Hello,
in the attachment you can see the noise floor of my 8591A. My question: is it normal, that the noise floor increases at higher frequencies?
I know from other analyzers (Advantest), that the noise floor is constant over the whole frequency range.
Is there a new calibration necessary or how can i get constant noise floor?
Thank you!
Kind regards,
Thorsten
in the attachment you can see the noise floor of my 8591A. My question: is it normal, that the noise floor increases at higher frequencies?
I know from other analyzers (Advantest), that the noise floor is constant over the whole frequency range.
Is there a new calibration necessary or how can i get constant noise floor?
Thank you!
Kind regards,
Thorsten
What you are seeing on the 8591A screen is completely normal. The rise in the noise floor of the instrument is due to the frequency corrections being applied. If you didn't see this I would say that something was wrong with the instrument... You can verify this by turning the corrections off by pressing CAL -> MORE -> CORRECTION OFF
You are seeing the rise in the noise floor as the frequency gets higher due to the fact that the loss of the front-end components of the instrument go up with frequency, requiring more corrections, and of course corrections often come with a cost to sensitivity. However, in narrower spans this is not as noticable since the corrections are applied differently, not as much post detection video shifting is done. It can use additional amplifier gain with smaller spans to compensate for the frequency response of the front-end.
I can't speak for the Advantest instrument that you have, as I don't know how they apply frequency response corrections, or if the particular instrument that you have does this at all...