I’m having some difficulty using the QA480 with the QA402. I think it’s the FR measurement and export part. Since the software is slightly different from the 401. Any advise?
Thanks in advance!
Hi @tonywood, which part specifically is giving you trouble? Can you share the export screen that shows the summary of the measurement?
The best I can get is about -116DB THD+N, Thought I should be getting closer to -120. I click freq response and it runs, then I export it. How to I configure it? Or is this correct?
Thank you
Hi @tonywood, from your measurement, your 2H is in the right place, and at -142 dbc we know that isn’t degrading anything. so, that means the noise is the issue. Can you add the measurement N-D dBV. That will show the noise while ignoring the distortion contribution.
We can roughly estimate what that number is. Your are at 19 dBV, and the THD says the noise is -115.88 below that, so your noise (absent harmonics) is likely about -96.9. That suggests whatever is out around 20 kHz isn’t a contributor even if not a harmonic (and likely it isn’t).
But from the N-D figure we can try to figure where to go next.