MATLAB: I need to plot the EEG in matlab.. i have downloaded the data base which is in .txt format. bt i am unable to plot it.. plz help

eeg plot

x=load('F001.txt'); 
y=fft(x)
PS=abs(y).^2;
N=length(x);
fs=1000; 
freq=(1:N/2)*fs/N;
plot(freq,PS)

this is not working,… an error is reported

Error using plot Vectors must be the same lengths.

Error in PLOT (line 7) plot(freq,PS)

Best Answer

Look at freq=(1:N/2)*fs/N ,its length is different from PS length

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MATLAB: Needed FRequency analysis of an EEG signal

to be more clear

x=load('EEG_data.txt'); y=fft(x); PS=abs(y).^2; N=length(x); fs=1000; freq=(1:N/2)*fs/N; plot(freq,PS)

MATLAB: Extracting the fundamental frequency of a .wav file

Here is an example you can modify with your input y

For even length y:

    Fs = 1000;
    t = 0:0.001:1-0.001;
    y = cos(2*pi*100*t)+randn(size(t));
    ydft = fft(y);
    freq = 0:Fs/length(y):Fs/2;
    ydft = ydft(1:length(y)/2+1);
    plot(freq,abs(ydft))
    [maxval,idx] = max(abs(ydft));
    freq(idx)  %this is frequency corresponding to max value

For odd length y

    t = 0:0.001:1;
    y = cos(2*pi*100*t)+randn(size(t));
    ydft = fft(y);
    freq = 0:Fs/length(y):Fs/2;
    ydft = ydft(1:floor(length(y)/2)+1);
    [maxval,idx] = max(abs(ydft));
    freq(idx)  %this is frequency corresponding to max value

Best Answer

Related Solutions

MATLAB: Needed FRequency analysis of an EEG signal

MATLAB: Extracting the fundamental frequency of a .wav file

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