[time-nuts] Frequency referenced temperature regulator
John Ackermann N8UR
jra at febo.com
Mon Nov 8 16:26:02 UTC 2010
I've never looked. The original HP Journal article talked about the characteristics of the crystal. I think it's called an L cut. The frequency used was around 26 MHz because that yielded an easy Hz/degree ratio.
On Nov 8, 2010, at 10:21 AM, Brooke Clarke <brooke at pacific.net> wrote:
> 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.
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>>
>>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
More information about the time-nuts
mailing list