The NATO III 5 Mhz Distribution System

A. Vulcan, M. Bloch

Abstract:	This paper describes a high performance 5 MHz distribution system having extremely low phase noise and jitter characteristics and providing multiple buffered outputs. The system is completely redundant with automatic switchover and is self-testing. Faults can be isolated to a modular level by observing front panel status indicators. Since the 5 MHz reference signals distributed by the NATO III distribution system are used for up-conversion and multiplicative functions, a high degree of phase stability and isolation between outputs is necessary. Unique circuit design and packaging concepts are utilized to insure that the isolation between outputs is sufficient to guarantee a phase perturbation of less than 0.0016" when other outputs are open circuited, short circuited or terminated in 50 ohms. The circuit design techniques include high isolation cascode amplifiers, the use of negative feedback to stabilize system gain and minimize circuit phase noise contributions, the use of balanced lines in lieu of single ended coaxial transmission media to minimize pickup and degradation of noise floor and the development of simplified fault detection and switchover circuitry to insure continuous operation. The distribution system is fed by redundant high stability quartz frequency standards which use special crystals with low phase noise and jitter and daily aging rate better than 5 X 10-11.
Published in:	Proceedings of the 12th Annual Precise Time and Time Interval Systems and Applications Meeting December 2 - 4, 1980 Goddard Space Flight Center Greenbelt, Maryland
Pages:	743 - 764
Cite this article:	Vulcan, A., Bloch, M., "The NATO III 5 Mhz Distribution System," Proceedings of the 12th Annual Precise Time and Time Interval Systems and Applications Meeting, Greenbelt, Maryland, December 1980, pp. 743-764.
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