How to use Wavelet in my dataset?

Hi Matlab users,

I am new in using Matlab Morlet wavelet function and not quite sure if I am in the right track! I have a EEG dataset (1x30720) as EEG data, I want to use "morlet" function in Matlab to extract the frequency power in time domain. I checked the "help morlet" in Matlab but did not help much. As far as I know I should obtain the wavelet function "PSI" using "morlet" and then convolute that with my EEG data in time-domain. Is that correct? How can I define the length of window in morlet? I need bigger window for low frequencies compared to high frequencies.

I really much appreciate any hint.

Best, Mehdi...