Seminar Series - 2001-2002

Quartz Crystals vs. Their Environment: Time Bases or Sensors?
(Keeping the World on Time and Your Tanks Full of Gas)

Dr. Errol P. Eernisse
Quartzdyne, Inc.
1020 Atherton Dr., Building C, Salt Lake City, UT  84123
801-266-6958, 801-266-7985 (Fax), errol@quartzdyne.com

Sponsored by the Department of Engineering Mechanics

Date: Thursday, January 31, 2002
Time: 2:30 p.m.
Place:  W183 Nebraska Hall


Keeping accurate time in the presence of acceleration and temperature changes has been a problem for centuries.  This talk starts with a review of the longitude problem for sailors in the 18th century and the novel solution provided by John Harrison.  Some of the inventions he developed to provide a stable frequency source in a harsh environment have parallels in modern quartz crystal oscillators.

Modern telecommunications applications require performance standards for quartz crystals that are far above those of 18th century clocks.  Performance has improved over recent years through extensive research on how to reduce quartz crystal reactions to environmental influences such as acceleration, force, and temperature transients, as well as to a host of manufacturing process variations.  Some recent accomplishments and remaining challenges in the frequency control field will be presented.

During research on environmental influences, it became clear that instead of minimizing the influence of certain environmental effects, it was possible to maximize the influence.  The field of quartz crystal sensors emerged.  Examples that will be presented include high precision temperature and pressure transducers. These sensor applications are used in a variety of situations ranging from benign laboratory environments to the hostile environments at the bottom of an oil well.

The talk will conclude with a brief description of reliable oscillator circuitry used at temperatures as high as 225° C.


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