public static List <ComplexNumber> DFTIntegers(List <int> input, TypeKey.Windowing type, RIFFData riff, int binStart, int binEnd)
{
List <ComplexNumber> output = new List <ComplexNumber>();
for (int f = binStart; f < binEnd; f++)
{
double reSum = 0;
double imSum = 0;
for (int t = 0; t < input.Count; t++)
{
double weight = GetWindowing(t, input.Count, type);
double angle = (2 * Math.PI * t * f) / input.Count;
reSum += weight * input[t] * Math.Cos(angle);
imSum -= weight * input[t] * Math.Sin(angle);
}
reSum /= input.Count;
imSum /= input.Count;
ComplexNumber n = new ComplexNumber();
n.Real = reSum;
n.Imaginary = imSum;
n.SetLength();
output.Add(n);
}
return(output);
}
private static double GetWindowing(int n, int N, TypeKey.Windowing type)
{
switch (type)
{
case TypeKey.Windowing.Triangular:
int L = N - 1;
return(1 - Math.Abs((n - ((N - 1) / 2)) / (L / 2)));
case TypeKey.Windowing.Welch:
return(1 - Math.Pow((n - ((N - 1) / 2)) / ((N - 1) / 2), 2));
case TypeKey.Windowing.Sine:
return(Math.Sin((Math.PI * n) / (N - 1)));
default:
return(1);
}
}
