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GLOSSARY OF COMMON TERMS
NIST*
The National Institute of Standards and Technology maintains the primary frequency standard for
the United States. The NIST also coordinates the United States time and frequency standards with
other world standards. The NIST provides time and frequency services for United States clientele.
WWVB*
The WWVB is an AM radio station in Ft. Collins, Colorado, managed by the NIST. The WWVB’s
function is to broadcast time-of-day information derived from the NIST atomic clock, located in
Boulder, Colorado.
ATOMIC CLOCK*
An atomic clock is an extremely accurate time device measuring time by the movements of electrons
in cesium atoms.
The NIST atomic clock is one of the most precise clocks in the world, accurate to
10 billionths of one second. The NIST’s atomic clock contributes to the international group of clocks
calculating the Coordinated Universal Time (UTC)—the official world time.
RADIO-CONTROLLED TIME*
A radio-controlled time device is often confused with an atomic clock. However, a radio-controlled
time device receives its time information
from
the atomic clock each day through an internal
antenna. The radio-controlled time device searches for an exact time signal every night when the
signal from the WWVB is the strongest. The signal can be received up to 2,000 miles away through
a radio-controlled time device.
LCD
“LCD” is an acronym for ”Liquid Crystal Display”. This is a common type of display screen used in
televisions, computers, watches, and digital clocks.
CELSIUS (°C)
Celsius is metric system’s unit of measurement used to calculate temperature.
FAHRENHEIT (°F)
Fahrenheit is the common unit of measurement used to calculate temperature in the United States.
*For more information regarding the NIST, WWVB, atomic clock, and radio controlled time, please
visit the NIST official website: http://www.boulder.nist.gov/timefreq/stations/wwvb.htm
