// Test welch
System.out.println("Testing welch");
WelchWin welch = new WelchWin();
Spectreg sp = new Spectreg(M);
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,welch);
}
spec=sp.spectrum();
freq=sp.frequencies();
// for (i=0;i<M+1;i++)
// System.out.printf(freq[i] << " %f\n", 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("*** welch: Spectrum maximum is at wrong frequency");
}
// Test symmetry
sbeps=1.e-12;
localflag = false;
for (i=1;i<10;i++) {
// System.out.printf(abs(spec[maxi+i]/spec[maxi-i]-1.0));
localflag = localflag || abs(spec[maxi+i]/spec[maxi-i]-1.0) > sbeps;
}
globalflag = globalflag || localflag;
if (localflag) {
fail("*** welch: Channels adjacent to maximum should be symmetrical");
}
// Test amplitudes
sbeps=1.e-2;
localflag = false;
for (i=2;i<6;i++) {
// System.out.printf(abs(spec[maxi+i]/spec[maxi+1]*SQR(SQR(i))-1.0));
localflag = localflag || abs(spec[maxi+i]/spec[maxi+1]*SQR(SQR(i))-1.0) > sbeps;
globalflag = globalflag || localflag;
if (localflag) {
fail("*** welch: Sidelobe amplitudes are not in the correct proportion");
}
}
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,welch);
}
spec=sp2.spectrum();
freq=sp2.frequencies();
// for (i=0;i<10;i++)
// System.out.printf(spec[maxi-i]/maxs << " %f\n", spec[maxi+i+1]/maxs);
sbeps=5.e-3;
localflag=false;