Title :
The influence of pressure and humidity on the medium and long-term frequency stability of quartz oscillators
Author_Institution :
NBS, Boulder, CO, USA
Abstract :
It is shown that the medium-term frequency stability of four different 5-MHz oscillators controlled by two different types of AT-cut resonators is sensitive to changes in atmospheric moisture and possibly pressure. Stabilizing the pressure and humidity, in addition to the normal parameters in an otherwise controlled laboratory setting, improves the frequency stability for measurement times in the region of hours to days. The mechanism by which fluctuations in moisture and possibly pressure bring about frequency changes is speculated upon, noting that the effect could be due to changes in the thermal gradients, changes in the dielectric constants, or residual leakage between critical circuit elements. A simple test is introduced to determine the relative importance of thermal gradients within air-enclosed ovens
Keywords :
crystal resonators; frequency stability; 5 MHz; AT-cut resonators; air-enclosed ovens; atmospheric moisture; atmospheric pressure; critical circuit elements; crystal resonator; dielectric constants; long-term frequency stability; medium-term frequency stability; quartz oscillators; residual leakage; thermal gradients; Atmospheric measurements; Dielectric measurements; Frequency measurement; Humidity control; Humidity measurement; Laboratories; Moisture control; Oscillators; Pressure control; Stability;
Conference_Titel :
Frequency Control Symposium, 1988., Proceedings of the 42nd Annual
Conference_Location :
Baltimore, MD
DOI :
10.1109/FREQ.1988.27615
