Using Matlab FFT to extract frequencies from EEG signal

fft, frequency, matlab

Solution

For convenient analysis of EEG data with MatLab you might consider to use the EEGLAB toolbox (http://sccn.ucsd.edu/eeglab/) or the fieldtrip toolbox (http://fieldtrip.fcdonders.nl/start).

Both toolboxes come with good tutorials:

http://sccn.ucsd.edu/eeglab/eeglabtut.html

http://fieldtrip.fcdonders.nl/tutorial

Problem

I am new to BCI. I have a Mindset EEG device from Neurosky and I record the Raw data values coming from the device in a csv file. I can read and extract the data from the csv into Matlab and I apply FFT. I now need to extract certain frequencies (Alpha, Beta, Theta, Gamma) from the FFT. Where Delta = 1-3 Hz Theta= 4-7 Hz Alpha = 8-12 Hz Beta = 13-30 Hz Gamma = 31-40 Hz This is what I did so far: ``` f = (0:N-1)*(Fs/N); plot(rawDouble); title ('Raw Signal'); p = abs(fft(rawDouble)); figure,plot (f,p); title('Magnitude of FFT of Raw Signal'); ``` Can anyone tell me how to extract those particular frequency ranges from the signal?? Thank you very much!

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