/**
* Designs the Mel filter and creates triangular spectrum.
*
* @param filterNum which filter in a sequence it is
* @param melFilterWidth filter width in Mel scale (eg. 200)
* @param N filter spectrum size (must be the same as filtered spectrum)
*/
void MelFilter::createFilter(std::size_t filterNum,
FrequencyType melFilterWidth, std::size_t N)
{
// calculate frequencies in Mel scale
FrequencyType melMinFreq = filterNum * melFilterWidth / 2.0;
FrequencyType melCenterFreq = melMinFreq + melFilterWidth / 2.0;
FrequencyType melMaxFreq = melMinFreq + melFilterWidth;
// convert frequencies to linear scale
FrequencyType minFreq = melToLinear(melMinFreq);
FrequencyType centerFreq = melToLinear(melCenterFreq);
FrequencyType maxFreq = melToLinear(melMaxFreq);
// generate filter spectrum in linear scale
generateFilterSpectrum(minFreq, centerFreq, maxFreq, N);
}
/**
* Designs the Mel filter and creates triangular spectrum.
*
* @param filterNum which filter in a sequence it is?
* @param melFilterWidth filter width in Mel scale (eg. 200)
* @param N filter spectrum size (must be the same as filtered spectrum)
*/
void MelFilter::createFilter(unsigned short filterNum,
unsigned short melFilterWidth, unsigned int N)
{
// calculating frequencies in Mel scale
double melMinFreq = filterNum * melFilterWidth / 2.0;
double melCenterFreq = melMinFreq + melFilterWidth / 2.0;
double melMaxFreq = melMinFreq + melFilterWidth;
// converting them to linear
double minFreq = melToLinear(melMinFreq);
double centerFreq = melToLinear(melCenterFreq);
double maxFreq = melToLinear(melMaxFreq);
// generating spectrum in linear scale
generateFilterSpectrum(minFreq, centerFreq, maxFreq, N);
}