Re: filter raw EEG by frequency bands in time domain

[Sergei Steshenko]

On 03/05/2020 23:09, Nicklas Karlsson wrote:
> fft transform from time domain to frequency domain, you get amplitudes for 
> different frequencies. ifft is inverse transform, guess you do not need this.


"fft transform from time domain to frequency domain, you get amplitudes 
for different frequencies. ifft is inverse transform, guess you do not 
need this." - huh ? The OP explicitly stated he needed result in time 
domain, so if FFT processing is to be used, ifft is absolutely necessary.

And specifically regarding "you get amplitudes for different 
frequencies" - it's an incomplete statement. FFT produces array of 
complex numbers from real inputs. Real part represents the 'cos' 
component of the frequency bin, and imaginary part represents the 'sin' 
component of the frequency bin.


--Sergei.