[time-nuts] Oscillators and Ovens

Hal Murray hmurray at megapathdsl.net
Wed Nov 1 16:38:55 EDT 2017


> In general, OCXOs have crystals with high Q -> low phase noise,  especially
> compared to a TCXO, which *can't* have high Q, or the  temperature
> compensation circuit can't do it's work. 

I don't understand that.  Why can't I build a high Q TCXO?  I don't need to 
change the compensation very fast.  Are good crystals high enough Q that it 
would take too long?

What's the time constant?  I'd guess it's Q/freq, maybe with factors of 2pi 
or e or ???

That seems small relative to how fast temperature changes.  (but maybe fast 
relative to FCC smearing or things like that)


-- 
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