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RS-tracker/demod/mod/demod_mod.c

1576 wiersze
44 KiB
C
Czysty Wina Historia

/*
* sync header: correlation/matched filter
* compile:
* gcc -c demod_mod.c
* speedup:
* gcc -O2 -c demod_mod.c
* or
* gcc -Ofast -c demod_mod.c
*
* author: zilog80
*/
/* ------------------------------------------------------------------------------------ */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "demod_mod.h"
#define FM_GAIN (0.8)
/* ------------------------------------------------------------------------------------ */
#ifndef EXT_FSK
static void raw_dft(dft_t *dft, float complex *Z) {
int s, l, l2, i, j, k;
float complex w1, w2, T;
j = 1;
for (i = 1; i < dft->N; i++) {
if (i < j) {
T = Z[j-1];
Z[j-1] = Z[i-1];
Z[i-1] = T;
}
k = dft->N/2;
while (k < j) {
j = j - k;
k = k/2;
}
j = j + k;
}
for (s = 0; s < dft->LOG2N; s++) {
l2 = 1 << s;
l = l2 << 1;
w1 = (float complex)1.0;
w2 = dft->ew[s]; // cexp(-I*M_PI/(float)l2)
for (j = 1; j <= l2; j++) {
for (i = j; i <= dft->N; i += l) {
k = i + l2;
T = Z[k-1] * w1;
Z[k-1] = Z[i-1] - T;
Z[i-1] = Z[i-1] + T;
}
w1 = w1 * w2;
}
}
}
static void cdft(dft_t *dft, float complex *z, float complex *Z) {
int i;
for (i = 0; i < dft->N; i++) Z[i] = z[i];
raw_dft(dft, Z);
}
static void rdft(dft_t *dft, float *x, float complex *Z) {
int i;
for (i = 0; i < dft->N; i++) Z[i] = (float complex)x[i];
raw_dft(dft, Z);
}
static void Nidft(dft_t *dft, float complex *Z, float complex *z) {
int i;
for (i = 0; i < dft->N; i++) z[i] = conj(Z[i]);
raw_dft(dft, z);
// idft():
// for (i = 0; i < dft->N; i++) z[i] = conj(z[i])/(float)dft->N; // hier: z reell
}
static float bin2freq0(dft_t *dft, int k) {
float fq = dft->sr * k / /*(float)*/dft->N;
if (fq >= dft->sr/2.0) fq -= dft->sr;
return fq;
}
static float bin2freq(dft_t *dft, int k) {
float fq = k / (float)dft->N;
if ( fq >= 0.5) fq -= 1.0;
return fq*dft->sr;
}
static float bin2fq(dft_t *dft, int k) {
float fq = k / (float)dft->N;
if ( fq >= 0.5) fq -= 1.0;
return fq;
}
static int max_bin(dft_t *dft, float complex *Z) {
int k, kmax;
double max;
max = 0; kmax = 0;
for (k = 0; k < dft->N; k++) {
if (cabs(Z[k]) > max) {
max = cabs(Z[k]);
kmax = k;
}
}
return kmax;
}
static int dft_window(dft_t *dft, int w) {
int n;
if (w < 0 || w > 3) return -1;
for (n = 0; n < dft->N2; n++) {
switch (w)
{
case 0: // (boxcar)
dft->win[n] = 1.0;
break;
case 1: // Hann
dft->win[n] = 0.5 * ( 1.0 - cos(2*M_PI*n/(float)(dft->N2-1)) );
break ;
case 2: // Hamming
dft->win[n] = 25/46.0 - (1.0 - 25/46.0)*cos(2*M_PI*n / (float)(dft->N2-1));
break ;
case 3: // Blackmann
dft->win[n] = 7938/18608.0
- 9240/18608.0*cos(2*M_PI*n / (float)(dft->N2-1))
+ 1430/18608.0*cos(4*M_PI*n / (float)(dft->N2-1));
break ;
}
}
while (n < dft->N) dft->win[n++] = 0.0;
return 0;
}
/* ------------------------------------------------------------------------------------ */
static int getCorrDFT(dsp_t *dsp) {
int i;
int mp = -1;
float mx = 0.0;
float mx2 = 0.0;
float re_cx = 0.0;
float xnorm = 1;
ui32_t mpos = 0;
ui32_t pos = dsp->sample_out;
double dc = 0.0;
int mp_ofs = 0;
float *sbuf = dsp->bufs;
dsp->mv = 0.0;
dsp->dc = 0.0;
if (dsp->K + dsp->L > dsp->DFT.N) return -1;
if (dsp->sample_out < dsp->L) return -2;
if (dsp->opt_iq > 1 && dsp->opt_dc) {
mp_ofs = (dsp->sps-1)/2;
sbuf = dsp->fm_buffer;
}
else {
sbuf = dsp->bufs;
}
for (i = 0; i < dsp->K + dsp->L; i++) (dsp->DFT).xn[i] = sbuf[(pos+dsp->M -(dsp->K + dsp->L-1) + i) % dsp->M];
while (i < dsp->DFT.N) (dsp->DFT).xn[i++] = 0.0;
rdft(&dsp->DFT, dsp->DFT.xn, dsp->DFT.X);
if (dsp->opt_dc) {
//X[0] = 0; // nicht ueber gesamte Laenge ... M10
//
// L < K ? // only last 2L samples (avoid M10 carrier offset)
dc = 0.0;
for (i = dsp->K - dsp->L; i < dsp->K + dsp->L; i++) dc += (dsp->DFT).xn[i];
dc /= 2.0*(float)dsp->L;
dsp->DFT.X[0] -= dsp->DFT.N * dc ;//* 0.95;
Nidft(&dsp->DFT, dsp->DFT.X, (dsp->DFT).cx);
for (i = 0; i < dsp->DFT.N; i++) (dsp->DFT).xn[i] = creal((dsp->DFT).cx[i])/(float)dsp->DFT.N;
}
for (i = 0; i < dsp->DFT.N; i++) dsp->DFT.Z[i] = dsp->DFT.X[i]*dsp->DFT.Fm[i];
Nidft(&dsp->DFT, dsp->DFT.Z, dsp->DFT.cx);
if (fabs(dc) < 0.5) dsp->dc = dc;
// relativ Peak - Normierung erst zum Schluss;
// dann jedoch nicht zwingend corr-Max wenn FM-Amplitude bzw. norm(x) nicht konstant
// (z.B. rs41 Signal-Pausen). Moeglicherweise wird dann wahres corr-Max in dem
// K-Fenster nicht erkannt, deshalb K nicht zu gross waehlen.
//
mx2 = 0.0; // t = L-1
for (i = dsp->L-1; i < dsp->K + dsp->L; i++) { // i=t .. i=t+K < t+1+K
re_cx = creal(dsp->DFT.cx[i]); // imag(cx)=0
if (re_cx*re_cx > mx2) {
mx = re_cx;
mx2 = mx*mx;
mp = i;
}
}
if (mp == dsp->L-1 || mp == dsp->K + dsp->L-1) return -4; // Randwert
// mp == t mp == K+t
mpos = pos - (dsp->K + dsp->L-1) + mp; // t = L-1
//xnorm = sqrt(dsp->qs[(mpos + 2*dsp->M) % dsp->M]); // Nvar = L
xnorm = 0.0;
for (i = 0; i < dsp->L; i++) xnorm += (dsp->DFT).xn[mp-i]*(dsp->DFT).xn[mp-i];
xnorm = sqrt(xnorm);
mx /= xnorm*(dsp->DFT).N;
if (dsp->opt_iq > 1 && dsp->opt_dc) mpos += mp_ofs;
dsp->mv = mx;
dsp->mv_pos = mpos;
if (pos == dsp->sample_out) dsp->buffered = dsp->sample_out - mpos;
// FM: s = gain * carg(w)/M_PI = gain * dphi / PI // gain=0.8
// FM audio gain? dc relative to FM-envelope?!
//
dsp->dDf = dsp->sr * dsp->dc / (2.0*FM_GAIN); // remaining freq offset
return mp;
}
/* ------------------------------------------------------------------------------------ */
static int findstr(char *buff, char *str, int pos) {
int i;
for (i = 0; i < 4; i++) {
if (buff[(pos+i)%4] != str[i]) break;
}
return i;
}
float read_wav_header(pcm_t *pcm, FILE *fp) {
char txt[4+1] = "\0\0\0\0";
unsigned char dat[4];
int byte, p=0;
int sample_rate = 0, bits_sample = 0, channels = 0;
if (fread(txt, 1, 4, fp) < 4) return -1;
if (strncmp(txt, "RIFF", 4)) return -1;
if (fread(txt, 1, 4, fp) < 4) return -1;
// pos_WAVE = 8L
if (fread(txt, 1, 4, fp) < 4) return -1;
if (strncmp(txt, "WAVE", 4)) return -1;
// pos_fmt = 12L
for ( ; ; ) {
if ( (byte=fgetc(fp)) == EOF ) return -1;
txt[p % 4] = byte;
p++; if (p==4) p=0;
if (findstr(txt, "fmt ", p) == 4) break;
}
if (fread(dat, 1, 4, fp) < 4) return -1;
if (fread(dat, 1, 2, fp) < 2) return -1;
if (fread(dat, 1, 2, fp) < 2) return -1;
channels = dat[0] + (dat[1] << 8);
if (fread(dat, 1, 4, fp) < 4) return -1;
memcpy(&sample_rate, dat, 4); //sample_rate = dat[0]|(dat[1]<<8)|(dat[2]<<16)|(dat[3]<<24);
if (fread(dat, 1, 4, fp) < 4) return -1;
if (fread(dat, 1, 2, fp) < 2) return -1;
//byte = dat[0] + (dat[1] << 8);
if (fread(dat, 1, 2, fp) < 2) return -1;
bits_sample = dat[0] + (dat[1] << 8);
// pos_dat = 36L + info
for ( ; ; ) {
if ( (byte=fgetc(fp)) == EOF ) return -1;
txt[p % 4] = byte;
p++; if (p==4) p=0;
if (findstr(txt, "data", p) == 4) break;
}
if (fread(dat, 1, 4, fp) < 4) return -1;
fprintf(stderr, "sample_rate: %d\n", sample_rate);
fprintf(stderr, "bits : %d\n", bits_sample);
fprintf(stderr, "channels : %d\n", channels);
if (pcm->sel_ch < 0 || pcm->sel_ch >= channels) pcm->sel_ch = 0; // default channel: 0
//fprintf(stderr, "channel-In : %d\n", pcm->sel_ch+1); // nur wenn nicht IQ
if (bits_sample != 8 && bits_sample != 16 && bits_sample != 32) return -1;
pcm->sr = sample_rate;
pcm->bps = bits_sample;
pcm->nch = channels;
return 0;
}
static int f32read_sample(dsp_t *dsp, float *s) {
int i;
unsigned int word = 0;
short *b = (short*)&word;
float *f = (float*)&word;
for (i = 0; i < dsp->nch; i++) {
if (fread( &word, dsp->bps/8, 1, dsp->fp) != 1) return EOF;
if (i == dsp->ch) { // i = 0: links bzw. mono
//if (bits_sample == 8) sint = b-128; // 8bit: 00..FF, centerpoint 0x80=128
//if (bits_sample == 16) sint = (short)b;
if (dsp->bps == 32) {
*s = *f;
}
else {
if (dsp->bps == 8) { *b -= 128; }
*s = *b/128.0;
if (dsp->bps == 16) { *s /= 256.0; }
}
}
}
return 0;
}
typedef struct {
double sumIQx;
double sumIQy;
float avgIQx;
float avgIQy;
ui32_t cnt;
ui32_t maxcnt;
ui32_t maxlim;
} iq_dc_t;
static iq_dc_t IQdc;
static int f32read_csample(dsp_t *dsp, float complex *z) {
float x, y;
if (dsp->bps == 32) { //float32
float f[2];
if (fread( f, dsp->bps/8, 2, dsp->fp) != 2) return EOF;
x = f[0];
y = f[1];
}
else if (dsp->bps == 16) { //int16
short b[2];
if (fread( b, dsp->bps/8, 2, dsp->fp) != 2) return EOF;
x = b[0]/32768.0;
y = b[1]/32768.0;
}
else { // dsp->bps == 8 //uint8
ui8_t u[2];
if (fread( u, dsp->bps/8, 2, dsp->fp) != 2) return EOF;
x = (u[0]-128)/128.0;
y = (u[1]-128)/128.0;
}
*z = (x - IQdc.avgIQx) + I*(y - IQdc.avgIQy);
IQdc.sumIQx += x;
IQdc.sumIQy += y;
IQdc.cnt += 1;
if (IQdc.cnt == IQdc.maxcnt) {
IQdc.avgIQx = IQdc.sumIQx/(float)IQdc.maxcnt;
IQdc.avgIQy = IQdc.sumIQy/(float)IQdc.maxcnt;
IQdc.sumIQx = 0; IQdc.sumIQy = 0; IQdc.cnt = 0;
if (IQdc.maxcnt < IQdc.maxlim) IQdc.maxcnt *= 2;
}
return 0;
}
static int f32read_cblock(dsp_t *dsp) {
int n;
int len;
float x, y;
len = dsp->decM;
if (dsp->bps == 8) { //uint8
ui8_t u[2*dsp->decM];
len = fread( u, dsp->bps/8, 2*dsp->decM, dsp->fp) / 2;
//for (n = 0; n < len; n++) dsp->decMbuf[n] = (u[2*n]-128)/128.0 + I*(u[2*n+1]-128)/128.0;
// u8: 0..255, 128 -> 0V
for (n = 0; n < len; n++) {
x = (u[2*n ]-128)/128.0;
y = (u[2*n+1]-128)/128.0;
dsp->decMbuf[n] = (x-IQdc.avgIQx) + I*(y-IQdc.avgIQy);
IQdc.sumIQx += x;
IQdc.sumIQy += y;
IQdc.cnt += 1;
if (IQdc.cnt == IQdc.maxcnt) {
IQdc.avgIQx = IQdc.sumIQx/(float)IQdc.maxcnt;
IQdc.avgIQy = IQdc.sumIQy/(float)IQdc.maxcnt;
IQdc.sumIQx = 0; IQdc.sumIQy = 0; IQdc.cnt = 0;
if (IQdc.maxcnt < IQdc.maxlim) IQdc.maxcnt *= 2;
}
}
}
else if (dsp->bps == 16) { //int16
short b[2*dsp->decM];
len = fread( b, dsp->bps/8, 2*dsp->decM, dsp->fp) / 2;
for (n = 0; n < len; n++) {
x = b[2*n ]/32768.0;
y = b[2*n+1]/32768.0;
dsp->decMbuf[n] = (x-IQdc.avgIQx) + I*(y-IQdc.avgIQy);
IQdc.sumIQx += x;
IQdc.sumIQy += y;
IQdc.cnt += 1;
if (IQdc.cnt == IQdc.maxcnt) {
IQdc.avgIQx = IQdc.sumIQx/(float)IQdc.maxcnt;
IQdc.avgIQy = IQdc.sumIQy/(float)IQdc.maxcnt;
IQdc.sumIQx = 0; IQdc.sumIQy = 0; IQdc.cnt = 0;
if (IQdc.maxcnt < IQdc.maxlim) IQdc.maxcnt *= 2;
}
}
}
else { // dsp->bps == 32 //float32
float f[2*dsp->decM];
len = fread( f, dsp->bps/8, 2*dsp->decM, dsp->fp) / 2;
for (n = 0; n < len; n++) {
x = f[2*n];
y = f[2*n+1];
dsp->decMbuf[n] = (x-IQdc.avgIQx) + I*(y-IQdc.avgIQy);
IQdc.sumIQx += x;
IQdc.sumIQy += y;
IQdc.cnt += 1;
if (IQdc.cnt == IQdc.maxcnt) {
IQdc.avgIQx = IQdc.sumIQx/(float)IQdc.maxcnt;
IQdc.avgIQy = IQdc.sumIQy/(float)IQdc.maxcnt;
IQdc.sumIQx = 0; IQdc.sumIQy = 0; IQdc.cnt = 0;
if (IQdc.maxcnt < IQdc.maxlim) IQdc.maxcnt *= 2;
}
}
}
return len;
}
/*
static int get_SNR_rs41(dsp_t *dsp) {
if (dsp->opt_iq)
// if(dsp->rs_typ == RS41)
{
if (dsp->sample_posnoise > 0) // rs41
{
if (dsp->sample_out >= dsp->sample_posframe && dsp->sample_out < dsp->sample_posframe+dsp->len_sq) {
if (dsp->sample_out == dsp->sample_posframe) dsp->V_signal = 0.0;
dsp->V_signal += cabs(dsp->rot_iqbuf[dsp->sample_out % dsp->N_IQBUF]);
}
if (dsp->sample_out == dsp->sample_posframe+dsp->len_sq) dsp->V_signal /= (double)dsp->len_sq;
if (dsp->sample_out >= dsp->sample_posnoise && dsp->sample_out < dsp->sample_posnoise+dsp->len_sq) {
if (dsp->sample_out == dsp->sample_posnoise) dsp->V_noise = 0.0;
dsp->V_noise += cabs(dsp->rot_iqbuf[dsp->sample_out % dsp->N_IQBUF]);
}
if (dsp->sample_out == dsp->sample_posnoise+dsp->len_sq) {
dsp->V_noise /= (double)dsp->len_sq;
if (dsp->V_signal > 0 && dsp->V_noise > 0) {
// iq-samples/V [-1..1]
// dBw = 2*dBv, P=c*U*U
// dBw = 2*10*log10(V/V0)
dsp->SNRdB = 20.0 * log10(dsp->V_signal/dsp->V_noise+1e-20);
}
}
}
}
else dsp->SNRdB = 0;
return 0;
}
*/
// decimate lowpass
static float *ws_dec;
static double sinc(double x) {
double y;
if (x == 0) y = 1;
else y = sin(M_PI*x)/(M_PI*x);
return y;
}
static int lowpass_init(float f, int taps, float **pws) {
double *h, *w;
double norm = 0;
int n;
float *ws = NULL;
if (taps % 2 == 0) taps++; // odd/symmetric
if ( taps < 1 ) taps = 1;
h = (double*)calloc( taps+1, sizeof(double)); if (h == NULL) return -1;
w = (double*)calloc( taps+1, sizeof(double)); if (w == NULL) return -1;
ws = (float*)calloc( 2*taps+1, sizeof(float)); if (ws == NULL) return -1;
for (n = 0; n < taps; n++) {
w[n] = 7938/18608.0 - 9240/18608.0*cos(2*M_PI*n/(taps-1)) + 1430/18608.0*cos(4*M_PI*n/(taps-1)); // Blackmann
h[n] = 2*f*sinc(2*f*(n-(taps-1)/2));
ws[n] = w[n]*h[n];
norm += ws[n]; // 1-norm
}
for (n = 0; n < taps; n++) {
ws[n] /= norm; // 1-norm
}
for (n = 0; n < taps; n++) ws[taps+n] = ws[n]; // duplicate/unwrap
*pws = ws;
free(h); h = NULL;
free(w); w = NULL;
return taps;
}
static int lowpass_update(float f, int taps, float *ws) {
double *h, *w;
double norm = 0;
int n;
if (taps % 2 == 0) taps++; // odd/symmetric
if ( taps < 1 ) taps = 1;
h = (double*)calloc( taps+1, sizeof(double)); if (h == NULL) return -1;
w = (double*)calloc( taps+1, sizeof(double)); if (w == NULL) return -1;
for (n = 0; n < taps; n++) {
w[n] = 7938/18608.0 - 9240/18608.0*cos(2*M_PI*n/(taps-1)) + 1430/18608.0*cos(4*M_PI*n/(taps-1)); // Blackmann
h[n] = 2*f*sinc(2*f*(n-(taps-1)/2));
ws[n] = w[n]*h[n];
norm += ws[n]; // 1-norm
}
for (n = 0; n < taps; n++) {
ws[n] /= norm; // 1-norm
}
for (n = 0; n < taps; n++) ws[taps+n] = ws[n];
free(h); h = NULL;
free(w); w = NULL;
return taps;
}
static float complex lowpass0(float complex buffer[], ui32_t sample, ui32_t taps, float *ws) {
ui32_t n;
double complex w = 0;
for (n = 0; n < taps; n++) {
w += buffer[(sample+n+1)%taps]*ws[taps-1-n];
}
return (float complex)w;
}
static float complex lowpass(float complex buffer[], ui32_t sample, ui32_t taps, float *ws) {
ui32_t n;
ui32_t s = sample % taps;
double complex w = 0;
for (n = 0; n < taps; n++) {
w += buffer[n]*ws[taps+s-n]; // ws[taps+s-n] = ws[(taps+sample-n)%taps]
}
return (float complex)w;
// symmetry: ws[n] == ws[taps-1-n]
}
static float re_lowpass0(float buffer[], ui32_t sample, ui32_t taps, float *ws) {
ui32_t n;
double w = 0;
for (n = 0; n < taps; n++) {
w += buffer[(sample+n+1)%taps]*ws[taps-1-n];
}
return (float)w;
}
static float re_lowpass(float buffer[], ui32_t sample, ui32_t taps, float *ws) {
ui32_t n;
ui32_t s = sample % taps;
double w = 0;
for (n = 0; n < taps; n++) {
w += buffer[n]*ws[taps+s-n]; // ws[taps+s-n] = ws[(taps+sample-n)%taps]
}
return (float)w;
}
int f32buf_sample(dsp_t *dsp, int inv) {
float s = 0.0;
float xneu, xalt;
float complex z, w, z0;
double gain = FM_GAIN;
double t = dsp->sample_in / (double)dsp->sr;
if (dsp->opt_iq) {
if (dsp->opt_iq == 5) {
ui32_t s_reset = dsp->dectaps*dsp->lut_len;
int j;
if ( f32read_cblock(dsp) < dsp->decM ) return EOF;
for (j = 0; j < dsp->decM; j++) {
dsp->decXbuffer[dsp->sample_dec % dsp->dectaps] = dsp->decMbuf[j] * dsp->ex[dsp->sample_dec % dsp->lut_len];
dsp->sample_dec += 1;
if (dsp->sample_dec == s_reset) dsp->sample_dec = 0;
}
z = lowpass(dsp->decXbuffer, dsp->sample_dec, dsp->dectaps, ws_dec);
}
else if ( f32read_csample(dsp, &z) == EOF ) return EOF;
z *= cexp(-t*2*M_PI*dsp->Df*I);
// IF-lowpass
if (dsp->opt_lp) {
dsp->lpIQ_buf[dsp->sample_in % dsp->lpIQtaps] = z;
z = lowpass(dsp->lpIQ_buf, dsp->sample_in, dsp->lpIQtaps, dsp->ws_lpIQ);
}
z0 = dsp->rot_iqbuf[(dsp->sample_in-1 + dsp->N_IQBUF) % dsp->N_IQBUF];
w = z * conj(z0);
s = gain * carg(w)/M_PI;
dsp->rot_iqbuf[dsp->sample_in % dsp->N_IQBUF] = z;
// FM-lowpass
if (dsp->opt_lp) {
dsp->lpFM_buf[dsp->sample_in % dsp->lpFMtaps] = s;
s = re_lowpass(dsp->lpFM_buf, dsp->sample_in, dsp->lpFMtaps, dsp->ws_lpFM);
}
dsp->fm_buffer[(dsp->sample_in - dsp->lpFMtaps/2 + dsp->M) % dsp->M] = s;
if (dsp->opt_iq >= 2)
{
double xbit = 0.0;
//float complex xi = cexp(+I*M_PI*dsp->h/dsp->sps);
double f1 = -dsp->h*dsp->sr/(2*dsp->sps);
double f2 = -f1;
float complex X0 = 0;
float complex X = 0;
int n = dsp->sps;
double tn = (dsp->sample_in-n) / (double)dsp->sr;
//t = dsp->sample_in / (double)dsp->sr;
//z = dsp->rot_iqbuf[dsp->sample_in % dsp->N_IQBUF];
z0 = dsp->rot_iqbuf[(dsp->sample_in-n + dsp->N_IQBUF) % dsp->N_IQBUF];
// f1
X0 = z0 * cexp(-tn*2*M_PI*f1*I); // alt
X = z * cexp(-t *2*M_PI*f1*I); // neu
dsp->F1sum += X - X0;
// f2
X0 = z0 * cexp(-tn*2*M_PI*f2*I); // alt
X = z * cexp(-t *2*M_PI*f2*I); // neu
dsp->F2sum += X - X0;
xbit = cabs(dsp->F2sum) - cabs(dsp->F1sum);
s = xbit / dsp->sps;
}
else if (0 && dsp->opt_iq >= 4)
{
double xbit = 0.0;
//float complex xi = cexp(+I*M_PI*dsp->h/dsp->sps);
double f1 = -dsp->h*dsp->sr/(2*dsp->sps);
double f2 = -f1;
float complex X1 = 0;
float complex X2 = 0;
int n = dsp->sps;
while (n > 0) {
n--;
t = -n / (double)dsp->sr;
z = dsp->rot_iqbuf[(dsp->sample_in - n + dsp->N_IQBUF) % dsp->N_IQBUF]; // +1
X1 += z*cexp(-t*2*M_PI*f1*I);
X2 += z*cexp(-t*2*M_PI*f2*I);
}
xbit = cabs(X2) - cabs(X1);
s = xbit / dsp->sps;
}
}
else {
if (f32read_sample(dsp, &s) == EOF) return EOF;
}
if (inv) s = -s;
dsp->bufs[dsp->sample_in % dsp->M] = s;
xneu = dsp->bufs[(dsp->sample_in ) % dsp->M];
xalt = dsp->bufs[(dsp->sample_in+dsp->M - dsp->Nvar) % dsp->M];
dsp->xsum += xneu - xalt; // + xneu - xalt
dsp->qsum += (xneu - xalt)*(xneu + xalt); // + xneu*xneu - xalt*xalt
dsp->xs[dsp->sample_in % dsp->M] = dsp->xsum;
dsp->qs[dsp->sample_in % dsp->M] = dsp->qsum;
dsp->sample_out = dsp->sample_in - dsp->delay;
dsp->sample_in += 1;
return 0;
}
static int read_bufbit(dsp_t *dsp, int symlen, char *bits, ui32_t mvp, int pos) {
// symlen==2: manchester2 0->10,1->01->1: 2.bit
double rbitgrenze = pos*symlen*dsp->sps;
ui32_t rcount = ceil(rbitgrenze);//+0.99; // dfm?
double sum = 0.0;
// bei symlen=2 (Manchester) kein dc noetig: -dc+dc=0 ;
// allerdings M10-header mit symlen=1
rbitgrenze += dsp->sps;
do {
sum += dsp->bufs[(rcount + mvp + dsp->M) % dsp->M] - dsp->dc;
rcount++;
} while (rcount < rbitgrenze); // n < dsp->sps
if (symlen == 2) {
rbitgrenze += dsp->sps;
do {
sum -= dsp->bufs[(rcount + mvp + dsp->M) % dsp->M] - dsp->dc;
rcount++;
} while (rcount < rbitgrenze); // n < dsp->sps
}
if (symlen != 2) {
if (sum >= 0) *bits = '1';
else *bits = '0';
}
else {
if (sum >= 0) strncpy(bits, "10", 2);
else strncpy(bits, "01", 2);
}
return 0;
}
static int headcmp(dsp_t *dsp, int opt_dc) {
int errs = 0;
int pos;
int step = 1;
char sign = 0;
int len = dsp->hdrlen/dsp->symhd;
int inv = dsp->mv < 0;
if (opt_dc == 0 || dsp->opt_iq > 1) dsp->dc = 0; // reset? e.g. 2nd pass
if (dsp->symhd != 1) step = 2;
if (inv) sign=1;
for (pos = 0; pos < len; pos++) { // L = dsp->hdrlen * dsp->sps + 0.5;
//read_bufbit(dsp, dsp->symhd, dsp->rawbits+pos*step, mvp+1-(int)(len*dsp->sps), pos);
read_bufbit(dsp, dsp->symhd, dsp->rawbits+pos*step, dsp->mv_pos+1-dsp->L, pos);
}
dsp->rawbits[pos] = '\0';
while (len > 0) {
if ((dsp->rawbits[len-1]^sign) != dsp->hdr[len-1]) errs += 1;
len--;
}
return errs;
}
/* -------------------------------------------------------------------------- */
int read_slbit(dsp_t *dsp, int *bit, int inv, int ofs, int pos, float l, int spike) {
// symlen==2: manchester2 10->0,01->1: 2.bit
float sample;
float avg;
float ths = 0.5, scale = 0.27;
double sum = 0.0;
double mid;
//double l = 1.0;
double bg = pos*dsp->symlen*dsp->sps;
double dc = 0.0;
if (dsp->opt_dc && dsp->opt_iq < 2) dc = dsp->dc;
if (pos == 0) {
bg = 0;
dsp->sc = 0;
}
if (dsp->symlen == 2) {
mid = bg + (dsp->sps-1)/2.0;
bg += dsp->sps;
do {
if (dsp->buffered > 0) dsp->buffered -= 1;
else if (f32buf_sample(dsp, inv) == EOF) return EOF;
sample = dsp->bufs[(dsp->sample_out-dsp->buffered + ofs + dsp->M) % dsp->M];
if (spike && fabs(sample - avg) > ths) {
avg = 0.5*(dsp->bufs[(dsp->sample_out-dsp->buffered-1 + ofs + dsp->M) % dsp->M]
+dsp->bufs[(dsp->sample_out-dsp->buffered+1 + ofs + dsp->M) % dsp->M]);
sample = avg + scale*(sample - avg); // spikes
}
sample -= dc;
if (l < 0 || (mid-l < dsp->sc && dsp->sc < mid+l)) sum -= sample;
dsp->sc++;
} while (dsp->sc < bg); // n < dsp->sps
}
mid = bg + (dsp->sps-1)/2.0;
bg += dsp->sps;
do {
if (dsp->buffered > 0) dsp->buffered -= 1;
else if (f32buf_sample(dsp, inv) == EOF) return EOF;
sample = dsp->bufs[(dsp->sample_out-dsp->buffered + ofs + dsp->M) % dsp->M];
if (spike && fabs(sample - avg) > ths) {
avg = 0.5*(dsp->bufs[(dsp->sample_out-dsp->buffered-1 + ofs + dsp->M) % dsp->M]
+dsp->bufs[(dsp->sample_out-dsp->buffered+1 + ofs + dsp->M) % dsp->M]);
sample = avg + scale*(sample - avg); // spikes
}
sample -= dc;
if (l < 0 || (mid-l < dsp->sc && dsp->sc < mid+l)) sum += sample;
dsp->sc++;
} while (dsp->sc < bg); // n < dsp->sps
if (sum >= 0) *bit = 1;
else *bit = 0;
return 0;
}
int read_softbit(dsp_t *dsp, hsbit_t *shb, int inv, int ofs, int pos, float l, int spike) {
// symlen==2: manchester2 10->0,01->1: 2.bit
float sample;
float avg;
float ths = 0.5, scale = 0.27;
double sum = 0.0;
double mid;
//double l = 1.0;
double bg = pos*dsp->symlen*dsp->sps;
double dc = 0.0;
ui8_t bit = 0;
if (dsp->opt_dc && dsp->opt_iq < 2) dc = dsp->dc;
if (pos == 0) {
bg = 0;
dsp->sc = 0;
}
if (dsp->symlen == 2) {
mid = bg + (dsp->sps-1)/2.0;
bg += dsp->sps;
do {
if (dsp->buffered > 0) dsp->buffered -= 1;
else if (f32buf_sample(dsp, inv) == EOF) return EOF;
sample = dsp->bufs[(dsp->sample_out-dsp->buffered + ofs + dsp->M) % dsp->M];
if (spike && fabs(sample - avg) > ths) {
avg = 0.5*(dsp->bufs[(dsp->sample_out-dsp->buffered-1 + ofs + dsp->M) % dsp->M]
+dsp->bufs[(dsp->sample_out-dsp->buffered+1 + ofs + dsp->M) % dsp->M]);
sample = avg + scale*(sample - avg); // spikes
}
sample -= dc;
if (l < 0 || (mid-l < dsp->sc && dsp->sc < mid+l)) sum -= sample;
dsp->sc++;
} while (dsp->sc < bg); // n < dsp->sps
}
mid = bg + (dsp->sps-1)/2.0;
bg += dsp->sps;
do {
if (dsp->buffered > 0) dsp->buffered -= 1;
else if (f32buf_sample(dsp, inv) == EOF) return EOF;
sample = dsp->bufs[(dsp->sample_out-dsp->buffered + ofs + dsp->M) % dsp->M];
if (spike && fabs(sample - avg) > ths) {
avg = 0.5*(dsp->bufs[(dsp->sample_out-dsp->buffered-1 + ofs + dsp->M) % dsp->M]
+dsp->bufs[(dsp->sample_out-dsp->buffered+1 + ofs + dsp->M) % dsp->M]);
sample = avg + scale*(sample - avg); // spikes
}
sample -= dc;
if (l < 0 || (mid-l < dsp->sc && dsp->sc < mid+l)) sum += sample;
dsp->sc++;
} while (dsp->sc < bg); // n < dsp->sps
if (sum >= 0) bit = 1;
else bit = 0;
shb->hb = bit;
shb->sb = (float)sum;
return 0;
}
int read_softbit2p(dsp_t *dsp, hsbit_t *shb, int inv, int ofs, int pos, float l, int spike, hsbit_t *shb1) {
// symlen==2: manchester2 10->0,01->1: 2.bit
float sample, sample1;
float avg;
float ths = 0.5, scale = 0.27;
double sum = 0.0, sum1 = 0.0;
double mid;
//double l = 1.0;
double bg = pos*dsp->symlen*dsp->sps;
double dc = 0.0;
ui8_t bit = 0, bit1 = 0;
if (dsp->opt_dc && dsp->opt_iq < 2) dc = dsp->dc;
if (pos == 0) {
bg = 0;
dsp->sc = 0;
}
if (dsp->symlen == 2) {
mid = bg + (dsp->sps-1)/2.0;
bg += dsp->sps;
do {
if (dsp->buffered > 0) dsp->buffered -= 1;
else if (f32buf_sample(dsp, inv) == EOF) return EOF;
sample = dsp->bufs[(dsp->sample_out-dsp->buffered + ofs + dsp->M) % dsp->M];
sample1 = dsp->bufs[(dsp->sample_out-dsp->buffered + ofs-1 + dsp->M) % dsp->M];
if (spike && fabs(sample - avg) > ths) {
avg = 0.5*(dsp->bufs[(dsp->sample_out-dsp->buffered-1 + ofs + dsp->M) % dsp->M]
+dsp->bufs[(dsp->sample_out-dsp->buffered+1 + ofs + dsp->M) % dsp->M]);
sample = avg + scale*(sample - avg); // spikes
}
sample -= dc;
sample1 -= dc;
if (l < 0 || (mid-l < dsp->sc && dsp->sc < mid+l)) {
sum -= sample;
sum1 -= sample1;
}
dsp->sc++;
} while (dsp->sc < bg); // n < dsp->sps
}
mid = bg + (dsp->sps-1)/2.0;
bg += dsp->sps;
do {
if (dsp->buffered > 0) dsp->buffered -= 1;
else if (f32buf_sample(dsp, inv) == EOF) return EOF;
sample = dsp->bufs[(dsp->sample_out-dsp->buffered + ofs + dsp->M) % dsp->M];
sample1 = dsp->bufs[(dsp->sample_out-dsp->buffered + ofs-1 + dsp->M) % dsp->M];
if (spike && fabs(sample - avg) > ths) {
avg = 0.5*(dsp->bufs[(dsp->sample_out-dsp->buffered-1 + ofs + dsp->M) % dsp->M]
+dsp->bufs[(dsp->sample_out-dsp->buffered+1 + ofs + dsp->M) % dsp->M]);
sample = avg + scale*(sample - avg); // spikes
}
sample -= dc;
sample1 -= dc;
if (l < 0 || (mid-l < dsp->sc && dsp->sc < mid+l)) {
sum += sample;
sum1 += sample1;
}
dsp->sc++;
} while (dsp->sc < bg); // n < dsp->sps
if (sum >= 0) bit = 1;
else bit = 0;
shb->hb = bit;
shb->sb = (float)sum;
if (sum1 >= 0) bit1 = 1;
else bit1 = 0;
shb1->hb = bit1;
shb1->sb = (float)sum1;
return 0;
}
/* -------------------------------------------------------------------------- */
#define IF_SAMPLE_RATE 48000
#define IF_SAMPLE_RATE_MIN 32000
#define IF_TRANSITION_BW (4e3) // 4kHz transition width
#define FM_TRANSITION_BW (2e3) // 2kHz transition width
#define SQRT2 1.4142135624 // sqrt(2)
// sigma = sqrt(log(2)) / (2*PI*BT):
//#define SIGMA 0.2650103635 // BT=0.5: 0.2650103635 , BT=0.3: 0.4416839392
// Gaussian FM-pulse
static double Q(double x) {
return 0.5 - 0.5*erf(x/SQRT2);
}
static double pulse(double t, double sigma) {
return Q((t-0.5)/sigma) - Q((t+0.5)/sigma);
}
static double norm2_vect(float *vect, int n) {
int i;
double x, y = 0.0;
for (i = 0; i < n; i++) {
x = vect[i];
y += x*x;
}
return y;
}
int init_buffers(dsp_t *dsp) {
int i, pos;
float b0, b1, b2, b, t;
float normMatch;
double sigma = sqrt(log(2)) / (2*M_PI*dsp->BT);
int p2 = 1;
int K, L, M;
int n, k;
float *m = NULL;
if (dsp->opt_iq == 5)
{
int IF_sr = IF_SAMPLE_RATE; // designated IF sample rate
int decM = 1; // decimate M:1
int sr_base = dsp->sr;
float f_lp; // dec_lowpass: lowpass_bandwidth/2
float t_bw; // dec_lowpass: transition_bandwidth
int taps; // dec_lowpass: taps
if (dsp->opt_IFmin) IF_sr = IF_SAMPLE_RATE_MIN;
if (IF_sr > sr_base) IF_sr = sr_base;
if (IF_sr < sr_base) {
while (sr_base % IF_sr) IF_sr += 1;
decM = sr_base / IF_sr;
}
f_lp = (IF_sr+20e3)/(4.0*sr_base);
t_bw = (IF_sr-20e3)/*/2.0*/;
if (dsp->opt_IFmin) {
t_bw = (IF_sr-12e3);
}
if (t_bw < 0) t_bw = 10e3;
t_bw /= sr_base;
taps = 4.0/t_bw; if (taps%2==0) taps++;
taps = lowpass_init(f_lp, taps, &ws_dec); // decimate lowpass
if (taps < 0) return -1;
dsp->dectaps = (ui32_t)taps;
dsp->sr_base = sr_base;
dsp->sr = IF_sr; // sr_base/decM
dsp->sps /= (float)decM;
dsp->_spb /= (float)decM;
dsp->decM = decM;
fprintf(stderr, "IF: %d\n", IF_sr);
fprintf(stderr, "dec: %d\n", decM);
}
if (dsp->opt_iq == 5)
{
// look up table, exp-rotation
int W = 2*8; // 16 Hz window
int d = 1; // 1..W , groesster Teiler d <= W von sr_base
int freq = (int)( dsp->xlt_fq * (double)dsp->sr_base + 0.5);
int freq0 = freq; // init
double f0 = freq0 / (double)dsp->sr_base; // init
for (d = W; d > 0; d--) { // groesster Teiler d <= W von sr
if (dsp->sr_base % d == 0) break;
}
if (d == 0) d = 1; // d >= 1 ?
for (k = 0; k < W/2; k++) {
if ((freq+k) % d == 0) {
freq0 = freq + k;
break;
}
if ((freq-k) % d == 0) {
freq0 = freq - k;
break;
}
}
dsp->lut_len = dsp->sr_base / d;
f0 = freq0 / (double)dsp->sr_base;
dsp->ex = calloc(dsp->lut_len+1, sizeof(float complex));
if (dsp->ex == NULL) return -1;
for (n = 0; n < dsp->lut_len; n++) {
t = f0*(double)n;
dsp->ex[n] = cexp(t*2*M_PI*I);
}
dsp->decXbuffer = calloc( dsp->dectaps+1, sizeof(float complex));
if (dsp->decXbuffer == NULL) return -1;
dsp->decMbuf = calloc( dsp->decM+1, sizeof(float complex));
if (dsp->decMbuf == NULL) return -1;
}
if (dsp->opt_iq && dsp->opt_lp)
{
float f_lp; // lowpass_bw
int taps; // lowpass taps: 4*sr/transition_bw
// IF lowpass
f_lp = 24e3; // default
if (dsp->lpIQ_bw) f_lp = dsp->lpIQ_bw/(float)dsp->sr/2.0;
taps = 4*dsp->sr/IF_TRANSITION_BW; if (taps%2==0) taps++;
taps = lowpass_init(1.5*f_lp, taps, &dsp->ws_lpIQ0); if (taps < 0) return -1;
taps = lowpass_init(f_lp, taps, &dsp->ws_lpIQ1); if (taps < 0) return -1;
dsp->lpIQ_fbw = f_lp;
dsp->lpIQtaps = taps;
dsp->lpIQ_buf = calloc( dsp->lpIQtaps+3, sizeof(float complex));
if (dsp->lpIQ_buf == NULL) return -1;
dsp->ws_lpIQ = dsp->ws_lpIQ1;
// dc-offset: if not centered, (acquisition) filter bw = lpIQ_bw + 4kHz
// coarse acquisition:
if (dsp->opt_dc) {
dsp->locked = 0;
dsp->ws_lpIQ = dsp->ws_lpIQ0;
//taps = lowpass_update(1.5*dsp->lpIQ_fbw, dsp->lpIQtaps, dsp->ws_lpIQ); if (taps < 0) return -1;
}
// locked:
//taps = lowpass_update(dsp->lpIQ_fbw, dsp->lpIQtaps, dsp->ws_lpIQ); if (taps < 0) return -1;
// FM lowpass
f_lp = 10e3; // default
if (dsp->lpFM_bw > 0) f_lp = dsp->lpFM_bw/(float)dsp->sr;
taps = 4*dsp->sr/FM_TRANSITION_BW; if (taps%2==0) taps++;
taps = lowpass_init(f_lp, taps, &dsp->ws_lpFM); if (taps < 0) return -1;
dsp->lpFMtaps = taps;
dsp->lpFM_buf = calloc( dsp->lpFMtaps+3, sizeof(float complex));
if (dsp->lpFM_buf == NULL) return -1;
}
memset(&IQdc, 0, sizeof(IQdc));
IQdc.maxlim = dsp->sr;
IQdc.maxcnt = IQdc.maxlim/32; // 32,16,8,4,2,1
if (dsp->decM > 1) {
IQdc.maxlim *= dsp->decM;
IQdc.maxcnt *= dsp->decM;
}
L = dsp->hdrlen * dsp->sps + 0.5;
M = 3*L;
//if (dsp->sps < 6) M = 6*L;
dsp->delay = L/16;
dsp->sample_in = 0;
p2 = 1;
while (p2 < M) p2 <<= 1;
while (p2 < 0x2000) p2 <<= 1; // or 0x4000, if sample not too short
M = p2;
dsp->DFT.N = p2;
dsp->DFT.LOG2N = log(dsp->DFT.N)/log(2)+0.1; // 32bit cpu ... intermediate floating-point precision
//while ((1 << dsp->DFT.LOG2N) < dsp->DFT.N) dsp->DFT.LOG2N++; // better N = (1 << LOG2N) ...
K = M-L - dsp->delay; // L+K < M
dsp->DFT.sr = dsp->sr;
dsp->K = K;
dsp->L = L;
dsp->M = M;
dsp->Nvar = L; // wenn Nvar fuer xnorm, dann Nvar=rshd.L
dsp->bufs = (float *)calloc( M+1, sizeof(float)); if (dsp->bufs == NULL) return -100;
dsp->match = (float *)calloc( L+1, sizeof(float)); if (dsp->match == NULL) return -100;
dsp->xs = (float *)calloc( M+1, sizeof(float)); if (dsp->xs == NULL) return -100;
dsp->qs = (float *)calloc( M+1, sizeof(float)); if (dsp->qs == NULL) return -100;
dsp->rawbits = (char *)calloc( 2*dsp->hdrlen+1, sizeof(char)); if (dsp->rawbits == NULL) return -100;
for (i = 0; i < M; i++) dsp->bufs[i] = 0.0;
for (i = 0; i < L; i++) {
pos = i/dsp->sps;
t = (i - pos*dsp->sps)/dsp->sps - 0.5;
b1 = ((dsp->hdr[pos] & 0x1) - 0.5)*2.0;
b = b1*pulse(t, sigma);
if (pos > 0) {
b0 = ((dsp->hdr[pos-1] & 0x1) - 0.5)*2.0;
b += b0*pulse(t+1, sigma);
}
if (pos < dsp->hdrlen-1) {
b2 = ((dsp->hdr[pos+1] & 0x1) - 0.5)*2.0;
b += b2*pulse(t-1, sigma);
}
dsp->match[i] = b;
}
normMatch = sqrt( norm2_vect(dsp->match, L) );
for (i = 0; i < L; i++) {
dsp->match[i] /= normMatch;
}
dsp->DFT.xn = calloc(dsp->DFT.N+1, sizeof(float)); if (dsp->DFT.xn == NULL) return -1;
dsp->DFT.Fm = calloc(dsp->DFT.N+1, sizeof(float complex)); if (dsp->DFT.Fm == NULL) return -1;
dsp->DFT.X = calloc(dsp->DFT.N+1, sizeof(float complex)); if (dsp->DFT.X == NULL) return -1;
dsp->DFT.Z = calloc(dsp->DFT.N+1, sizeof(float complex)); if (dsp->DFT.Z == NULL) return -1;
dsp->DFT.cx = calloc(dsp->DFT.N+1, sizeof(float complex)); if (dsp->DFT.cx == NULL) return -1;
dsp->DFT.ew = calloc(dsp->DFT.LOG2N+1, sizeof(float complex)); if (dsp->DFT.ew == NULL) return -1;
// FFT window
// a) N2 = N
// b) N2 < N (interpolation)
dsp->DFT.win = calloc(dsp->DFT.N+1, sizeof(float complex)); if (dsp->DFT.win == NULL) return -1; // float real
dsp->DFT.N2 = dsp->DFT.N;
//dsp->DFT.N2 = dsp->DFT.N/2 - 1; // N=2^log2N
dft_window(&dsp->DFT, 1);
for (n = 0; n < dsp->DFT.LOG2N; n++) {
k = 1 << n;
dsp->DFT.ew[n] = cexp(-I*M_PI/(float)k);
}
m = calloc(dsp->DFT.N+1, sizeof(float)); if (m == NULL) return -1;
for (i = 0; i < L; i++) m[L-1 - i] = dsp->match[i]; // t = L-1
while (i < dsp->DFT.N) m[i++] = 0.0;
rdft(&dsp->DFT, m, dsp->DFT.Fm);
free(m); m = NULL;
if (dsp->opt_iq)
{
if (dsp->nch < 2) return -1;
dsp->N_IQBUF = dsp->DFT.N;
dsp->rot_iqbuf = calloc(dsp->N_IQBUF+1, sizeof(float complex)); if (dsp->rot_iqbuf == NULL) return -1;
}
dsp->fm_buffer = (float *)calloc( M+1, sizeof(float)); if (dsp->fm_buffer == NULL) return -1; // dsp->bufs[]
return K;
}
int free_buffers(dsp_t *dsp) {
if (dsp->match) { free(dsp->match); dsp->match = NULL; }
if (dsp->bufs) { free(dsp->bufs); dsp->bufs = NULL; }
if (dsp->xs) { free(dsp->xs); dsp->xs = NULL; }
if (dsp->qs) { free(dsp->qs); dsp->qs = NULL; }
if (dsp->rawbits) { free(dsp->rawbits); dsp->rawbits = NULL; }
if (dsp->DFT.xn) { free(dsp->DFT.xn); dsp->DFT.xn = NULL; }
if (dsp->DFT.ew) { free(dsp->DFT.ew); dsp->DFT.ew = NULL; }
if (dsp->DFT.Fm) { free(dsp->DFT.Fm); dsp->DFT.Fm = NULL; }
if (dsp->DFT.X) { free(dsp->DFT.X); dsp->DFT.X = NULL; }
if (dsp->DFT.Z) { free(dsp->DFT.Z); dsp->DFT.Z = NULL; }
if (dsp->DFT.cx) { free(dsp->DFT.cx); dsp->DFT.cx = NULL; }
if (dsp->DFT.win) { free(dsp->DFT.win); dsp->DFT.win = NULL; }
if (dsp->opt_iq)
{
if (dsp->rot_iqbuf) { free(dsp->rot_iqbuf); dsp->rot_iqbuf = NULL; }
}
// decimate
if (dsp->opt_iq == 5)
{
if (dsp->decXbuffer) { free(dsp->decXbuffer); dsp->decXbuffer = NULL; }
if (dsp->decMbuf) { free(dsp->decMbuf); dsp->decMbuf = NULL; }
if (dsp->ex) { free(dsp->ex); dsp->ex = NULL; }
if (ws_dec) { free(ws_dec); ws_dec = NULL; }
}
// IF lowpass
if (dsp->opt_iq && dsp->opt_lp)
{
if (dsp->ws_lpIQ0) { free(dsp->ws_lpIQ0); dsp->ws_lpIQ0 = NULL; }
if (dsp->ws_lpIQ1) { free(dsp->ws_lpIQ1); dsp->ws_lpIQ1 = NULL; }
if (dsp->lpIQ_buf) { free(dsp->lpIQ_buf); dsp->lpIQ_buf = NULL; }
if (dsp->ws_lpFM) { free(dsp->ws_lpFM); dsp->ws_lpFM = NULL; }
if (dsp->lpFM_buf) { free(dsp->lpFM_buf); dsp->lpFM_buf = NULL; }
}
if (dsp->fm_buffer) { free(dsp->fm_buffer); dsp->fm_buffer = NULL; }
return 0;
}
/* ------------------------------------------------------------------------------------ */
int find_header(dsp_t *dsp, float thres, int hdmax, int bitofs, int opt_dc) {
ui32_t k = 0;
ui32_t mvpos0 = 0;
int mp;
int header_found = 0;
int herrs;
while ( f32buf_sample(dsp, 0) != EOF ) {
k += 1;
if (k >= dsp->K-4) {
mvpos0 = dsp->mv_pos;
mp = getCorrDFT(dsp); // correlation score -> dsp->mv
//if (option_auto == 0 && dsp->mv < 0) mv = 0;
k = 0;
}
else {
dsp->mv = 0.0;
continue;
}
if (dsp->mv > thres || dsp->mv < -thres) {
if (dsp->opt_dc) { // Problem: FM-gain
if (dsp->opt_iq < 2) dsp->Df += dsp->dDf*0.4;
else {
double ofs = fabs(dsp->dDf); // (iq-decode controls FM-gain)
if (ofs > 200.0)
{
dsp->Df += dsp->dDf * 2/3.0;
}
if (ofs > 1000.0) { //dsp->opt_lp
if (dsp->locked) {
dsp->locked = 0;
dsp->ws_lpIQ = dsp->ws_lpIQ0;
// alt: lowpass_update(1.5*dsp->lpIQ_fbw, dsp->lpIQtaps, dsp->ws_lpIQ);
}
}
else {
if (dsp->locked == 0) {
dsp->locked = 1;
dsp->ws_lpIQ = dsp->ws_lpIQ1;
// alt: lowpass_update(dsp->lpIQ_fbw, dsp->lpIQtaps, dsp->ws_lpIQ);
}
}
}
}
if (dsp->mv_pos > mvpos0) {
header_found = 0;
herrs = headcmp(dsp, opt_dc);
if (herrs <= hdmax) header_found = 1; // max bitfehler in header
if (header_found) return 1;
}
}
}
return EOF;
}
/* ------------------------------------------------------------------------------------ */
#else
// external FSK demod: read float32 soft symbols
float read_wav_header(pcm_t *pcm, FILE *fp) {}
int f32buf_sample(dsp_t *dsp, int inv) {}
int read_slbit(dsp_t *dsp, int *bit, int inv, int ofs, int pos, float l, int spike) {}
int read_softbit(dsp_t *dsp, hsbit_t *shb, int inv, int ofs, int pos, float l, int spike) {}
int read_softbit2p(dsp_t *dsp, hsbit_t *shb, int inv, int ofs, int pos, float l, int spike, hsbit_t *shb1) {}
int init_buffers(dsp_t *dsp) {}
int free_buffers(dsp_t *dsp) {}
int find_header(dsp_t *dsp, float thres, int hdmax, int bitofs, int opt_dc) {}
#endif
static float cmp_hdb(hdb_t *hdb) { // bit-errors?
int i, j;
int headlen = hdb->len;
int berrs1 = 0, berrs2 = 0;
i = 0;
j = hdb->bufpos;
while (i < headlen) {
if (j < 0) j = headlen-1;
if (hdb->buf[j] != hdb->hdr[headlen-1-i]) berrs1 += 1;
j--;
i++;
}
i = 0;
j = hdb->bufpos;
while (i < headlen) {
if (j < 0) j = headlen-1;
if ((hdb->buf[j]^0x01) != hdb->hdr[headlen-1-i]) berrs2 += 1;
j--;
i++;
}
if (berrs2 < berrs1) return (-headlen+berrs2)/(float)headlen;
else return ( headlen-berrs1)/(float)headlen;
return 0;
}
int find_binhead(FILE *fp, hdb_t *hdb, float *score) {
int bit;
int headlen = hdb->len;
float mv;
//*score = 0.0;
while ( (bit = fgetc(fp)) != EOF )
{
bit &= 1;
hdb->bufpos = (hdb->bufpos+1) % headlen;
hdb->buf[hdb->bufpos] = 0x30 | bit; // Ascii
mv = cmp_hdb(hdb);
if ( fabs(mv) > hdb->thb ) {
*score = mv;
return 1;
}
}
return EOF;
}
static float corr_softhdb(hdb_t *hdb) { // max score in window probably not needed
int i, j;
int headlen = hdb->len;
double sum = 0.0;
double normx = 0.0,
normy = 0.0;
float x, y;
i = 0;
j = hdb->bufpos + 1;
while (i < headlen) {
if (j >= headlen) j = 0;
x = hdb->sbuf[j];
y = 2.0*(hdb->hdr[i]&0x1) - 1.0;
sum += y * hdb->sbuf[j];
normx += x*x;
normy += y*y;
j++;
i++;
}
sum /= sqrt(normx*normy);
return sum;
}
int f32soft_read(FILE *fp, float *s) {
unsigned int word = 0;
short *b = (short*)&word;
float *f = (float*)&word;
int bps = 32;
if (fread( &word, bps/8, 1, fp) != 1) return EOF;
if (bps == 32) {
*s = *f;
}
else {
if (bps == 8) { *b -= 128; }
*s = *b/128.0;
if (bps == 16) { *s /= 256.0; }
}
return 0;
}
int find_softbinhead(FILE *fp, hdb_t *hdb, float *score) {
int headlen = hdb->len;
float sbit;
float mv;
//*score = 0.0;
while ( f32soft_read(fp, &sbit) != EOF )
{
hdb->bufpos = (hdb->bufpos+1) % headlen;
hdb->sbuf[hdb->bufpos] = sbit;
mv = corr_softhdb(hdb);
if ( fabs(mv) > hdb->ths ) {
*score = mv;
return 1;
}
}
return EOF;
}
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