Package com.nr.test.test_chapter13

Source Code of com.nr.test.test_chapter13.Test_Hann

package com.nr.test.test_chapter13;

import static java.lang.Math.abs;
import static java.lang.Math.acos;
import static java.lang.Math.cos;
import static org.junit.Assert.fail;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.nr.sp.Hann;
import com.nr.sp.Spectreg;

public class Test_Hann {

  @Before
  public void setUp() throws Exception {
  }

  @After
  public void tearDown() throws Exception {
  }

  @Test
  public void test() {
    double maxf=0,maxs,pi=acos(-1.0),sbeps;;
    int i,j,maxi=0,M=128,N=2*M,K=64;
    double[] data= new double[N],spec=new double[(M+1)],freq=new double[(M+1)];
    boolean localflag, globalflag=false;

   

    // Test Hann
    System.out.println("Testing Hann");

    Spectreg sp=new Spectreg(M);
    Hann hann = new Hann(N);

    for (i=0;i<K;i++) {
      // Generate a data set
      for (j=0;j<N;j++)
        data[j]=cos(2.0*pi*64*j/N);
      sp.adddataseg(data,hann);
    }
    spec=sp.spectrum();
    freq=sp.frequencies();
//    for (i=0;i<M+1;i++)
//      System.out.printf(freq[i] << " " << spec[i]);

    maxs=-1.0;
    for (i=0;i<M+1;i++) {
      if (spec[i] > maxs) {
        maxf=freq[i];
        maxs=spec[i];
        maxi=i;
      }
    }

    sbeps=1.e-15;
    localflag=abs(maxf-0.25) > sbeps;
    globalflag = globalflag || localflag;
    if (localflag) {
      fail("*** Hann: Spectrum maximum is at wrong frequency");
     
    }

    sbeps=1.e-5;
    localflag = false;
    for (i=2;i<10;i++) {
//      System.out.printf(spec[maxi+i]/maxs << " " << spec[maxi-i]/maxs);
      localflag = localflag || (spec[maxi+i]/maxs > sbeps);
      localflag = localflag || (spec[maxi-i]/maxs > sbeps);
    }
    globalflag = globalflag || localflag;
    if (localflag) {
      fail("*** Hann: Channels adjacent to maximum (starting at second) should be zero for Hann window");
     
    }
   
    Spectreg sp2=new Spectreg(M);

    for (i=0;i<K;i++) {
      // Generate a data set offset by 1/2 channel in frequency
      for (j=0;j<N;j++)
        data[j]=cos(2.0*pi*64.5*j/N);
      sp2.adddataseg(data,hann);
    }
    spec=sp2.spectrum();
    freq=sp2.frequencies();
//    for (i=0;i<10;i++)
//      System.out.printf(spec[maxi-i]/maxs << " " << spec[maxi+i+1]/maxs);

    // test for symmetry
    sbeps=1.e-2;
    localflag=false;
    for (i=0;i<5;i++) {
      localflag = localflag || abs(spec[maxi-i]/spec[maxi+i+1]-1.0) > sbeps;
//      System.out.printf(abs(spec[maxi-i]/spec[maxi+i+1]-1.0));
    }
    globalflag = globalflag || localflag;
    if (localflag) {
      fail("*** Hann: Sidelobes are not symmetrical");
     
    }

    // test for amplitude
    double expect[]={1.0,4.13485998645e-2,8.35268789403e-4,
      9.25756611431e-5,1.90930443642e-5,5.52596048088e-6};
    sbeps=1.e-6;
    for (i=0;i<6;i++) {
//      System.out.printf(setprecision(15) << spec[maxi-i]/spec[maxi]);
      localflag = abs(spec[maxi-i]/spec[maxi]/expect[i]-1.0) > sbeps;
      globalflag = globalflag || localflag;
      if (localflag) {
        fail("*** Hann: Sidelobes are not in correct proportion");
       
      }
    }

    if (globalflag) System.out.println("Failed\n");
    else System.out.println("Passed\n");
  }

}
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