[time-nuts] Phase noise measurements - getting started.

David Kirkby david.kirkby at onetel.net
Sun Apr 24 09:52:31 EDT 2005

How is the best way to make phase noise measurements, starting from 
limited test kit?

Methods I've seen rely on a low noise oscillator - not a lot of use if 
you don't know the noise performance of any of your oscillators. Another 
assumes your two oscillators each contribute the same amount of noise, 
which is probably not true on old oscillators, even if they are the same 

A third seems a bit more promising - the use of 3 oscillators and 
solving a set of simultaneous equations. I've not looked at the maths of 
this, but assume that it will not work too well if two oscillators are 
quite good, and a third bad.

I should soon have a 5370B time interval counter with its own 
oscillator, plus an oscillator I want to test. I also have access to a 8 
or so year old spectrum analyser (never recalibrated), scopes, mixers, 
lock-in amplifiers and general lab kit.

My pocket money does not quite stretch to the latest all singing all 
dancing kit from Agilent.

Dr. David Kirkby,

Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/

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