[time-nuts] Frequency referenced temperature regulator

[Brooke Clarke]

Hi John:

Is there a source of crystals cut for temperature measurements?

Have Fun,

Brooke Clarke
http://www.PRC68.com


John Ackermann N8UR wrote:
> Sounds like the way the HP 2804 quartz thermometer works.  HP came up with a special crystal cut that was very linear with temp, and I suspect the hardest part of your idea might be the linearity of the tempco of your crystal.  But you could characterize that and store in a correction table.
>
> John
>
> On Nov 8, 2010, at 10:04 AM, "Poul-Henning Kamp"<phk at phk.freebsd.dk>  wrote:
>
>    
>> I'm contemplating building a small temperature control enclosure for
>> testing various electronics.
>>
>> I have a handful of peltiers suitable for the purpose, and was
>> pondering the right control mechanism.
>>
>> Most people would reach for a NTC, put it in a wien-brige etc etc.
>>
>> But since I happen to have access to much more stable frequencies
>> than voltages, I thought of a different way:
>>
>> 1. Mount a X-tal-osc with really lousy tempco inside the enclosure.
>>
>> 2. Compare its output to a stable reference frequency.
>>
>> 3. Use the output of the phase comparator to drive the Peltier.
>>
>> It is basically a PLL where temperature is used as EFC...
>>
>> Has anybody tried that ?
>>
>> -- 
>> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
>> phk at FreeBSD.ORG         | TCP/IP since RFC 956
>> FreeBSD committer       | BSD since 4.3-tahoe
>> Never attribute to malice what can adequately be explained by incompetence.
>>
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