how can I find destiny power spectrum using the pwelch function?

I want to find the destiny power spectrum of my EEG signal that I filtered using Butterworth. I want to find it using the pwelch function, can you help me?

My EEG signal has fs = 512Hz, t = 600s, data length = 307200.

Answer 1

[Asvin Kumar]

I am unsure what issue you are facing with the pwelch function. Here is an example from the documentation to get you started:

https://www.mathworks.com/help/signal/ref/pwelch.html#btulru8-5

This is a bit out of my field here to suggest constants and anyone can improve upon my suggestion. I would suggest you try these out to get started:

[pxx,f] = pwelch(x, 128, 64, 128, fs); % x is your EEG signal 

fs/N is the frequency resolution of your Frequency Transform where N is the window length. It is noted in literature that the Delta waves of EEG signals have a frequency of about 3 Hz assuming that is what you want to measure. It is also often considered that having the window length to be the same as the no. of points in the Fourier Transform is helpful and so is keeping the overlap length to be half the window length.

Hope this helps!