#include <stdio.h> const  int length = 180 /*语音帧长为180点＝22.5ms@8kHz采样*/ void  filter(int xin[ ],int xout[ ],int n,float h[ ]); /*滤波子程序说明*/ /*19点滤波器系数*/ static  float h[19]=     {0.01218354,-0.009012882,-0.02881839,-0.04743239,-0.04584568, -0.008692503,0.06446265,0.1544655,0.2289794,0.257883, 0.2289794,0.1544655,0.06446265,-0.008692503,-0.04584568, -0.04743239,-0.02881839,-0.009012882,0.01218354}; static  int x1[length+20]; /*低通滤波浮点子程序*/ void  filter(int xin[ ],int xout[ ],int n,float h[ ]) {     int i,j;     float sum;     for(i=0;i<length;i++) x1[n+i-1]=xin[i];     for (i=0;i<length;i++)     {         sum=0.0;         for(j=0;j<n;j++) sum+=h[j]*x1[i-j+n-1];         xout[i]=(int)sum;     }     for(i=0;i<(n-1);i++) x1[n-i-2]=xin[length-1-i]; }   /*主程序*/ void  main( ) {     FILE    *fp1,*fp2;     int     frame,indata[length],outdata[length];     fp1=fopen(insp.dat,"rb");              /*输入语音文件*/     fp2=fopen(outsp.dat,"wb");           /*滤波后语音文件*/       frame=0;     while(feof(fp1)==0)     {         frame++;         printf("frame=%d/n",frame);         for(i=0;i<length;i++)  indata[i]=getw(fp1);        /*取一帧语音数据*/         filter(indata,outdata,19,h);            /*调用低通滤波子程序*/         for(i=0;i<length;i++)  putw(outdata[i],fp2);     /*将滤波后的样值写入文件*/     }     fcloseall( );                   /*关闭文件*/     return(0); }

#include <stdio.h> const int length=180; void  filter(int xin[ ],int xout[ ],int n,int h[ ]); static int  h[19]={399,-296,-945,-1555,-1503,-285,2112,5061,7503,8450,     7503,5061,2112,-285,-1503,-1555,-945,-296,399};           /*Q15*/ static int  x1[length+20]; /*低通滤波定点子程序*/ void  filter(int xin[ ],int xout[ ],int n,int h[ ]) {     int i,j;     long sum;     for(i=0;i<length;i++) x1[n+i-1]=xin[i];     for (i=0;i<length;i++)     {         sum=0;         for(j=0;j<n;j++)  sum+=(long)h[j]*x1[i-j+n-1];         xout[i]=sum>>15;     }     for(i=0;i<(n-1);i++) x1[n-i-2]=xin[length-i-1]; }