Precision Time and Frequency Source and Systems Research and Development at The Johns Hopkins University Applied Physics Laboratory

A.G. Bates, M.T. Boies, M.C. Chiu, R. Kunski, J.J. Suter

Abstract:	The Applied Physics Laboratory (APL) has a Time and Frequency Laboratory equipped with several hydrogen masers, cesium beam standards, and two Global Positioning Satellite receivers that are tied into the Bureau of the International Hour network of time standards. This laboratory gives APL the capability to perform much of our advanced research in time and frequency standards and provides reference signals with excellent short- and long-term stabilities. APL developed the NR Hydrogen Maser for NASA's Crustal Dynamics Project in the late 1970s and early 1980s. Since then, APL has continued research and development in advanced hydrogen maser technology under NASA's Research and Technology, Objectives and Plans Program. Two major areas of research activity are the source and state selector assembly for increased efficiency and the cavity design for a better temperature coefficient. Initial results of these activities will be presented in this paper. In addition to hydrogen maser research, APL has expanded research activities to supercooled quartz crystal oscillators and the Integration of solid-state laser systems into quantum frequency standards. With respect to the laser systems, we will discuss our activities in optically pumped cesium standards and Fabry-Perot interferometers. APL has been active in the research and development of space-flight qualified oscillators and time and frequency standards for satellite applications for the last 25 years. In recent years, our activities have included developing SC cut resonators and designing oscillators with both excellent phase noise and long-term drift. Our developments have expanded from just oscillators to complete satellite clock systems, including power conditioning, command /telemetry, and frequency multiplication and distribution amplifiers; a summary of these developments will be given. Significant research efforts are also under way on the radiation susceptibility of quartz crystals; that topic will also be discussed in this paper.
Published in:	Proceedings of the 18th Annual Precise Time and Time Interval Systems and Applications Meeting December 2 - 4, 1986 DuPont Plaza Hotel Washington, DC
Pages:	55 - 70
Cite this article:	Bates, A.G., Boies, M.T., Chiu, M.C., Kunski, R., Suter, J.J., "Precision Time and Frequency Source and Systems Research and Development at The Johns Hopkins University Applied Physics Laboratory," Proceedings of the 18th Annual Precise Time and Time Interval Systems and Applications Meeting, Washington, DC, December 1986, pp. 55-70.
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