Primary time standard

Primary time standard

In telecommunications, a primary time standard is a time standard that does not require calibration against another time standard.

"Note 1:" Examples of primary time, ("i.e.", frequency standards) are caesium standards and hydrogen masers.

"Note 2:" The international second is based on the microwave frequency (9,192,631,770 Hz) associated with the atomic resonance of the hyperfine ground state levels of the caesium-133 atom in a magnetically neutral environment. Realizable caesium frequency standards use a strong electromagnet to deliberately introduce a magnetic field which overwhelms that of the Earth. The presence of this strong magnetic field introduces a slight, but known, increase in the atomic resonance frequency. However, very small variations in the calibration of the electric current in the electromagnet introduce minuscule frequency variations among different caesium oscillators.

Source: from Federal Standard 1037C and from MIL-STD-188


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • primary time standard — pirminis laiko standartas statusas T sritis automatika atitikmenys: angl. primary time standard vok. Primärzeitstandard, m rus. первичный стандарт времени, m pranc. étalon primaire de temps, m …   Automatikos terminų žodynas

  • primary time standard — pirminis laiko etalonas statusas T sritis radioelektronika atitikmenys: angl. primary time standard vok. Primärzeitnormal, n rus. первичный эталон времени, m pranc. étalon primaire de temps, m …   Radioelektronikos terminų žodynas

  • Time standard — A time standard is any officially recognized specification for measuring time: either the rate at which time passes; or points in time; or both. For example, the standard for civil time specifies both time intervals and time of day. A time scale… …   Wikipedia

  • Time in physics — In physics, the treatment of time is a central issue. It has been treated as a question of geometry. One can measure time and treat it as a geometrical dimension, such as length, and perform mathematical operations on it. It is a scalar quantity… …   Wikipedia

  • Standard Oil — Infobox Company company name = Standard Oil company company type = Ohio Corporation (1870 1882), Business Trust (1882 1892), New Jersey Holding Company (1899 1911) [cite web |url=http://www.bgsu.edu/departments/acs/1890s/rockefeller/bio2.htm… …   Wikipedia

  • Primary Atomic Reference Clock in Space — The Primary Atomic Reference Clock in Space or PARCS is an atomic clock mission once scheduled to fly on the International Space Station (ISS) in 2008, but cancelled to make way for the Vision for Space Exploration.[1] The mission, to have been… …   Wikipedia

  • Standard Cantonese — is the standard variant of the Cantonese (Yuet) language. It is spoken natively in and around the cities of Guangzhou, Hong Kong, and Macau in Southern China. Standard Cantonese is the de facto official language of Hong Kong and Macau, and a… …   Wikipedia

  • Time-division multiplexing — (TDM) is a type of digital or (rarely) analog multiplexing in which two or more signals or bit streams are transferred apparently simultaneously as sub channels in one communication channel, but are physically taking turns on the channel. The… …   Wikipedia

  • Time in Australia —   UTC+08:00 …   Wikipedia

  • Coordinated Universal Time — UTC redirects here. For other uses, see UTC (disambiguation). Coordinated Universal Time (abbreviated UTC) is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”