www.pudn.com > DSP6711filter.rar > main.c

//IIR 19阶butterworth低通滤波器 
//采样频率fs=40k,截止频率fc=10k 
//吴臻志作于2006/12/8 
 
#include  
#include "math.h" 
#define N 20 
#define Length 128 
float input[Length],output[Length]; 
 
const float b[N] = { 
1.532234455e-005,0.0002911245683, 0.002620120998,  0.01484735217,  0.05938940868, 
     0.1781682223,    0.415725857,   0.7720623016,    1.158093452,    1.415447593, 
      1.415447593,    1.158093452,   0.7720623016,    0.415725857,   0.1781682223, 
    0.05938940868,  0.01484735217, 0.002620120998,0.0002911245683, 1.532234455e-005 
  }; 
const float a[N] = { 
   1,-1.341377151e-015,    2.582051277,-3.020413399e-015,    2.629014969, 
  -2.643519736e-015,    1.364365935,-1.157850946e-015,   0.3901539147,-2.727497971e-016, 
    0.06217307225,-3.461429587e-017, 0.005333174486,-2.247626948e-018,0.0002255303698, 
  -6.607450878e-020,3.915039997e-006,-6.698137419e-022,1.784284365e-008,-9.904767921e-025 
	}; 
 
void filter(){ 
 
		int n,j; 
		float temp; 
		float x[N],y[N]; 
		//采样频率fs=40k,截止频率fc=10k 
		for (j=0;j0;j--){ 
						x[j]=x[j-1]; 
						y[j]=y[j-1]; 
			} 
				 
		} 
while(1); 
} 
void test1(){ 
		int n; 
		for (n=0;n