New Real-Time Clock Combines Ensemble of Input Clocks and Provides a More Stable Output than Any of the Input Clocks

Wolfgang Klische, Werner Lange

Abstract:	The Real Time Clock combines ensembles of several input clocks to provide a timescale, which is more stable and robust than any of the individual input clocks, by phase locking a high-stability oscillator to the phase average of the contributing clocks. To particularly profit from the combination of different types of clocks with different stability features the averaging algorithm allows for individual weights for three different time domains to be assigned to each clock. The computed ensemble average may optionally be slowly steered to follow a 1PPS input, typically from a GNSS receiver. Furthermore, the 10MHz and 1PPS outputs may be coherently timeand/or frequency-shifted relative to the computed time scale by user command. The Real Time Clock senses the failure of any contributing clock and automatically removes it from the ensemble without compromising the stability of the output time scale. Likewise, manual removal from, or addition to, the ensemble is possible without disturbing the time scale. Support for this development in an MNPQ project with PTB is gratefully acknowledged.
Published in:	Proceedings of the 47th Annual Precise Time and Time Interval Systems and Applications Meeting January 25 - 28, 2016 Hyatt Regency Monterey Monterey, California
Pages:	206 - 211
Cite this article:	Klische, Wolfgang, Lange, Werner, "New Real-Time Clock Combines Ensemble of Input Clocks and Provides a More Stable Output than Any of the Input Clocks," Proceedings of the 47th Annual Precise Time and Time Interval Systems and Applications Meeting, Monterey, California, January 2016, pp. 206-211. https://doi.org/10.33012/2016.13171
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