Fast Fourier Transform in C#

Question

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Fast fourier transform in c#

I am looking for an example of performing a real time FFT (Fast Fourier Transform) of line in or mic audio data in C#. My goal is to determine in real time if a particular note is present in the audio data. Any examples appreciated.

Answer 1

AForge.NET is an open-source library with Fast Fourier Transform support.
ExocortexDSP is also another option.

ExocortexDSP example would look something like this:

   Exocortex.DSP.ComplexF[] complexData = new Exocortex.DSP.ComplexF[512];
   for (int i = 0; i < 512; ++i)
   {
      // Fill the complex data
      complexData[i].Re = 1; // Add your real part here
      complexData[i].Im = 2; // Add your imaginary part here
   }

   // FFT the time domain data to get frequency domain data
   Exocortex.DSP.Fourier.FFT(complexData, Exocortex.DSP.FourierDirection.Forward);

   float[] mag_dat_buffer = new float[complexData.Length];
   // Loop through FFT'ed data and do something with it
   for (int i = 0; i < complexData.Length; ++i)
   {
      // Calculate magnitude or do something with the new complex data
      mag_data_buffer[i] = ImaginaryNumberMagnitude(complexData[i].Im, complexData[i].Re);
   }