[time-nuts] quartz thermometers

jimlux jimlux at earthlink.net
Sat Mar 12 21:10:54 EST 2016


On 3/12/16 7:35 AM, Bob Camp wrote:
> Hi
>
> The conventional MCXO uses an AT cut crystal rather than an SC. It
> runs on the fundamental and the third overtone. You can build one
> with just about any normal fundamental crystal. There are also people
> doing OCXO’s sort of the same way. Back when the MCXO came out, it
> was about the only way to get a TCXO that had < 1x10^-8 sort of
> stability. Now you can get that with a cheap (as in not $5,000 each)
> commercial IC based TCXO.
>
>
And heck, if you can tolerate the 1.5W warm up power, you can get ppb
sorts of accuracy in a OCXO at 250mW. (Vectron EX421)  They're a few 
hundred dollars.

The Qtech MCXO is about 100 mW, and somewhat bigger than the EX421 (not
much bigger)

The vectron MX-503 is in the 50 ppb range at 40 mW (I don't know how it 
does the internal compensation.. maybe it uses some other kind of 
temperature sensor)



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