static LinkedList <FrequencyMagnitude> DFT(string filePath, string ouputDirectoryPath)
{
var inputSamplesList = CSVUtils.ReadCSVFile <CSVWaveRecord>(filePath);
if (ZeroPadDFT)
{
Utils.PadWithZeros(inputSamplesList);
}
var frequencyResolution = Utils.CalculateFrequencyResolution(inputSamplesList);
var inputSamplesArray = inputSamplesList.Select(x => new Complex((double)x.Volts, 0)).ToArray();
var dftValues = FourierTransforms.DiscreteFourierTransform(inputSamplesArray);
inputSamplesArray = null;
var size = dftValues.Length / 2;
var leftHalfArray = new Complex[size];
Array.Copy(dftValues, leftHalfArray, size);
dftValues = null;
var intermediateFile = Path.Combine(ouputDirectoryPath,
Path.GetFileName(filePath).Replace("Wave", "DFT"));
Utils.printOutput(leftHalfArray, frequencyResolution, intermediateFile);
return(Utils.GetFrequencyDomain(leftHalfArray, frequencyResolution));
}
public void Test_FFT_VS_DFT()
{
var csvFilePath = Path.Combine(
TestContext.CurrentContext.TestDirectory,
@"TestData\Wave000.csv");
var inputSamplesList = CSVUtils.ReadCSVFile <CSVWaveRecord>(csvFilePath);
var dftInputArray = inputSamplesList.Select(x => new Complex((double)x.Volts, 0)).ToArray();
Utils.PadWithZeros(inputSamplesList);
var fftInputArray = inputSamplesList.Select(x => new Complex((double)x.Volts, 0)).ToArray();
FourierTransforms.DiscreteFourierTransform(dftInputArray);
FourierTransforms.FastFourierTransform(fftInputArray, 0, fftInputArray.Length);
}
public void Test_WaveFormIntervals()
{
var csvFilePath = Path.Combine(
TestContext.CurrentContext.TestDirectory,
@"TestData\Wave000.csv");
var inputSamplesList = CSVUtils.ReadCSVFile <CSVWaveRecord>(csvFilePath);
var seconds = inputSamplesList.Select(x => x.Seconds).ToArray();
var diffList = new LinkedList <decimal>();
for (int i = 1; i < seconds.Length; i++)
{
var diff = seconds[i] - seconds[i - 1];
diffList.AddLast(diff);
}
Assert.IsTrue(diffList.All(x => x >= 6E-8m && x <= 6.1E-8m));
}