[Tftb-help] Help, why 'morlet' and 'a' expressions are of this form in tfrscalo?

[ting xu]

Greetings all,

I am trying to use wavelet method to analyze the brain signal. I found the results from 'tfrscalo' and 'cwt' were different. It is difficult for me to understand the following questions:

(1) In tfrscalo, the script showed that the morlet wavelet was generated by ha  = exp(-(2*log(10)/nha^2)*tha.^2).*exp(i*2*pi*f(ptr)*tha). Should the morlet be exp(-x^2/2)*cos(5*x)?

(2) the scale 'a' and the frequency 'f' have a relationship f=fc*fs/a, here fc is the center frequency of a wavelet, fs is the sampling frequency. But in tfrscalo, f = logspace(log10(fmin),log10(fmax),N), a = logspace(log10(fmax/fmin),log10(1),N), it does not seem to satisfy f=fc*fs/a. I have confused about it.

  

Can anyone help me please? Much appreciate!

 

Best regards,
Ting Xu

--
Xu,Ting
Postgraduate
Neuropsychology and Applied Cognitive Neuroscience (NACN) Lab
Institute of Psychology
Chinese Academy of Sciences
Beijing 100101
China