public static double[] getSinc(int sampleRate, long frequency, int length, WindowType window)
{
//Get unity response array (one element longer to align with IDFT size)
double[] frequencyResponse = getUnityResponseArray(sampleRate, frequency, length + 1);
//Apply Inverse DFT against frequency response unity values, leaving the
//IDFT bin results in the frequency response array
FFTHelper idft = new FFTHelper();
idft.RealFFT(frequencyResponse, false);
/*
* DoubleFFT_1D idft = new DoubleFFT_1D(length + 1);
* idft.realInverseFull(frequencyResponse, false);
*/
//Transfer the IDFT results to the return array
double[] coefficients = new double[length];
int middleCoefficient = (int)(length / 2);
//Bin 0 of the idft is our center coefficient
coefficients[middleCoefficient] = frequencyResponse[0];
//The remaining idft bins from 1 to (middle - 1) are the mirror image
//coefficients
for (int x = 1; x < middleCoefficient; x++)
{
coefficients[middleCoefficient + x] = frequencyResponse[2 * x];
coefficients[middleCoefficient - x] = frequencyResponse[2 * x];
}
//Apply the window against the coefficients
coefficients = Window.apply(window, coefficients);
//Normalize to unity (1) gain
coefficients = normalize(coefficients);
return(coefficients);
}
public static double[] getSinc(int sampleRate, long frequency, int length, WindowType window)
{
//Get unity response array (one element longer to align with IDFT size)
double[] frequencyResponse = getUnityResponseArray(sampleRate, frequency, length + 1);
//Apply Inverse DFT against frequency response unity values, leaving the
//IDFT bin results in the frequency response array
FFTHelper idft = new FFTHelper();
idft.RealFFT(frequencyResponse, false);
/*
DoubleFFT_1D idft = new DoubleFFT_1D(length + 1);
idft.realInverseFull(frequencyResponse, false);
*/
//Transfer the IDFT results to the return array
double[] coefficients = new double[length];
int middleCoefficient = (int)(length / 2);
//Bin 0 of the idft is our center coefficient
coefficients[middleCoefficient] = frequencyResponse[0];
//The remaining idft bins from 1 to (middle - 1) are the mirror image
//coefficients
for (int x = 1; x < middleCoefficient; x++)
{
coefficients[middleCoefficient + x] = frequencyResponse[2 * x];
coefficients[middleCoefficient - x] = frequencyResponse[2 * x];
}
//Apply the window against the coefficients
coefficients = Window.apply(window, coefficients);
//Normalize to unity (1) gain
coefficients = normalize(coefficients);
return coefficients;
}
