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Location Image CS1 [1] 1969 Cs 7 ... Caesium Beam Atomic Clock [18] [19] Cs Hong Kong Observatory; Tsim Sha Tsui, Hong Kong ...
The term is an acronym for microwave amplification by stimulated emission of radiation. Nikolay Basov , Alexander Prokhorov and Joseph Weber introduced the concept of the maser in 1952, and Charles H. Townes , James P. Gordon , and Herbert J. Zeiger built the first maser at Columbia University in 1953.
The core of the traditional radio frequency atomic clock is a tunable microwave cavity containing a gas. In a hydrogen maser clock the gas emits microwaves (the gas mases) on a hyperfine transition, the field in the cavity oscillates, and the cavity is tuned for maximum microwave amplitude. Alternatively, in a caesium or rubidium clock, the ...
Microwave signals are normally limited to the line of sight, so long-distance transmission using these signals requires a series of repeaters forming a microwave relay network. It is possible to use microwave signals in over-the-horizon communications using tropospheric scatter , but such systems are expensive and generally used only in ...
A clock or chronometer is a device that measures and displays time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, and the year. Devices operating on several physical processes have been used over the millennia.
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Monolithic microwave integrated circuit, or MMIC (sometimes pronounced "mimic"), is a type of integrated circuit (IC) device that operates at microwave frequencies (300 MHz to 300 GHz). These devices typically perform functions such as microwave mixing , power amplification, low-noise amplification , and high-frequency switching.
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