private void Initialize(float sampleRate, int windowSize, int numberCoefficients, bool useFirstCoefficient, double minFreq, double maxFreq, int numberFilters)
{
//check for correct window size
if(windowSize < 32)
{
throw new Exception("window size must be at least 32");
}
else
{
int i = 32;
while(i < windowSize && i < Int32.MaxValue)
i = i << 1;
if(i != windowSize)
throw new Exception("window size must be 2^n");
}
//check sample rate
sampleRate = (float)Math.Round(sampleRate);
if(sampleRate < 1)
throw new Exception("sample rate must be at least 1");
//check numberFilters
if(numberFilters < 2 || numberFilters > (windowSize/2) + 1)
throw new Exception("number filters must be at least 2 and smaller than the nyquist frequency");
//check numberCoefficients
if(numberCoefficients < 1 || numberCoefficients >= numberFilters)
throw new Exception("the number of coefficients must be greater or equal to 1 and samller than the number of filters");
//check minFreq/maxFreq
if(minFreq <= 0 || minFreq > maxFreq || maxFreq > 88200.0f)
throw new Exception("the min. frequency must be greater 0 smaller than the max. frequency, which must be smaller than 88200.0");;
this.sampleRate = sampleRate;
this.windowSize = windowSize;
this.hopSize = windowSize/2; //50% Overleap
this.baseFreq = sampleRate/windowSize;
this.numberCoefficients = numberCoefficients;
this.useFirstCoefficient = useFirstCoefficient;
this.minFreq = minFreq;
this.maxFreq = maxFreq;
this.numberFilters = numberFilters;
//create buffers
inputData = new double[windowSize];
buffer = new double[windowSize];
//store filter weights and DCT matrix due to performance reason
melFilterBanks = GetMelFilterBanks();
dctMatrix = GetDCTMatrix();
//create power fft object
normalizedPowerFFT = new FFT(FFT.FFT_NORMALIZED_POWER, windowSize, FFT.WND_HANNING);
}