I believe - if I understand correctly - that Magnus refers to realizations based on what has been referred to as "the Schodowski patent"
Dual mode quartz thermometric sensing device <https://scholar.google.com/citations?view_op=view_citation&hl=en&user=tVnR8zIAAAAJ&citation_for_view=tVnR8zIAAAAJ:u-x6o8ySG0sC> SS Schodowski US Patent 4,872,765 as referenced here: Resonator self-temperature-sensing using a dual-harmonic-mode crystal oscillator <https://scholar.google.com/citations?view_op=view_citation&hl=en&user=tVnR8zIAAAAJ&citation_for_view=tVnR8zIAAAAJ:u5HHmVD_uO8C> SS Schodowski Frequency Control, 1989., Proceedings of the 43rd Annual Symposium on, 2-7 Not easy to do, but truly a measure of resonator temperature variations. On Sat, Mar 12, 2016 at 7:33 AM, Magnus Danielson < [email protected]> wrote: > Hi, > > For the 10811 you can modify it to change mode and then use that mode to > measure and trim the temperature oven. > > There exists crystal oscillators where the 10 MHz is a traditional SC-cut > mode and then a 30 MHz mode is exercised which measures the crystal > temperature. In the Microprocessor Controlled Crystal Oscillator (MCXO) one > then measure the difference in frequency and uses this to re-synthesize a > correction on the 10 MHz. The benefit is that it is the temperature of the > oscillating crystal that is being measured. > Naturally, it could be used for oven control and/or EFC control too. > > The MCXOs exists in manufacturing, but whenever you ask about them they > just wonder what military project are you working on. > > I'd love to experiment with this form of temperature sensing one day, when > I have time... if that ever happens... > > Cheers, > Magnus > > > On 03/12/2016 10:21 AM, ken hartman wrote: > >> Interestingly, the use of AC-cut crystals (high linear tempco of >> frequency) >> is found in the development of OCXOs. Using a reference AC-cut resonator - >> in place of the final AT/SC resonator - one can learn much about the >> thermal characteristics of the oven loop performance. While not a precise >> temp sensor, it is a high sensitivity indicator of temperature >> variations >> of the resonator. >> >> On Fri, Mar 11, 2016 at 11:44 PM, Bill Hawkins <[email protected]> >> wrote: >> >> It may be that the need for that kind of resolution died out. >>> >>> The next step up from quartz thermometry is resistance thermometry. >>> The linearization equation for platinum has enough terms to make it >>> uncertain around .01 C. >>> Temperature calibration baths usually use platinum resistance sensors. >>> >>> It may be that the triple point of water does not have the certainty to >>> reach '0.0001C' >>> >>> Disclaimer: I only worked with industrial sensors from Rosemount, Inc. >>> as an employee. >>> >>> Bill Hawkins >>> >>> >>> -----Original Message----- >>> From: Alan Ambrose >>> Sent: Friday, March 11, 2016 11:42 AM >>> >>> Hi, >>> >>> I hope this is still relevant and not too off-topic...but since it >>> involves crystals and tempco... >>> >>> Quartz thermometers (e.g. the HP 2804A) with their 'linear cut' crystals >>> and '0.0001C resolution' seem to have been a thing from the mid-60's to >>> the mid-80's: >>> >>> http://www.hparchive.com/Journals/HPJ-1965-03.pdf >>> >>> There still appear to be some manufacturers making the crystals: >>> >>> http://www.statek.com/products/pdf/Temp%20Sensor%2010162%20Rev%20B.pdf >>> >>> Anyone know why they died out? Did a better technology replace them? >>> >>> TIA, Alan >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
