private void ExportButton_Click(object sender, RoutedEventArgs e)
{
SaveFileDialog saveFileDialog = new SaveFileDialog();
saveFileDialog.Filter = $"{Properties.Resources.FILTER_IMPORT_EXPORT_FILE_EXTENSION} (*{Properties.Resources.FILTER_IMPORT_EXPORT_FILE_EXTENSION})|*{Properties.Resources.FILTER_IMPORT_EXPORT_FILE_EXTENSION}|{Properties.Resources.ALL_FILES} (*.*)|*.*";
if (saveFileDialog.ShowDialog() == true)
{
try
{
using (StreamWriter fileWriter = File.CreateText(saveFileDialog.FileName))
{
fileWriter.WriteLine(Properties.Resources.FILTER_CSV_HEADER);
List <double> summedFilterData = manager.ActiveWorkBook().CombinedFilterImpulseResponse(true);
ComplexFastFourierTransform cmplxFFT = new ComplexFastFourierTransform();
FrequencyDomain frequencyDomain = cmplxFFT.Transform(summedFilterData, manager.ActiveWorkBook().WindowedSyncFilters.Values.First().FilterLength);
var magPhaseList = ComplexFastFourierTransform.ToMagnitudePhaseList(frequencyDomain);
foreach (Tuple <double, double> coefficientMagPhase in magPhaseList)
{
fileWriter.WriteLine($"{coefficientMagPhase.Item1},{coefficientMagPhase.Item2}");
}
}
} catch (Exception ex)
{
Log.Warning(ex, ex.Message);
// TODO warn user
}
}
}
public void TestComplexTransform()
{
//IDFT complexFourierTransform = new ComplexFastFourierTransform();
IDFT complexFourierTransform = new DSPGuideComplexDiscreteFourierTransform();
FrequencyDomain result;
List <double> recreatedSignal;
int sampleRate = 1000; // hz
List <double> timePoints = new List <double>(2 * sampleRate);
for (double timePointVal = 0; timePointVal < 2.0; timePointVal += (1.0 / sampleRate))
{
timePoints.Add(timePointVal);
}
List <double> signal = new List <double>(timePoints.Count);
foreach (double timePointVal in timePoints)
{
double signalValue = (2.5 * Math.Sin(2 * Math.PI * 4 * timePointVal)) + (1.5 * Math.Sin(2 * Math.PI * 6.5 * timePointVal));
signal.Add(signalValue);
}
result = complexFourierTransform.Transform(signal, sampleRate);
List <Tuple <double, double> > magPhaseList = ComplexFastFourierTransform.ToMagnitudePhaseList(result);
FrequencyDomain fromMagPhaseList = ComplexFastFourierTransform.FromMagnitudePhaseList(magPhaseList);
for (int idx = 0; idx < result.FourierCoefficients.Count; idx++)
{
double absDifference = Complex.Abs(result.FourierCoefficients[idx] - fromMagPhaseList.FourierCoefficients[idx]);
// Check that they are close, rounding error occurs, they wont be equal
Assert.IsTrue(absDifference < 1.0E-10);
}
// This file can be viewed in Excel for plotting of hz and amplitudes
StreamWriter amplitudeFile = new StreamWriter("frequencyAmplitudes.csv");
if (amplitudeFile != null)
{
amplitudeFile.WriteLine("HZ, Amplitude");
foreach (var frequencyAmplitude in result.FrequencyAmplitudes)
{
amplitudeFile.WriteLine($"{frequencyAmplitude.Key}, {frequencyAmplitude.Value}");
}
}
amplitudeFile.Close();
recreatedSignal = complexFourierTransform.Synthesize(result);
Assert.IsNotNull(result);
Assert.IsNotNull(recreatedSignal);
//double amplitude40 = result.FrequencyAmplitudes[4.0];
//double amplitude65 = result.FrequencyAmplitudes[6.5];
//Assert.IsTrue(Math.Abs(amplitude40 - 2.5) <= MaxAmplitudeDifference);
//Assert.IsTrue(Math.Abs(amplitude65 - 1.5) <= MaxAmplitudeDifference);
double maxDifference = 0.0;
for (int idx = 0; idx < recreatedSignal.Count; idx++)
{
double calculateDifference = Math.Abs(recreatedSignal[idx] - signal[idx]);
if (maxDifference < calculateDifference)
{
maxDifference = calculateDifference;
}
}
for (int idx = 0; idx < recreatedSignal.Count; idx++)
{
double calculateDifference = Math.Abs(recreatedSignal[idx] - signal[idx]);
Assert.IsTrue(calculateDifference <= MaxSignalDifference);
}
}