[time-nuts] quartz thermometers

[Daniel Mendes]

Quartzdyne makes pressure and temperature sensors for the oil industry
based on quartz xtals:

http://www.quartzdyne.com/quartz.html

Daniel
Em 13/03/2016 01:04, "jimlux" <jimlux at earthlink.net> escreveu:

> 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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