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N4373C : Understanding specifications and procedure to measure uncertainty

Question asked by m_rius on Jan 24, 2014
Latest reply on Mar 10, 2014 by mkelly
Dear Sir,

We have a LCA N4373C with a VNA N5245A in our lab.

I have been reading a lot about measurement uncertainty, errors... As far as i know, the procedure to obtain the specifications of a instrument and the way to show the results is complex. Specifically, to calculate a uncertainty there are some references from international entities (like JCGM 1000:2008 GUM 1995: Guide to the expression of uncertainty measurement).  

I would like to someone clarify the specifications that are detailed in the datasheet (attached) of my instrument. For example, in page 18, specifications for O/O measurements @ 1550 nm are presented:

- Which is the difference between "relative" and "absolute" frequency response uncertainty? In page 9 there are definitions of both but they don't help me to understand the difference.

- Regarding the Phase uncertainty, this uncertainty is relative or absolute? 

- Which is the procedure to measure or calculate these three uncertainties and also the frequency response repeatability in order to check these specifications? The measurement conditions are detailed but no the procedure of the measurent or the measurements.

- This uncertainties have been calculated following the GUM 1995? In this case, it is a type A (evaluated by statistical methods) or type B (by approximations).  Which coverage factor do you assume? "2" in order to have a confidence of 95%? In this sense, I would like to reproduce the measurements and make the corresponding calculation of the uncertainty in order to obtain the value that is given in the specifications.

Thanks for your responses