cwt scale vs. frequency

[steve_84]

Hi!

I'm using the CWT of the Advanced Signal Processing Toolkit to analyse a signal from accelerometers.

Using the SYM8 wavelet over about 2000 scales gives me the resulting scalogram. FFT of the mother wavelet shows me that the center frequency(fc) of this wavelet is 0,75.

My region of interest is between 0 and 500Hz.. 

When I calculate the corresponding pseudo frequencies(fp) with this center frequency and the half sampling rate(fs) of 25600 I get: 

0-500Hz results in Scale from Max to 25!

Compared wih the spectogram I know that my information is in the region between Scale 1100 and Max.Scale....

Can somebody tell my where my mistake is hiding?

I calculated: fp = fc/a *fs/2

Thank you... Steve 

[ralfn]

Hi Steve,

I'm very sorry for the delay.

I need a little bit more information to help you better.

It would be great if you can send me a small VI with your input-data so I can take a look at it. 

Which version of LabVIEW and the Toolkit do you use?

Thank you and a nice weekend.

Ralf N.

Application Engineering 

Message Edited by ralfn on 11-07-2008 09:15 AM

[steve_84]

Hi!

Thank you for your reply.

I'm using Labview 8.5 at my University (TU Graz). I think it's the SPT 7.0 but I'm not shure.

Attached my input signal as a txt file. I used the data as waveform file.

Additional I added the STFT picture and the CWT Scalogram. As you can see the frequency range 0-500Hz is somewhere between Scale 1100

and ScaleMax. 

lg Steve 

[steve_84]

I use the WA Contineous Wavelet Transform.vi 

I looked it up an I have the Advanced Signal Processing Toolkit 7.5.0

lg Steve