TRIPLY-REDUNDANT PRECISION TIME AND FREQUENCY STANDARD

D. Silvermetz, M. Bloch, M. Meirs

Abstract:	This paper describes a triply-redundant precision time frequency standard. The standard combines three high performance, field-proven Frequency Electronics devices; namely, the cesium beam frequency standard, the rubidium frequency standard and the so-cut quartz oscillator in a single 5-1/4" high rack-mounted instrument. Switching between redundant subsystems is accomplished automatically in a glitch-free manner (i.e., negligible phase perturbation), utilizing a process of dynamic phase-matching in conjunction with digital memory circuits. The system design is based upon the incorporation of a Model FE-560 OA Rubidium Standard within the Model FE-5440A (military nomenclature 0-1824/0) Cesium Frequency standard, and utilization of disciplining phase lock loop circuitry from the AN/U RQ-23A Disciplined Time Frequency standard. In the primary mode, the system functions as a Cesium Standard with a long-term stability of <1 x 10-11. In the secondary (back-up) mode, the rubidium standard provides a thirty day stability of <3 x 10-11. The tertiary (backup) mode offers the low drift rate of the sc-cut quartz oscillator, namely <1 x 10-11 per day.
Published in:	Proceedings of the 19th Annual Precise Time and Time Interval Systems and Applications Meeting December 1 - 3, 1989 Sheraton Hotel Redondo Beach, California
Pages:	113 - 132
Cite this article:	Silvermetz, D., Bloch, M., Meirs, M., "TRIPLY-REDUNDANT PRECISION TIME AND FREQUENCY STANDARD," Proceedings of the 19th Annual Precise Time and Time Interval Systems and Applications Meeting, Redondo Beach, California, December 1987, pp. 113-132.
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