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wavelet spectra help [message #10047]

Mon, 06 October 1997 00:00

rickeym
Messages: 6
Registered: September 1997

Junior Member

The matlab wavelet toolbox documentation and examples do not describe
how to form wavelet spectra from a time series. The way I do spectra
using the wavelet toolbox is as follows:

1. I call cwt.m to get the wavelet coefficients.

2. I then form a new matrix of abs(coefs)^2 to get the wavelet energy
density at a given location in wavelet space.

3. I use the morlet wavelet, so i can find the frequency = 1./scale.
Where scale is returned by cwt.m.

4. If a contour plot is made of the wavelet energy density, where the x
axis is time and the y axis is frequency, the plot indicates wavelet
energy density as a function of freq and time.

5. If I take a vertical cut through the plot in part 4, and plot wavelet
energy density (y axis) versus frequency (x axis) does this represent a
local spectra?

Is the above procedure esentially correct? Does anyone have any IDL code
to check these results? Any suggestions greatly appreciated.
Thanks!

Rick McDaniel

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wavelet spectra help

By: rickeym on Mon, 06 October 1997 00:00

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