[time-nuts] Noise Floor

[Anders Wallin]

Thanks for posting these!
The user-manual provides some details on the internals:
http://www.miles.io/PhaseStation_53100A_user_manual.pdf
Figure 6, page 35, would indicate that there is no analog mixing stage,
just direct ADC.
Maybe it also shows the ADCs clocked at (max) 125 MHz, with some HPF and
under-sampling going on in order to measure a 200 MHz carrier!?

It would be interesting to know what ADC was used and if there's an
SDR-board out there that uses the same ADC.
Our experience with the Ettus radios is that although they have 2 channels
there is a lot of cross-talk between rx1 and rx2 channels, which makes a
diy SDR-based phase-meter challenging.

Another paper to look at is the R&S one
https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/dl_application/pdfs/FSWP_Paper_EFTF2016_V02.pdf

I can try to dig out my old comparison-data [1] and include this new data,
if Bob makes the results (or raw data) available as numbers somewhere.

Anders
[1]
http://www.anderswallin.net/2015/12/spectrum-analyzer-or-phase-noise-probe-for-phase-noise-measurement/