Article
Article
Atomic clock
Article By:
Itano, Wayne M. U.S. Department of Commerce, Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado.
Last reviewed:July 2021
DOI:https://doi.org/10.1036/1097-8542.060100
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- Atomic clock, published October 2019:Download PDF
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A device that uses an internal resonance frequency of atoms (or molecules) to measure the passage of time. Atomic clocks (Fig. 1) are relied on internationally as the most accurate time and frequency standards with myriad uses in commerce, industry, and science. The terms "atomic clock" and "atomic frequency standard" are often used interchangeably. A frequency standard generates pulses at regular intervals. A frequency standard can be made into a clock by the addition of an electronic counter, which records the number of pulses. See also: Atom; Digital counter; Frequency counter; Molecule
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