[time-nuts] Very challenging phase noise measurement, does anyone have an idea??

Bill Fuqua wlfuqu00 at uky.edu
Thu Dec 6 14:35:17 UTC 2012

    If you want a low noise mixer use a varicap mixer. A varicap has no 
ohmic characteristics thus
no Johnson noise.
    Secondly, You can create low noise  harmonics using a vaicap multiplier 
or a nonlinear transmission
line using inductors and nonlinear capacitors (varicaps). NIST has been 
doing this for some time and even has
used nonlinear fiber optics to phase lock oscillators to lasers as atomic 
references. Guys got Nobel Prize for that
one. Measuring the phase noise at a high order harmonic has the advantage 
that the phase is multiplied by the harmonic
number thus bring the sidebands up further from the noise floor.
   Here is a reference, that could be scaled down for your frequency, on 
phase noise measurements using harmonics produced
by a nonlinear transmission line. This example just a few sections in its 
nonlinear transmission line
Bill wa4lav

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