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//
// firmath.c
// FIR_rect_win
//
// Created by Jacky Jack on 04/07/2021.
//
#include "firmath.h"
/*
void window_func_rect(double *w, int N1) {
int j;
for (j=0;j<N1;j++) {
w[j] = 1.0;
}
}
*/
void fir_init(fir_t *fir, uint32_t taps) {
int i;
for (i=0;i<taps;i++) {
fir->fir_coef[i] = (double)0.0;
}
fir->num_taps = taps;
}
void firw_init(firw_t *fir_win, uint32_t taps) {
int i;
for (i=0;i<taps;i++) {
fir_win->win_coef[i] = (double)0.0;
}
fir_win->num_taps = taps;
}
double math_sinx(double x) {
if (x>-1.0E-5 && x < 1.0E-5) return (1.0);
return sin(x)/x;
}
void fir_sinc_lp(fir_t *fir, double omega_c) {
int i;
double arg=0.0;
//should set 2fc?!
printf("omega_c=%f\n",omega_c);
for (i=0;i<fir->num_taps;i++) {
arg = (double)i-(double)(fir->num_taps-1)/2.0;
fir->fir_coef[i] = omega_c * math_sinx(omega_c*arg*M_PI);
}
}
void fir_sinc_hp(fir_t *fir, double omega_c) {
int i;
double arg=0.0;
int even = fir->num_taps%2 ? 0: 1;
//should set 2fc?!
printf("omega_c=%f\n",omega_c);
if (even) {
for (i=0;i<fir->num_taps;i++) {
arg = (double)i-(double)(fir->num_taps-1)/2.0;
if (arg == 0.0) {
fir->fir_coef[i] = 0.0;
} else {
//from IOWA
fir->fir_coef[i] = cos(omega_c*arg*M_PI)/M_PI/arg + cos(arg*M_PI);
}
}
} else {
for (i=0;i<fir->num_taps;i++) {
arg = (double)i-(double)(fir->num_taps-1)/2.0;
fir->fir_coef[i] = math_sinx(arg*M_PI)-omega_c * math_sinx(omega_c*arg*M_PI);
}
}
}
void fir_sinc_bp(fir_t *fir, double omega_c1, double omega_c2) {
int i;
double arg=0.0;
//should set 2fc?!
printf("omega_c1=%f\n",omega_c1);
printf("omega_c2=%f\n",omega_c2);
for (i=0;i<fir->num_taps;i++) {
arg = (double)i-(double)(fir->num_taps-1)/2.0;
if (arg==0.0) {
fir->fir_coef[i] = 0.0;
} else {
//fir->fir_coef[i] = math_sinx(arg*M_PI) - omega_c2 * math_sinx(omega_c2*arg*M_PI) - omega_c1 * math_sinx(omega_c1*arg*M_PI);
fir->fir_coef[i] = (cos(omega_c1*arg*M_PI) - cos(omega_c2*arg*M_PI))/M_PI/arg;
}
}
}
void fir_sinc_bs(fir_t *fir, double omega_c1, double omega_c2) {
int i;
double arg=0.0;
//should set 2fc?!
printf("omega_c1=%f\n",omega_c1);
printf("omega_c2=%f\n",omega_c2);
for (i=0;i<fir->num_taps;i++) {
arg = (double)i-(double)(fir->num_taps-1)/2.0;
if (arg==0.0) {
fir->fir_coef[i] = 0.0;
} else {
//fir->fir_coef[i] = math_sinx(arg*M_PI) - omega_c2 * math_sinx(omega_c2*arg*M_PI) - omega_c1 * math_sinx(omega_c1*arg*M_PI);
fir->fir_coef[i] = math_sinx(arg*M_PI) - omega_c2*math_sinx(omega_c2*arg*M_PI) - omega_c1*math_sinx(omega_c1*arg*M_PI);
}
}
}
void fir_convolute(fir_t *fir,firw_t *firw) {
int i=0;
for (i=0;i<fir->num_taps;i++) {
fir->fir_coef[i] = fir->fir_coef[i]*firw->win_coef[i];
}
}
void firw_rect(firw_t *fir_win) {
int i;
int n1 = fir_win->num_taps/2;
int even = fir_win->num_taps%2 ? 0: 1;
if (even) n1+=1;
for (i=0;i<n1;i++) {
fir_win->win_coef[i] = 1.0;
}
for (i=0;i<n1;i++) {
fir_win->win_coef[fir_win->num_taps-1-i] = fir_win->win_coef[i];
}
}
void firw_hamming(firw_t *fir_win) {
int i;
double dN=0;
double arg=0;
//double p=0;
//double arg=0;
int n1 = fir_win->num_taps/2;
int even = fir_win->num_taps%2 ? 0: 1;
if (!even) n1+=1;
dN = fir_win->num_taps +1;
for (i=0;i<n1;i++) {
//arg = (double)i-(double)(fir_win->num_taps-1)/2.0;
//fir_win->win_coef[i] = 0.54+(1-0.54)*cos(2*M_PI*arg/n1);
//fir_win->win_coef[i] = 0.54+(1-0.54)*cos(2*M_PI*i/n1);
arg = (double)i-(double)(fir_win->num_taps-1)/2.0;
fir_win->win_coef[i] = 0.54+0.46*cos(2*M_PI*arg/fir_win->num_taps);
}
//fold
for (i=0;i<n1;i++) {
//arg = (double)i-(double)(fir_win->num_taps-1)/2.0;
//fir_win->win_coef[i] = 0.54+(1-0.54)*cos(2*M_PI*arg/n1);
fir_win->win_coef[fir_win->num_taps-1-i] = fir_win->win_coef[i];
}
}
void firw_hanning(firw_t *fir_win) {
int i;
double dN=0;
double arg=0;
int n1 = fir_win->num_taps/2;
int even = fir_win->num_taps%2 ? 0: 1;
if (!even) n1+=1;
dN = fir_win->num_taps +1;
for (i=0;i<n1;i++) {
arg = (double)i-(double)(fir_win->num_taps-1)/2.0;
fir_win->win_coef[i] = 0.5+(1-0.5)*cos(2*M_PI*arg/fir_win->num_taps);
}
//fold
for (i=0;i<n1;i++) {
fir_win->win_coef[fir_win->num_taps-1-i] = fir_win->win_coef[i];
}
}
void firw_blackman(firw_t *firw) {
int i;
double dN=0;
double arg=0;
int n1 = firw->num_taps/2;
int even = firw->num_taps%2 ? 0: 1;
if (!even) n1+=1;
dN = firw->num_taps +1;
for (i=0;i<n1;i++) {
arg = (double)i-(double)(firw->num_taps-1)/2.0;
/*
firw->win_coef[i] = 0.42
+0.50*cos(2*M_PI*arg/(firw->num_taps))
+0.08*cos(4*M_PI*arg/(firw->num_taps));
*/
firw->win_coef[i] = 0.42
+0.50*cos(2*M_PI*arg/(firw->num_taps-1))
+0.08*cos(4*M_PI*arg/(firw->num_taps-1));
}
//fold
for (i=0;i<n1;i++) {
firw->win_coef[firw->num_taps-1-i] = firw->win_coef[i];
}
}
void fir_print_matlab(fir_t *fir) {
int i;
printf("f=[\n");
for (i=0;i<fir->num_taps;i++) {
printf("%f\n",fir->fir_coef[i]);
}
printf("];\n");
}
void firw_print_matlab(firw_t *firw) {
int i;
printf("w=[\n");
for (i=0;i<firw->num_taps;i++) {
printf("%f\n",firw->win_coef[i]);
}
printf("];\n");
}
void fir_print_c(fir_t *fir) {
int i;
printf("double f=[\n");
for (i=0;i<fir->num_taps;i++) {
printf("%f,\n",fir->fir_coef[i]);
}
printf("];\n");
}
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