/// <summary>
/// Method to handle user's selection in frequency domain
/// passes selected samples to concolution filter.
/// </summary>
/// <param name="method"></param>
public void filterSelectedFrequencies(FILTERING method = FILTERING.convolution)
{
if (freqSelStart == freqSelEnd)
{
return;
}
double[] filter = new double[fourierN];
for (int fbin = 0; fbin < filter.Length; fbin++)
{
if ((fbin >= freqSelStart && fbin <= freqSelEnd) || (fbin >= fourierN - freqSelEnd && fbin <= fourierN - freqSelStart))
{
filter[fbin] = 0;
}
else
{
filter[fbin] = 1;
}
}
double criticalPoint = 0;
if (method == FILTERING.IIRLowpass)
{
criticalPoint = freqSelStart * SampleRate / fourierN;
}
else
{
criticalPoint = freqSelEnd * SampleRate / fourierN;
}
for (int channel = 0; channel < wave.channels; channel++)
{
switch (method)
{
case FILTERING.convolution:
wave.samples[channel] = Formulas.convolveFilter(ref wave.samples[channel], filter);
break;
case FILTERING.DFT:
wave.samples[channel] = Formulas.dftFilter(wave.samples[channel], filter);
break;
case FILTERING.IIRLowpass: //low pass
wave.samples[channel] = Formulas.IIRFilter(wave.samples[channel], Math.Min(criticalPoint + 5000, SampleRate / 2), Math.Max(0, criticalPoint - 5000), 0, SampleRate);
break;
case FILTERING.IIRHighpass: //high pass
wave.samples[channel] = Formulas.IIRFilter(wave.samples[channel], Math.Max(0, criticalPoint - 7000), Math.Min(criticalPoint + 3000, SampleRate / 2), 1, SampleRate);
break;
default:
MessageBox.Show("Error occured");
break;
}
}
timeDomain.setSamples(wave.samples);
timeDomain.Invalidate();
calculateDFT();
invalidPlayer = true;
}
