private void buildCriticalBandFilterbank()
{
int num = (this.numberFftPoints >> 1) + 1;
FrequencyWarper frequencyWarper = new FrequencyWarper();
this.criticalBandFilter = new PLPFilter[this.numberFilters];
if (this.numberFftPoints == 0)
{
string text = "Number of FFT points is zero";
throw new IllegalArgumentException(text);
}
if (this.numberFilters < 1)
{
string text2 = new StringBuilder().append("Number of filters illegal: ").append(this.numberFilters).toString();
throw new IllegalArgumentException(text2);
}
double[] array = new double[num];
double num2 = (double)(this.sampleRate / 2);
for (int i = 0; i < num; i++)
{
array[i] = (double)i * num2 / (double)(num - 1);
}
double num3 = frequencyWarper.hertzToBark(this.minFreq);
double num4 = frequencyWarper.hertzToBark(this.maxFreq);
if (this.numberFilters < 1)
{
string text3 = new StringBuilder().append("Number of filters illegal: ").append(this.numberFilters).toString();
throw new IllegalArgumentException(text3);
}
double num5 = (num4 - num3) / (double)(this.numberFilters + 1);
for (int i = 0; i < this.numberFilters; i++)
{
double centerFreqInHz = frequencyWarper.barkToHertz(num3 + (double)i * num5);
this.criticalBandFilter[i] = new PLPFilter(array, centerFreqInHz);
}
}
public PLPFilter(double[] DFTFrequenciesInHz, double centerFreqInHz)
{
FrequencyWarper frequencyWarper = new FrequencyWarper();
this.numDFTPoints = DFTFrequenciesInHz.Length;
this.__centerFreqInHz = centerFreqInHz;
this.__centerFreqInBark = frequencyWarper.hertzToBark(centerFreqInHz);
if (centerFreqInHz < DFTFrequenciesInHz[0] || centerFreqInHz > DFTFrequenciesInHz[this.numDFTPoints - 1])
{
string text = "Center frequency for PLP filter out of range";
throw new IllegalArgumentException(text);
}
this.filterCoefficients = new double[this.numDFTPoints];
for (int i = 0; i < this.numDFTPoints; i++)
{
double num = frequencyWarper.hertzToBark(DFTFrequenciesInHz[i]) - this.__centerFreqInBark;
if (num < -2.5)
{
this.filterCoefficients[i] = (double)0f;
}
else if (num <= -0.5)
{
this.filterCoefficients[i] = Math.pow(10.0, num + 0.5);
}
else if (num <= 0.5)
{
this.filterCoefficients[i] = (double)1f;
}
else if (num <= 1.3)
{
this.filterCoefficients[i] = Math.pow(10.0, -2.5 * (num - 0.5));
}
else
{
this.filterCoefficients[i] = (double)0f;
}
}
}