Power spectral density of a signal

Hello I have EEG dataset in excel format with time and voltage values.I need to plot the power spectral density of the signal. I have loaded the excel file in Matlab and plotted the voltage vs time values. Now I need to calculate the power spectral density. Generally the frequency range of EEG signals between 0-30 Hz. Since I have only voltage and Time values, I do not know the frequency of my signal. I need to calculate Power spectral density Using FFT. I am including the code in matlab file and time voltage values of the signal in txt file for reference. Please suggest me.

dataset=xlsread('input signal.xlsx','sheet1','A1:B770');
t = dataset(:,1);
V = dataset(:,2);
X=[t V];
subplot(2,2,1);
plot(X(:,1), X(:,2))
xlabel ('time');
ylabel('voltage');
title('original Signal');

Answer 1

[Birdman]

I assume that your sampling is 1kHz(in practice), use the following code to see the psd of the signal:

h1=spectrum.welch;
set(h1,'Windowname','Hann');
Fs=1000;
set(h1,'OverlapPercent',66.7);
set(h1,'SegmentLength',512);
myPsd=psd(h1,X(:,2)-mean(X(:,2)),'Fs',Fs)
semilogx(myPsd.Frequencies,myPsd.Data);grid on

You will see that between 0-30Hz, your signal has peaks. Hope this helps.

[dark lion]

Can we calculate This by FFT.

Thanks

[Birdman]

Yes but for that you should refer to documentation.

https://www.mathworks.com/help/matlab/ref/fft.html