# Apply wavelet transform to analyse EEG signal

I would like to apply The Morlet wavelet transform to analyse my EEG signals. I have many short signals each is only 1 min long. and they all recorded in 30Hz. I have Two questions:

1. In the Morlet wavelet, What is the best scale (alpha) to use in my case ?
2. About the edge effect: How can I know / compute what portion of my data will be corrupted due to the wavelet "edge effect" ?
• + please forgive me that I am not a native English speaker :) – Dov Dec 16 '11 at 9:27
• Also consider the complex Morlet wavelet, which I know is used in EEG stuff. It matches at any phase, like STFT. flic.kr/p/7oXfbT flic.kr/p/7oXfh6 – endolith Dec 16 '11 at 15:10

I'm not sure whether you're talking about Discrete Wavelet Transform (DWT) or Continuous Wavelet Transform (CWT). Both can be used on discrete signals similarly to DFT and DTFT, I'm not sure if anyone calls it the Discrete Time Wavelet Transform instead. In any case, the dyadic wavelet transform is the non-redundant one (number of samples in $=$ number of coefficients out), and that's what we usually assume by talking about DWT.