waveform calcul frequency

[Sebin]

Hi,

I want calculate the frequency of a waveform captured.

But I have Labview base, so I haven't VI signal process.

How calculate the frequency of my waveform ?

Do you have a VI for that ?

Thank in advance.

Seb

[Ben_L]

Hi Seb,

Unfortunately LabVIEW base does not contain the functionality to calculate the frequency, the following knowledge based article details the limitations of LabVIEW base.

http://ae.natinst.com/operations/ae/public.nsf/web/searchinternal/08ea09e507da8246862571ed005c99eb?OpenDocument 

Kind Regards

[Henrik_Volkers]

Seb,

depending on the resolution needed, here is an idea that might work (not tested):

-calc the mean of your signal and subtract the offset (if there is some)

now basically determine the zero crossing, measure the time intervals between positive(negative) slopes and you can calculate the frequency

take more periods to increase resolution

bandpass your signal in the region of interest, analog or digital (a 'slow' basic digital filter can be written in a for loop with shift registers) 

Message Edited by Henrik Volkers on 10-07-2008 03:34 PM