巴特沃斯滤波器

来源：互联网发布：tensorflow教程视频编辑：程序博客网时间：2024/05/30 05:30
#include "math.h"#include<stdio.h>#include<string.h>#include<stdlib.h>#define MAX 2500#define PI 3.1415926/***************************************************************************************** biliner(int fc,int N,int fs,float* x)*  参数说明  fc 截止频率*            fs 采样率*            N  (1=<N<=3)  阶数*            *x 传入的待滤波数组*双线性法基于巴特沃斯的数字滤波器    ****************************************************************************************/using namespace std;void biliner(int fc,int N,int fs,float *x){ //定义变量 long i=0;    float W,Wc,t,y[MAX];//MAX是3000个点 //转化为数字角频率 W=2*PI*fc/fs; //预畸变 Wc=2*fs*tan(w/2); //去归一化影响 t=2*fs/wc;     switch(N)     {  /*一阶情况*/  case 1:    //Hs=1/(p+1);    y[0]=x[0]/(1+t);    for(i=1;i<MAX;i++)     y[i]=(x[i]+x[i-1]-(1-t)*y[i-1])/(1+t);    break;    /*二阶情况*/   case 2:     //Hs=1/(p*p+1.414*p+1);    y[0]=x[0]/(t*t+1.414*t+1);    y[1]=(x[1]+2*x[0]-(2-2*t*t)*y[0])/(t*t+1.414*t+1);    for(i=2;i<MAX;i++)     y[i]=(x[i]+2*x[i-1]+x[i-2]-(2-2*t*t)*y[i-1]-(1-1.414*t+t*t)*y[i-2])/(t*t+1.414*t+1);    break;    /*三阶*/   case 3:    y[0]=x[0]/(t*t*t+2*t*t+2*t+1);    y[1]=(x[1]+3*x[0]-(3-3*t*t*t-2*t*t+2*t)*y[0])/(t*t*t+2*t*t+2*t+1);    y[2]=(x[2]+3*x[1]+3*x[0]-(3-3*t*t*t-2*t*t+2*t)*y[1]-(3*t*t*t-2*t*t-2*t+3)*y[0])/(t*t*t+2*t*t+2*t+1);    for(i=3; i < MAX ;i++)     y[i]=(x[i]+3*x[i-1]+3*x[i-2]+x[i-3]-(3-3*t*t*t-2*t*t+2*t)*y[i-1]-(3*t*t*t-2*t*t-2*t+3)*y[i-2]-(1-t*t*t+2*t*t-2*t)*y[i-3])/(t*t*t+2*t*t+2*t+1);       break;    default:    return ;break;  }    for(i=0;i<MAX;i++)    x[i]=y[i];  //输出x[]      return;}int main(int argc, char *argv[]){ float x[MAX]; int i,lenth,m; FILE *fpx=fopen("newdata.txt","w"); FILE *fp=fopen("ChannelData.txt","r"); if(fp==NULL||fpx==NULL) { printf("失败!!!\n"); return 0; } for(i=0;i<MAX;i++) fscanf(fp,"%f ",&x[i]);//输入x[]  biliner(2,200,2,x);  for(i=0;i<MAX;i++)  fprintf(fpx,"%f\n",x[i]);//输出x[]   fclose(fpx);  fclose(fp);}
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