floatpoint_directiirtest.c

来自「CHP 5 - Real-Time Digital Signal Process」· C语言 代码 · 共 81 行

// 
//  Project: Experiment 5.7.1: implementation of floating-point IIR filter in direct form I - Chapter 5
//  File name: floatPoint_directIIRTest.c   
//
//  Description: This is the test file for the floating-point direct form I IIR filter
//
//  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 "floatPointIIR.h"

// Coefficient length
#define NL  13
#define DL  13

// Filter coefficients obtained from example 5.12 MATLAB script
double num[NL] = {0.0039, 0.0000, 0.0028, 0.0000, 0.0074, 0.0000,
                  0.0025, 0.0000, 0.0074, 0.0000, 0.0028, 0.0000, 0.0039};

double den[DL] = {1.0000, 0.0000, 4.2912, 0.0000, 8.2629, 0.0000,
                  8.9932, 0.0000, 5.7991, 0.0000, 2.0930, 0.0000, 0.3300};

// Filter delay lines
double x[NL],y[DL];

void main()
{
  double in;
  short  i,z;
  FILE   *fpIn,*fpOut;
  char   temp[2];

  // Open file for read input data
  if ((fpIn = fopen("..\\data\\input.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<NL; i++)
  {
    x[i] = 0.0;
  }
  for(i=0; i<DL; i++)
  {
    y[i] = 0.0;
  }

  // Filter test
  while (fread(temp, sizeof(char), 2, fpIn) == 2)
  {
    // Convert 16-bit PCM data to floating-point format
    z = (temp[0]&0xFF)|(temp[1]<<8);
    in = (double)z/32767.0;

    // Filter the data
    floatPoint_IIR(in, x, y, num, NL, den, DL);

    // Convert the floating-point data back to 16-bit PCM data format
    z = (short)(y[0]*32767.0 + 0.5);
    temp[0] = (z&0xFF);
    temp[1] = (z>>8)&0xFF;
    fwrite(temp, sizeof(char), 2, fpOut);
  }
  
  fclose(fpIn);
  fclose(fpOut);
}