RFSA THD

[nvjhv]

Hello!

please could anyone answer to my question?

How to measure RF signal THD in RFSA?

I have found only scope examples

thanks in advance

A

[dansch]

Hello nvjhv,

I understand you are looking to perform a THD analysis with RFSA. I believe the scope example you are referring to is located here and utilizes the Sound and Vibration Toolkit. The exact same program is installed in LabVIEW with the Sound and Vibration Toolkit but uses the NI-DAQmx driver instead of NI-SCOPE. This example is installed in your LabVIEW directory at \<labview>\examples\Sound and Vibration\Audio Measurements\SVXMPL_One Shot THD (DAQmx - no excitation).vi.

Unfortunately, the same example has not yet been created with the RFSA driver, though by examining the SCOPE and DAQmx versions, you may be able to implement the same functionality pretty easily. The particular Sound and Vibration Toolkit function of interest may be reviewed further at the following page: http://zone.ni.com/reference/en-XX/help/372416A-01/sndvibtk/thd_harmonic_components/. Hope this helps,

[nvjhv]

Thank you.

As I understand I can perform THD for baseband signal, or modulated signal, I mean not for carrier signal

For example, i just generate single tone in 100MHz, and THD fundamental frequency shows something strange and not normal, but when I generate for example AM signal, it shows the spectral komponent of AM (which has message frequency shift from carrier) as a fundamental, and calculate THD of this component, am I right?

And also there is no example for IQ signal, but i think Power Spectrum is also enough