Wavelet Analysis

[d4545uk]

I have a signal which was taken at 50 kHz.  I want to perform wavelet analysis on this.  (I am extracting the coefficients and then using these to plot the signal again for each coefficeint, ie taking the 4th level decomposition and using this to generate the signal assuming all other coefficients are zero)

To do this I am converting the signal to an array.  However this loses the dt information.  Does this mean that the wavelet analysis is then done assuming that the time between each signal is 1 s as apposed to infact 2 * 10^-5?  If so is it possible to tell the wavelet vi somehow that the time between signals is this value?  As I want to have graphs of the signal for 25kHz - 50 kHz, 12.5kHz - 25kHz etc.

Can someone offer some guidence please?

Also is it possible to use the db01 wavelet in LabVIEW?  It didn't appear on the drop down list.  Though I will use db02 for now anyway.

Sorry if these are obvious questions but I'm a newbie!

Daniel

[SachaE]

Hi,

  do you have your analysis code so far with an example waveform I can have a look at?

Thanks

Sacha Emery
National Instruments (UK)

[SachaE]

Hi,

  sorry, forgot to say, with the wavelet analysis, all the vi's will take in a waveform in the latest add on package, so maintaining the dt. Otherwise the dt will be 1s.

Try making the polymorphic selector on the VI visible.

Thanks

Sacha Emery
National Instruments (UK)

Message Edited by SachaE on 03-22-2007 03:03 PM

[d4545uk]

I applied filters to the signal so am happy that the frequency response is what I'd like.  I create a waveform from the coefficents generated and then rescale it so I think even if it does think the dt is 1 by reconstructing the signal this way it sorts itself.  Thanks anyway.