pxi-5105 THD measurement

[Bob_French]

Can the NI PXI-5105 digitizer be used to perform a THD measurement on ~ 1KHz signal using the LabViews Sound and Vibration toolkit?  Is the Sound and Vibration toolkit required or is it just a nice to have feature that makes life easier?

Thanks

[Aaron O]

Hi Bob,

Have you seen this example? http://zone.ni.com/devzone/cda/epd/p/id/6181

It uses NI-Scope and the Sound and Vibration Toolkit to perform a THD measurement. This sounds like what you are looking for. The Sound and Vibration Toolkit has the required VIs that perform the measurement.

Regards,

Aaron

[Bob_French]

Hi Aaron, yes, I saw that article.  I got together with my LabView developer and we simulated a 1 KHz square wave and sent it through a simulated 1 pole 2 KHz low-pass butterwoth and a simulated 3 pole 2 KHz low-pass butterworth.  We used the analysis tools included with our developer suite edition and in both cases we got a very good THD measurement, 5% for the 3 pole filter and 19% for the single pole filter.  I can't remember what LabView tool we used, I can get it from the delevoper if anyone is interested.

Thanks

Bob French