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N9030A Integrated phase noise discrepacies VXA Module vs Phase Noise Module

Question asked by attomitch on Apr 20, 2015
Latest reply on May 21, 2015 by attomitch
Dear experts,

I am trying hard to solve a very important issue concerning my delicate phase noise measurements on a very low noise and tightly phase locked RF signal. 
I typically use the direct measurement tool having the Phase Noise module in the PXA N9030A, displaying as a Log plot the Power Spetral Density. The marker function allows me to integrate the phase noise over the band the user assign, which is great, but for data evaluation I would love to obtain the same value when plotting the raw data on my computer. Apperantly the instrument changes automatically the RBW decade by decade, and I can't find a way to find that value for computing and plotting the cumulative contribution of phase noise over the Fourier frequencies offsets from carrier. 
Is there a way to get those info? How is in details the computation done on the Phase Noise module?

I then purchased also the VXA Module, which is just amazing for demodulating analog signals, but when plotting the PSD of my locked signal, the Phase Noise level seems different, even accounting tha fact that it is displayed as Double Side Band and not L(f) as the other module. In addition, I can't understand another thing: defyning the RBW as the minimum possible for 5 MHz span (98.xxx Hz), it will differ from the frequency delta of the frequency axis (24.xxx Hz) which I need to create as an array on my computer to plot the graph (the exporting CSV data do not provide the frequency axis as in old fashion VSA). 

My goal is to be able to retrieve reliable raw data and compute properly the integration. I would love to have some help on this purpose.
I am extremely grateful and I am looking forward for a reply!

My best,

Mitch  

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