[time-nuts] ensemble oscillators for better stability

John Ackermann N8UR jra at febo.com
Fri Dec 28 20:19:43 UTC 2012


Hi Corby -- I've often thought of the idea of mixing two 5 MHz sources in a DBM and using the resulting 10 MHz, so I'm really curious to see how this works out.  Seems like injection locking  is the most likely problem you'd have to deal with.

Let us know how this goes!

John

On Dec 28, 2012, at 2:12 PM, cdelect at juno.com wrote:

> Hi,
> 
> I've been playing around with 2 HP 5065A standards to see if averaging
> them will give better stability.
> 
> The results so far are:
> 
>                     1 sec        10 sec    100 sec
> unitA            1.28-12    3.83-13   1.33-13      
> unitB            9.31-13    3.44-13   1.18-13
> combined     8.95-13    3.09-13   8.95-14
> 
> Each unit was adjusted for equal amplitude into a resistive power
> combiner and also adjusted so their phase was coincident prior to
> starting the plots.
> The main problem was getting their relative frequencies close enough so
> that there was no drift during the measurements.
> Not a trivial accomplishment for the 100 sec tau!
> 
> I'm thinking now of a way to loosely lock the phase of one unit to the
> other to simplify the setup.
> 
> One different idea I had that I'd like some feedback on:
> 
> If I take both units into a double balanced mixer, then take the
> resulting 10MHz and divide it back to 5MHz would I get the same
> improvement? 
> 
> This method would be much simpler!
> 
> Happy New Year!
> 
> Corby Dawson
> 
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