adaptive.c

来自「adaptive filtering IIR and FIR」· C语言 代码 · 共 132 行

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

/*		Decimal to Hex function		*/
void DecToHex(double *inPtr, int cnt){

	double temp = 0;
	double modd = 0;
	short int hexval = 0;
	short int jcnt;	

	FILE *hexoutput;
	hexoutput= fopen("hexoutput.dat","w");

	for(jcnt=0;jcnt<=cnt-1;jcnt++){
		temp = *(inPtr + jcnt) * 32768;
		modd = temp - floor(temp);
		if(modd >= 0.5)
			temp = ceil(temp);
		else
			temp = floor(temp);
		hexval = (short int)temp;

		fprintf(hexoutput,"%s","	.word 0x");
		fprintf(hexoutput,"%X",hexval);
		fprintf(hexoutput,"\n");
	}

	fcloseall();
	return;
}

/* --------		MAIN	-------- */
void main()
{


  #define NL	32		     /* length of FIR filter            */
  #define LEN	500
  //long yn = 0;               /* y(n), output from filter        */
  short int yn = 0;
  short int outyn[LEN];
  double xn[LEN];
  short int xnbuf[NL];
  short int w[NL];
  int i,j,k,n;
  //int mu = 338;		    /* 33(0.001); 338(0.01); 655(0.02)  */
  short int t = 0x028F;
  short int mu_err;
  short int dn = 0;
  short int err;
  short int err1[LEN];
  double temp;
  double modd;
  int a;					// A reg


  FILE *yn_out;             /* file pointer of y(n)             */
  FILE *w_out;              /* file pointer of w(0)             */
  FILE *err_out;            /* file pointer of e(n)             */
  yn_out = fopen("out_int.dat","w");/* open file for output y(n)*/
  w_out = fopen("w_int.dat","w");   /* coefficient file         */
  err_out = fopen("err_int.dat","w");/* error signal file       */


  for(i=0;i<LEN+1;i++){
	  xn[i] = 0.25 * sin(2*i*3.141516/16);
  }

  for(k=0;k<NL;k++)
  {                     /* clear signal and coefficient buffers */
    xnbuf[k]=0;
    w[k] = 0;
  }

  for(n=0;n<LEN;n++)
  {          
// Clear sample buffer
    for (i=NL-1;i>0;i--)
    {
      xnbuf[i]=xnbuf[i-1];   
    }

// Delay the sample buffer
    xnbuf[0]=dn;		
	temp = (double)(xn[n] * 32768);
	modd = temp - floor(temp);
	if(modd >= 0.5)
		temp = ceil(temp);
	else
		temp = floor(temp);
	dn = (short int)temp;			// dn = latest input

// FIR filtering
    yn = 0; 
    for (j=0; j< NL; j++)    
    {
		a = xnbuf[j] * w[j];	
		a <<= 1;	
		yn = yn + (short int)(a >> 16);
    } 
	outyn[n] = yn;
 
    err = dn-yn;					//e(n) = d(n) - y(n)
	err1[n] = err;
	a = t * err;
	a <<= 1;
	mu_err = (short int)(a >> 16);
    
//update filter coeffificient                         

    for (k=0; k< NL; k++)
    {
		a = mu_err * xnbuf[k];
		a <<= 1;
		w[k] = w[k] + (short int)(a >> 16);
    }
			
    fprintf(yn_out,"%f\n", (float)yn/32768 );
//    fprintf(w_out,"%f\n", (float)w[n]/32768 );
    fprintf(err_out,"%f\n",(float)err1[n]/32768 );
	
  }
  printf("Finish");					//complete filtering 
  fcloseall();						//close all opened files


//	DecToHex(w,32);
}