/*
* Computes the discrete Fourier transform (DFT) of the given vector.
* All the array arguments must have the same length.
*/
public static ImaginaryNumber[] computeDft(ImaginaryNumber[] signal)
{
int n = signal.Length;
ImaginaryNumber[] dftResult = new ImaginaryNumber[n];
for(int i = 0; i < dftResult.Length; i++)
{
dftResult[i] = new ImaginaryNumber(0, 0);
}
for (int k = 0; k < n; k++)
{ // For each output element
double sumreal = 0;
double sumimag = 0;
for (int t = 0; t < n; t++)
{ // For each input element
double angle = 2 * Math.PI * t * k / n;
sumreal += signal[t].Real * Math.Cos(angle) + signal[t].Img * Math.Sin(angle);
sumimag += -signal[t].Real * Math.Sin(angle) + signal[t].Img * Math.Cos(angle);
}
dftResult[k].Real = (float)sumreal;
dftResult[k].Img = (float)sumimag;
}
return dftResult;
}
static void Main(string[] args)
{
string[] lines = System.IO.File.ReadAllLines(@"C:\Users\IngMarIntern\Desktop\Signal_IN.txt");
StreamWriter FrequencyRFileWriter = new StreamWriter("C:\\Users\\IngMarIntern\\Desktop\\Freq_R.txt", false);
StreamWriter FrequencyIFileWriter = new StreamWriter("C:\\Users\\IngMarIntern\\Desktop\\Freq_I.txt", false);
ImaginaryNumber[] signalValues = new ImaginaryNumber[lines.Length/2];
ImaginaryNumber[] dftValues = new ImaginaryNumber[lines.Length/2];
for(int i = 0; i < lines.Length/2; i++)
{
signalValues[i] = new ImaginaryNumber((float)double.Parse(lines[i]), 0);
}
dftValues = DFTCalculator.computeDft(signalValues);
foreach(ImaginaryNumber i in dftValues)
{
FrequencyRFileWriter.WriteLine(i.Real.ToString());
FrequencyIFileWriter.WriteLine(i.Img.ToString());
}
}
