Re: [Tftb-help] tfrscalo help

[Eric Chassande-Mottin]

> "2 * log (10)" in    ha =
> exp(-(2*log(10)/nha^2)*tha.^2).*exp(i*2*pi*f(ptr)*tha)
>
>
>
> in the tfrscalo function.
>
> Why not simply   ha = exp (-tha. ^2 /nha^2).*exp (i*2*pi*f (ptr)*tha)?

hi,

I think this makes the wavelet approximately zero mean.
(i.e., integral ha(t) dt ~ 0). this property ensures
that the underlying wavelet transform (= wavelet coefficients
before taking the square modulus to get the scalogram) is
invertible. for a discussion, Flandrin "Temps-frequence"
Hermes, p 83 sec 223 Des exemples temps-echelle.

cheers,
eric