NIST staff use this equipment to compare time signals transported over fiber-optic cable, a new way to distribute highly accurate NIST time standards. When the large spool of test fiber (330 meters) is inserted into the link between two points, there are negligible changes in delay and stability, indicating that time signals remain virtually unaffected by distance. Signals travel in both directions through the single strand of fiber so that round-trip and one-way delays can be compared. (Commercial brand names were deleted from the photo.)
Credit: J. Sherman/NIST
The nation should bolster research and development of systems that distribute accurate time via fiber-optic cable and radio as part of the effort to back up GPS and enhance the resilience of critical infrastructure that depends on it, according to a new report by the National Institute of Standards and Technology (NIST).
Many aspects of the U.S. economy and quality of life depend on accurate time, as detailed in a second, companion report. Time is a crucial underpinning of telecommunications networks, for example, as well as the power grid and stock markets, among other users.
The work was funded in part by the U.S. Department of Homeland Security, which commissioned NIST to “study and asses ..
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