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-rw-r--r--FIR/firmath.c247
1 files changed, 247 insertions, 0 deletions
diff --git a/FIR/firmath.c b/FIR/firmath.c
new file mode 100644
index 0000000..3fdf20b
--- /dev/null
+++ b/FIR/firmath.c
@@ -0,0 +1,247 @@
+//
+// 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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