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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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38
src/cnetz/dsp.c
View File

@@ -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;

43
src/cnetz/fsk_fm_demod.c
View File

@@ -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

4
src/cnetz/fsk_fm_demod.h
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@@ -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;

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);

4
src/cnetz/scrambler.h
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@@ -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;

4
src/cnetz/telegramm.c
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@@ -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);