David W. Allan

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2026-06-23

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Who is this?

David Wayne Allan (born September 25, 1936) is an American atomic clock physicist and author of the Allan variance (AVAR), also known as the two-sample variance, a measure of frequency stability in clocks, oscillators and other applications. He worked for the National Bureau of Standards in Colorado. In 1981 Allan developed the Modified Allan variance (MVAR) and then developed the Time variance (TVAR) in the late 1980s. AVAR, MVAR, and TVAR were made IEEE standards in 1988, and are used widely i