MC100/Applications/math/Fir.c

/*
 * Filter Coefficients (C Source) generated by the Filter Design and Analysis Tool
 * Generated by MATLAB(R) 9.9 and Signal Processing Toolbox 8.5.
 * Generated on: 06-Oct-2022 12:50:19
 */

/*
 * 离散时间 FIR 滤波器(实数)
 * ----------------
 * 滤波器结构  : 直接型 FIR
 * 滤波器长度  : 16
 * 稳定     : 是
 * 线性相位   : 是 (Type 2)
 */

/* General type conversion for MATLAB generated C-code  */
//#include "tmwtypes.h"
/* 
 * Expected path to tmwtypes.h 
 * D:\Program Files\R2020b\extern\include\tmwtypes.h 
 */
/*
 * Warning - Filter coefficients were truncated to fit specified data type.  
 *   The resulting response may not match generated theoretical response.
 *   Use the Filter Design & Analysis Tool to design accurate
 *   single-precision filter coefficients.
 */

#include "math/fir.h"

static const float Fir_Ceofs[16] = {
	0.007895005867,  0.01734124683,  0.03257999197,  0.05209516734,  0.07380001992,
	 0.09460353851,   0.1110314056,   0.1201113388,   0.1201113388,   0.1110314056,
	 0.09460353851,  0.07380001992,  0.05209516734,  0.03257999197,  0.01734124683,
	0.007895005867

};

void Fir_init(Fir_t *fir) {
	for (int i = 0; i < FIR_Ceof_Len; i++) {
		fir->X[0] = 0.0f;
	}
	fir->k = 0;
}


float Fir_Filter(Fir_t *fir, float in) {
	float out = 0;
	fir->X[fir->k] = in;
	for (int i = 1; i <= FIR_Ceof_Len; i++) {
		out += Fir_Ceofs[i-1] * fir->X[(i+fir->k) % FIR_Ceof_Len];
	}
	fir->k = (fir->k + 1) % FIR_Ceof_Len;
	return out;
}