Frequency measurement

[cosmin_ro]

I have a waveform measured with DMM 4070. Is there a function in Advanced Analysis Library which calculates the frequency and other caracteristics of the signal ? An example would be very helpfull.

  Thank you

[Dennis_Knutson]

Sure. Signal Processing>Waveform Measurements has the Extract Single Tone and the Timing and Transition Express VI.

You don't mention what other characteristcis you want to get but if you were to turn on the Context Help, you would get a pop-up window and as you moved your mouse over the functions on a palette, see an image of the VI's icon and a brief description. Expetned help is then just a click away.

[cosmin_ro]

Thank you Dennis.

There is no such path in CVI:  Signal Processing>Waveform Measurements.

I am using CVI 8.5 full development kit and DMM 4070.

[Dennis_Knutson]

Sorry. When you mentioned Advanced Analysis I thought you were talking about the Advanced Analysis palette in LabVIEW. I don't have CVI installed right now so I don't know where the function is but I'm pretty certain there is something equivalent in CVI. You might have to search around a bit. You might also want to post to the LabWindows/CVI board.

[J_Thomas]

Hi  cosmin_ro,

As far as I can tell, there is no built in function in CVI to extract the main tone out of a signal (like the Extract Single Tone VI and the Tone Measurements Express VI found in LabVIEW).

One suggestion would be to take the power spectrum of the signal using the AutoPowerSpectrum function, and then use the PeakDetector function to obtain the main frequency components.

You could polish the result by filtering the data to work only on a specific frequency band that you are interested in, remove the DC component, or perform some averaging to get a more accurate measurement.