public void TestComputePSD(int fs, int N, double Nw, double Nover, int Nzp, DetectorWindowType windowtype, double expValue00, double expValue10, double expValue0e, double expValue1e, double expValue0m, double expValue1m)
{
List <List <double> > dataInFreqDomain;
List <double> freqAll;
Functions.ComputePSD(data, fs, N, Nw, Nover, Nzp, windowtype, out dataInFreqDomain, out freqAll);
var slength = dataInFreqDomain[0].Count;
NUnit.Framework.Assert.AreEqual(dataInFreqDomain.Count, 2);
NUnit.Framework.Assert.AreEqual(slength, 1500);
NUnit.Framework.Assert.AreEqual(dataInFreqDomain[0][0], expValue00);
NUnit.Framework.Assert.AreEqual(dataInFreqDomain[1][0], expValue10);
NUnit.Framework.Assert.AreEqual(dataInFreqDomain[0][slength - 1], expValue0e);
NUnit.Framework.Assert.AreEqual(dataInFreqDomain[1][slength - 1], expValue1e);
NUnit.Framework.Assert.AreEqual(dataInFreqDomain[0][slength / 2], expValue0m);
NUnit.Framework.Assert.AreEqual(dataInFreqDomain[1][slength / 2], expValue1m);
NUnit.Framework.Assert.AreEqual(freqAll.Count, 1500);
NUnit.Framework.Assert.AreEqual(freqAll[0], 0);
NUnit.Framework.Assert.AreEqual(freqAll[freqAll.Count - 1], 29.98);
NUnit.Framework.Assert.AreEqual(freqAll[freqAll.Count / 2], 15);
}
public void TestInspectionSpectral(double analysisLength, double windowLength, DetectorWindowType windowType, double windowOverlap, int zeroPadding, int fs, bool logScale, double freqMin, double freqMax, string expectedResults)
{
var parameters = new InspectionAnalysisParameters();
parameters.AnalysisLength = analysisLength;
parameters.WindowLength = windowLength;
parameters.WindowType = windowType;
parameters.WindowOverlap = windowOverlap;
parameters.ZeroPadding = zeroPadding;
parameters.Fs = fs;
parameters.LogScale = logScale;
parameters.FreqMax = freqMax;
parameters.FreqMin = freqMin;
var result = Functions.InspectionSpectral(data, parameters);
NUnit.Framework.Assert.AreEqual(result.X.Count, 46);
NUnit.Framework.Assert.AreEqual(result.Y.Count, 2);
NUnit.Framework.Assert.AreEqual(result.Y[0].Count, 46);
NUnit.Framework.Assert.AreEqual(result.Ylabel, expectedResults);
NUnit.Framework.Assert.AreEqual(result.Xlabel, "F (Hz)");
}
public static void ComputePSD(List <List <double> > data, int fs, int N, double Nw, double Nover, int Nzp, DetectorWindowType windowtype, out List <List <double> > dataInFreqDomain, out List <double> freqAll)
{
double[] win;
switch (windowtype)
{
case Core.Models.DetectorWindowType.hann:
win = Window.Hann((int)Nw);
break;
case Core.Models.DetectorWindowType.rectwin:
win = _rectwin((int)Nw);
break;
case Core.Models.DetectorWindowType.bartlett:
win = Window.Bartlett((int)Nw);
break;
case Core.Models.DetectorWindowType.hamming:
win = Window.Hamming((int)Nw);
break;
case Core.Models.DetectorWindowType.blackman:
win = Window.Blackman((int)Nw);
break;
default:
throw new Exception(windowtype.ToString() + " is not an acceptable window type.");
}
var U = win.Sum(x => Math.Pow(x, 2));
dataInFreqDomain = new List <List <double> >();
//find the frequency vector which should be the x axis of the spectrum
freqAll = new List <double>();
for (int i = 0; i < Nzp; i++)
{
freqAll.Add((double)fs * i / Nzp);
}
//comput the number of segments: (signalLength - overlap)/(windowLength - overlap)
//round towards zero
var M = Math.Floor((N - Nover) / (Nw - Nover));
foreach (var sig in data)
{
var newSig = new List <double>();
var dat = sig.GetRange(0, N);
var mean = dat.Average();
foreach (var p in dat)
{
var pp = p - mean;
newSig.Add(pp);
}
double[] Pxx = null;
for (int i = 0; i < M; i++)
{
var start = (int)(i * (Nw - Nover));
var end = (int)(i * (Nw - Nover) + Nw);
//Console.WriteLine("start from " + start.ToString() + ", end at " + end.ToString());
//to match InspectionSpectral where mean is removed before calling pwelch
var frag = newSig.GetRange(start, (int)Nw);
//to match CalcPSD_OmegaB.m where mean is not removed from the data before calling fft
//var frag = dat.GetRange(start, (int)Nw);
//Console.WriteLine("number of point " + frag.Count());
//double[] real = null;
var fragcount = frag.Count;
//if (fragcount % 2 == 0)
//{
// real = new double[fragcount + 2];
// real[fragcount] = 0d;
// real[fragcount + 1] = 0d;
//}
//else
//{
// real = new double[fragcount + 1];
// real[fragcount] = 0d;
//}
var complex = new Complex[Nzp];
//multiply with filter win first
for (int ii = 0; ii < frag.Count; ii++)
{
//real[ii] = frag[ii] * win[ii];
complex[ii] = new Complex(frag[ii] * win[ii], 0);
}
//might need an empty vector to hold results, or pass by ref?
//Console.WriteLine(frag[0]);
//var fragarray = frag.ToArray();
//Console.WriteLine("[{0}]", string.Join(", ", real));
//Fourier.ForwardReal(real, fragcount, FourierOptions.Matlab);
//Console.WriteLine("[{0}]", string.Join(", ", real));
//Console.WriteLine("[{0}]", string.Join(", ", complex));
Fourier.Forward(complex, FourierOptions.Matlab);
//Console.WriteLine("[{0}]", string.Join(", ", complex));
//Console.WriteLine("real: {0}, imaginary: {1}, magnitude: {2}", complex[0].Real, complex[0].Imaginary, complex[0].Magnitude);
if (Pxx == null)
{
Pxx = new double[complex.Length];
}
for (int ii = 0; ii < complex.Length; ii++)
{
Pxx[ii] = Pxx[ii] + (Math.Pow(complex[ii].Magnitude, 2) / (U * M));
}
}
//Pxx[0] = Pxx[0] / 2;
dataInFreqDomain.Add(Pxx.ToList());
}
}
