Wavelet signal decomposition in Octave

Question

I want to conduct signal decomposition using wavelet transformation in Octave. And I don't know, what I should do.

I was looking for any black-box functions in Octave, but haven't found anything useful. As far as I know there is dwt function in signal package, but I have no idea how to use it. In documentation it says, that:

Function File: [u, v] = dwt (x, wname)

From documentation:
x Signal vector.
wname Wavelet name.

But when I try to use it this way, octave says

error: Invalid call to dwt.  Correct usage is:

 -- Function File: [CA CD] = dwt( X,LO_D,HI_D)

Where should I get to LO_D and HI_D coeffs? Documentation says, that these are "Coefficients of low-pass/high-pass decomposition FIR filter."

And, provided, that I will calculate the dwt on my data, what should I do next to perform the decomposition?

Alternatively, could You provide me with some information, how to perform any decomposition on a signal?

Answer 1

I would suggest the excellent Large Time/Frequency Analysis Toolbox, http://ltfat.sourceforge.net/doc/wavelets/index.php in your case.