDEBUG_CHAN(DDSP, DEBUG_INFO, "RX Level: %.0f%% Jitter: %.2f Sync Time: %.2f (TS %.2f) Bit errors: %d %s\n", fabs(level) * 32767.0 / cnetz->fsk_deviation * 100.0, jitter, sync_time, sync_time / 396.0, bit_errors, (level < 0) ? "NEGATIVE (phone's mode)" : "POSITIVE (base station's mode)");
+		PDEBUG_CHAN(DDSP, DEBUG_INFO, "RX Level: %.0f%% Jitter: %.2f Sync Time: %.2f (TS %.2f) Bit errors: %d %s\n", fabs(level) / cnetz->fsk_deviation * 100.0, jitter, sync_time, sync_time / 396.0, bit_errors, (level < 0) ? "NEGATIVE (phone's mode)" : "POSITIVE (base station's mode)");
 	else
-		PDEBUG_CHAN(DDSP, DEBUG_INFO, "RX Level: %.0f%% Jitter: %.2f Sync Time: %.2f (TS %.2f) %s\n", fabs(level) * 32767.0 / cnetz->fsk_deviation * 100.0, jitter, sync_time, sync_time / 396.0, (level < 0) ? "NEGATIVE (phone's mode)" : "POSITIVE (base station's mode)");
+		PDEBUG_CHAN(DDSP, DEBUG_INFO, "RX Level: %.0f%% Jitter: %.2f Sync Time: %.2f (TS %.2f) %s\n", fabs(level) / cnetz->fsk_deviation * 100.0, jitter, sync_time, sync_time / 396.0, (level < 0) ? "NEGATIVE (phone's mode)" : "POSITIVE (base station's mode)");
 
 	if (cnetz->sender.loopback) {
 		PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm in loopback test mode (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);