Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Measuring Time and Comparing Clocks

Published

Author(s)

Judah Levine

Abstract

I will discuss methods of comparing and synchronizing clocks and the procedure of characterizing their performance in terms of the two-sample Allan variance. I will describe methods that are used when the device under test and the reference device are in the same facility and when they are at different locations linked by a communications channel. The reference device can be a national time scale, and I will briefly describe how national time scales are defined. In each case I will use the Allan variance as a tool to understand the characteristics and limitations of the various methods. I will also introduce the concepts of traceability and of a cost-benefit analysis into the synchronization procedure.
Citation
Handbook of Measurement in Science and Engineering
Volume
Ch. 59
Publisher Info
John Wiley, Hoboken, NJ

Keywords

Allan Variance, Common-View, GPS Satellites, Network Time Protocol, Time and Frequency Distribution

Citation

Levine, J. (2016), Measuring Time and Comparing Clocks, John Wiley, Hoboken, NJ, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=915305 (Accessed April 23, 2024)
Created April 1, 2016, Updated February 19, 2017