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IQ baseband decode: samplecount overflow

pull/18/head
Zilog80 2019-08-24 07:42:03 +02:00
rodzic 8f869a1efa
commit 729c90ce46
2 zmienionych plików z 14 dodań i 10 usunięć
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18
demod/mod/demod_mod.c
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@ -381,7 +381,7 @@ static int get_SNR(dsp_t *dsp) {
} }
static int res = 1; // 1..10 Hz, exp_lut resolution static ui32_t res = 1; // 1..10 Hz, exp_lut resolution
static float *ws_dec; static float *ws_dec;
static double sinc(double x) { static double sinc(double x) {
@ -400,9 +400,9 @@ static int decimate_init(int taps, float f) {
if ( taps < 1 ) taps = 1; if ( taps < 1 ) taps = 1;
h = (double*)calloc( taps+1, sizeof(double)); h = (double*)calloc( taps+1, sizeof(double)); if (h == NULL) return -1;
w = (double*)calloc( taps+1, sizeof(double)); w = (double*)calloc( taps+1, sizeof(double)); if (w == NULL) return -1;
ws_dec = (float*)calloc( taps+1, sizeof(float)); ws_dec = (float*)calloc( taps+1, sizeof(float)); if (ws_dec == NULL) return -1;
for (n = 0; n < taps; n++) { 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 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
@ -420,8 +420,8 @@ static int decimate_init(int taps, float f) {
return taps; return taps;
} }
static float complex lowpass(float complex buffer[], int sample, int M) { static float complex lowpass(float complex buffer[], ui32_t sample, ui32_t M) {
int n; ui32_t n;
double complex w = 0; double complex w = 0;
for (n = 0; n < M; n++) { for (n = 0; n < M; n++) {
w += buffer[(sample+n+1)%M]*ws_dec[M-1-n]; w += buffer[(sample+n+1)%M]*ws_dec[M-1-n];
@ -441,11 +441,13 @@ int f32buf_sample(dsp_t *dsp, int inv) {
if (dsp->opt_iq) { if (dsp->opt_iq) {
if (dsp->opt_iq == 5) { if (dsp->opt_iq == 5) {
ui32_t s_reset = dsp->dectaps*dsp->sr_base; // dsp->sr_base % res == 0
int j; int j;
if ( f32read_cblock(dsp) < dsp->decM ) return EOF; if ( f32read_cblock(dsp) < dsp->decM ) return EOF;
for (j = 0; j < dsp->decM; j++) { for (j = 0; j < dsp->decM; j++) {
dsp->decXbuffer[dsp->sample_dec % dsp->dectaps] = dsp->decMbuf[j] * dsp->ex[dsp->sample_dec % (dsp->sr_base/res)]; dsp->decXbuffer[dsp->sample_dec % dsp->dectaps] = dsp->decMbuf[j] * dsp->ex[dsp->sample_dec % (dsp->sr_base/res)];
dsp->sample_dec += 1; dsp->sample_dec += 1;
if (dsp->sample_dec == s_reset) dsp->sample_dec = 0;
} }
z = lowpass(dsp->decXbuffer, dsp->sample_dec, dsp->dectaps); z = lowpass(dsp->decXbuffer, dsp->sample_dec, dsp->dectaps);
} }
@ -774,7 +776,9 @@ int init_buffers(dsp_t *dsp) {
t_bw /= sr_base; t_bw /= sr_base;
taps = 4.0/t_bw; if (taps%2==0) taps++; taps = 4.0/t_bw; if (taps%2==0) taps++;
dsp->dectaps = decimate_init(taps, f_lp); taps = decimate_init(taps, f_lp);
if (taps < 0) return -1;
dsp->dectaps = (ui32_t)taps;
dsp->sr_base = sr_base; dsp->sr_base = sr_base;
dsp->sr = IF_sr; // sr_base/decM dsp->sr = IF_sr; // sr_base/decM

6
demod/mod/demod_mod.h
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@ -92,13 +92,13 @@ typedef struct {
double V_signal; double V_signal;
double SNRdB; double SNRdB;
int sr_base;
int decM; int decM;
int dectaps; ui32_t sr_base;
ui32_t dectaps;
ui32_t sample_dec;
float complex *decXbuffer; float complex *decXbuffer;
float complex *decMbuf; float complex *decMbuf;
float complex *ex; // exp_lut float complex *ex; // exp_lut
ui32_t sample_dec;
double xlt_fq; double xlt_fq;
} dsp_t; } dsp_t;