[billmax]

It’s a Panasonic CF-54 with 2.4GHz i5 CPU. I’ve used this combo for a couple of years without issue, although I’ve never tried phase noise measurements with it until last week. I rarely see uncal USB.

Given your explanation, I think the uncal USB in that capture was likely due to me not using the 2nd (power) USB plug. I was out of ports in that test configuration and had to give up something. It didn’t dawn on me that could be the source of the problem.

Possibly with the dialog box open it is polling the instrument less often, so single port supply is sufficient?

edit:
I had repeated the sequence multiple times. The behavior was consistent in all aspects – uncal USB with higher noise, then no uncal errors and lower noise when dialog box was opened.

Thanks.

• This reply was modified 3 years, 12 months ago by billmax.

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