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An algorithm for synchronizing a clock when the data are received over a network with an unstable delay

Published

Author(s)

Judah Levine

Abstract

I will describe a method for synchronizing a clock to a remote time standard when the channel connecting to two has significant delay variation that can be described only statistically. The method compares the Allan deviation of the channel fluctuations to the free-running stability of the local click, and computes the optimum interval between requests based on one of three selectable requirements: (1) choosing the highest possible accuracy, (2) choosing the best tradeoff cost vs. accuracy, or (3) minimizing the number of request to realize a specific accuracy. Once the interval between requests is chosen, the final step is to steer the local clock based on the received data. I will discuss a typical adjustment algorithm, which supports both the statistical considerations based on the Allan deviation comparison and the timely detection of errors.
Citation
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control
Volume
PP
Issue
99

Keywords

Allan variance, Digital Time transfer, Internet Time Service, NIST Time Servers

Citation

Levine, J. (2015), An algorithm for synchronizing a clock when the data are received over a network with an unstable delay, IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, [online], https://doi.org/10.1109/TUFFC.2015.2495014 (Accessed May 21, 2024)

Issues

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Created October 27, 2015, Updated November 10, 2018