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Atomichron
The Atomichron was the world's first commercial atomic clock, built by the National Company, Inc. of Malden, Massachusetts. It was also the first self-contained portable atomic clock and was a caesium standard The caesium standard is a primary frequency standard in which the Absorption (electromagnetic radiation), photon absorption by transitions between the two hyperfine level, hyperfine ground states of caesium-133 atoms is used to control the output ... clock. More than 50 clocks with the trademarked Atomichron name were produced. See also * Chip-scale atomic clock * Hoptroff London References External links A Brief History of the National Company, IncAtomichron: The Atomic Clock from Concept to Commercial Product {{physics-stub Atomic clocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Clock
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, \Delta \nu_\mathsf, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be when expressed in the unit Hz, which is equal to s−1. This definition is the basis for the system of International Atomic Time (TAI), which is maintained by an ensemble of atomic clocks around the world. The system of Coordinated Universal Time (UTC) that is the basis of civil time implements leap seconds to allo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Radio Company
The National Radio Company, headquartered in Malden, Massachusetts, United States, was an American manufacturer of radio equipment from 1914 to 1991. History The company was incorporated, in 1914, as the "National Toy Company", but by 1916 had included household appliances in their product range. This expansion led to the name change to the "National Company, Inc.". By 1923 the product line included toys, food mixers, and radio components. Radio components were to play an important part in the company's growth in the mid-1920s as they moved into the large scale manufacture of capacitors. It was at this time that two engineers from Harvard University, Fred H. Drake and Glen Browning, approached National to manufacture components to their specifications for a radio receiver of their own design. This relationship led to the production and sale of the "National Regenaformer" kit for home construction of the Browning-Drake design. The set was capable of tuning the standard AM broadcast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caesium Standard
The caesium standard is a primary frequency standard in which the Absorption (electromagnetic radiation), photon absorption by transitions between the two hyperfine level, hyperfine ground states of caesium-133 atoms is used to control the output frequency. The first caesium clock was built by Louis Essen in 1955 at the National Physical Laboratory, UK, National Physical Laboratory in the UK. and promoted worldwide by Gernot M. R. Winkler of the United States Naval Observatory. Caesium atomic clocks are one of the most accurate time and frequency standards, and serve as the primary standard for the definition of the second in the International System of Units (SI) (the modern form of the metric system). By definition, radiation produced by the transition between the two hyperfine ground states of caesium (in the absence of external influences such as the Earth's magnetic field) has a frequency, , of exactly . That value was chosen so that the caesium second equalled, to the limit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chip-scale Atomic Clock
A chip scale atomic clock (CSAC) is a compact, low-power atomic clock fabricated using techniques of microelectromechanical systems (MEMS) and incorporating a low-power semiconductor laser as the light source. The first CSAC physics package was demonstrated at NIST in 2003, based on an invention made in 2001. The work was funded by the US Department of Defense's Defense Advanced Research Projects Agency (DARPA) with the goal of developing a microchip-sized atomic clock for use in portable equipment. In military equipment it is expected to provide improved location and battlespace situational awareness for dismounted soldiers when the global positioning system is not available, but many civilian applications are also envisioned. Commercial manufacturing of these atomic clocks began in 2011. The CSAC, the world's smallest atomic clock, is 4 x 3.5 x 1 cm (1.5 x 1.4 x 0.4 inches) in size, weighs 35 grams, consumes only 115 mW of power, and can keep time to within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoptroff London
Hoptroff is a provider of distributed timing services, based in London, England. The company was previously a watch manufacturer based in London, England, known for its atomic clock and high accuracy watches. History Hoptroff was founded in 2010 as Hoptroff London by Richard Hoptroff, a physicist with the original intention of supplying smart mechanical watch movements to the industry. In 2012, the company incorporated Bluetooth Low Energy technology to its watches for the movement and sync with the mobile phones for configuration in order to display internet connected information. In April 2013, the company unveiled its first atomic timepiece in London, which conceptualized it as a new variety of time regulation devices in clocks and watches, that could be placed alongside the balance spring, quartz crystal and the pendulum. After the launch, the brand gained a reputation for the most accurate watch ever produced and was mentioned in several media outlets, such as New York Tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
