fixpoint_cascadeiirtest.c

CHP 5 - Real-Time Digital Signal Processing: Implementations and Applications, Second Edition by Sen

// 
//  Project: Exercise 5.24 implementation of fixed-point IIR filter in direct form-II - Chapter 5
//  File name: fixPoint_cascadeIIRTest.c   
//
//  Description: This is the test program for a fixed-point IIR filter in direct form I
//
//  For the book "Real Time Digital Signal Processing: 
//                Implementation and Application, 2nd Ed"
//                By Sen M. Kuo, Bob H. Lee, and Wenshun Tian
//                Publisher: John Wiley and Sons, Ltd
//
//  Tools used: CCS v.2.12.07
//              TMS320VC5510 DSK Rev-C
//

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

#include "cascadeIIR.h"
#include "fdacoefsMATLAB.h"

#define SECTIONS   ((MWSPT_NSEC-1)/2)

 
// Filter coefficients obtained from example 5.14 MATLAB FDATool
short b[SECTIONS][3];
short a[SECTIONS][3];

// Filter delay line
short w[SECTIONS][3];

void main()
{
  short  in,gain;
  short  i,j,k,y;
  FILE   *fpIn,*fpOut;
  char   temp[2];
  long   t32;

  // Open file for read input data
  if ((fpIn = fopen(".\\data\\in.pcm", "rb"))== NULL)
  {
    printf("Can't open input data file\n");
    exit(0);
  }

  // Open file for write output data
  fpOut = fopen(".\\data\\output.pcm", "wb");

  // Clear delay lines
  for(i=0; i<SECTIONS; i++)
  {
    for(j=0; j<3; j++)
    {
      w[i][j]= 0;
    }
  }

  // Get coefficients b[][] from NUM[][]
  for(k=0, i=0; i<SECTIONS; i++)
  {
    gain = NUM[k++][0];
    for(j=0; j<3; j++)
    {
      t32 = (long)gain * NUM[k][j];
      b[i][j]= (short)(t32>>14);
    }
    k++;
  }
  // Get coefficients a[][] from DEN[][]
  for(k=0, i=0; i<SECTIONS; i++)
  {
    gain = DEN[k++][0];
    for(j=0; j<3; j++)
    {
      t32 = (long)gain * DEN[k][j];
      a[i][j]= (short)(t32>>14);
    }
    k++;
  }

  // Filter test
  while (fread(temp, sizeof(char), 2, fpIn) == 2)
  {
    in = (temp[0]&0xFF)|(temp[1]<<8);

    // Filter the data
    cascadeIIR(in, w, &y, b, a, SECTIONS);

    temp[0] = (y&0xFF);
    temp[1] = (y>>8)&0xFF;
    fwrite(temp, sizeof(char), 2, fpOut);
  }

  fclose(fpIn);
  fclose(fpOut);
}