# Wavelet Transfrom + Power Spectral Density (using Matlab)

I don't have background knowledge about signal processing before and new at Matlab too.

I have EEG data (with noise removed) 1x128; sampling rate = 128 Hz, It's means that I have 1 sec. data right?

OK, I need to extracted to 5 frequency bands that are Delta (0-4 Hz), Theta (4-8 Hz), Alpha (8-16 Hz), Beta (16- 32 Hz) and Gamma (32-64 Hz) by Wavelet Transform (using Matlab), What is/are function--commands should I use?

And then, I need to compute the power spectrum (PSD) for each band, What is/are function--commands should I use?

Example:

Input: X = [1:128] and I need
Output: Y = [psdOfDelta, psdOfTheta, psdOfAlpha, psdOfBeta, psdOfGamma]


Thanks.

• i have the same problem and i do not know how to use wavelet or FFT to get power spectrum density, so please i need help. – user7854 Feb 10 '14 at 17:12
• @shereen I used this method mathworks.com/matlabcentral/answers/… – 1407522 Mar 10 '14 at 17:03

## 1 Answer

You need to do 1-Dimensional wavelet package decomposition. Here is the matlab documentation for the command to do this.

Here is some example code based on what you've described above:

wpt = wpdec(X, 2, 'db1', 'shannon')
plot(wpt)


This will provide a nice clickable graph. As you'll see in the documentation, you can provide a lot of different parameters for the decomposition.