[time-nuts] Morion MV89A Repair

John Miles jmiles at pop.net
Sun Feb 26 20:48:26 UTC 2012



> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-
> bounces at febo.com] On Behalf Of Tom Knox
> Sent: Sunday, February 26, 2012 9:41 AM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Morion MV89A Repair
> 
> 
> Is this the paper you are speaking of?
> Google:  Optimization of Drive-Level in High Stability Low-Noise OCXOs
> 
> Thomas Knox

That's not the one Bob (and I) was talking about, but there are some
interesting contradictions between the paper you mentioned:

 
http://www.magicxtal.com/articles/Optimization%20of%20Drive-Level%20in%20Hig
h%20Stability%20Low-Noise%20OCXOs.PDF 

and Rakon's article:

http://www.rakon.com/Products/Public%20Documents/Whitepapers/PHASE%20NOISE%2
0IN%20CRYSTAL%20OSCILLATORS.pdf

The Rakon author states that the flicker and white PM regions, including the
broadband floor, are influenced by factors other than the crystal (Figure
9).   

Meanwhile, the Russian authors of the first paper state repeatedly that the
broadband noise floor is a function of the crystal current, and that
close-in noise isn't affected by crystal current.

It's obvious enough that high levels of crystal current are bad for
long-term stability and aging, but it's not as easy to see why high crystal
current in itself should rule out a good broadband noise floor.  There are a
lot of assertions in the literature, especially in the magicxtal.com paper,
that are backed up by measurements but not by solid analysis. 

-- john




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