[time-nuts] Timepod Phase Noise Measurements and 3 corner hat

[James Flynn]

Martyn Smith <martyn at ...> writes:


> MEASUREMENT TECHNIQUE
> 
> We have three sources close in frequency (within 1 x 10E-8 of each 
other).
> 
> Two sources are connected to the Ch0 and Ch 2 inputs of the timepod, the 
> unit under test to the ref input.
> 
> According to John, the result will be the actual phase noise of the ref 
> input, even if it is lower than the two other sources.
> 
> No further calculations need to be made.
> 

The is a publication by the NPL that talks about a similar technique, but 
comes to a somewhat different conclusion.

http://publications.npl.co.uk/npl_web/pdf/mgpg68.pdf

Bottom line: it holds that the phase noise of all three sources can be 
determined if they are taken two at a time; one as ref and the other as 
the DUT.