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Symmetricom
Symmetricom, Inc. (NASDAQ: SYMM) (acquired by Microsemi in 2013, then acquired by Microchip in 2018) develops, manufactures, and supplies timekeeping technology to customers in industry and government worldwide that require extremely precise synchronization. Symmetricom products supported precise timing standards, including GPS-based timing, IEEE 1588 (PTP), Network Time Protocol (NTP), Synchronous Ethernet and Data Over Cable Service Interface Specifications (DOCSIS®) timing. Products included hydrogen masers, rubidium and cesium atomic standards, temperature and oven controlled crystal oscillators, miniature and chip scale atomic clocks, network time servers, network sync management systems, cable timekeeping solutions, telecom synchronization supply units (SSUs), and timing test sets. Symmetricom was one of the only two world’s commercial supplier of cesium atomic standards (atomic clocks) - the other one is Oscilloquartz, in Switzerland. By weighted average, Symmetrico ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsemi
Microsemi Corporation was an Aliso Viejo, California-based provider of semiconductor and system solutions for aerospace & defense, communications, data center and industrial markets. In February 2018, it was announced that Chandler, Arizona-based Microchip Technology was acquiring the company for over US$10 billion, pending regulatory approval. In May 2018, it was announced that Microchip had completed its acquisition of Microsemi. In August 2018, Microchip discovered that Microsemi shipped large orders to distributors on discount before the closing of the acquisition and had a culture of excessive extravagance, casting some doubt on the future prospect of the acquisition. History 1959 to 1970: Early years Microsemi was founded in February 1959 in Culver City, California as MicroSemiconductor. It incorporated in Delaware on September 27, 1960. A trade catalog and price lists from this early period can be found at the Smithsonian Institution. In March 1963, A. Feldon repre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Maser
A hydrogen maser, also known as hydrogen frequency standard, is a specific type of maser that uses the intrinsic properties of the hydrogen atom to serve as a precision frequency reference. Both the proton and electron of a hydrogen atom have spins. The atom has a higher energy if both are spinning in the same direction, and a lower energy if they spin in opposite directions. The amount of energy needed to reverse the spin of the electron is equivalent to a photon at the frequency of , which corresponds to the 21 cm line in the hydrogen spectrum. Hydrogen masers are very complex devices and sell for as much as . There are two types to be distinguished: active and passive. In both types, a small storage bottle of molecular hydrogen, , leaks a controlled amount of gas into a discharge bulb. The molecules are dissociated in the discharge bulb into individual hydrogen atoms by an electric arc. This atomic hydrogen passes through a collimator then a magnetic state selector an ... [...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] |
Beijing, China
} Beijing ( ; ; ), alternatively romanized as Peking ( ), is the capital of the People's Republic of China. It is the center of power and development of the country. Beijing is the world's most populous national capital city, with over 21 million residents. It has an administrative area of , the third in the country after Guangzhou and Shanghai. It is located in Northern China, and is governed as a municipality under the direct administration of the State Council with 16 urban, suburban, and rural districts.Figures based on 2006 statistics published in 2007 National Statistical Yearbook of China and available online at archive. Retrieved 21 April 2009. Beijing is mostly surrounded by Hebei Province with the exception of neighboring Tianjin to the southeast; together, the three divisions form the Jingjinji megalopolis and the national capital region of China. Beijing is a global city and one of the world's leading centres for culture, diplomacy, politics, financ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuscaloosa, Alabama
Tuscaloosa ( ) is a city in and the seat of Tuscaloosa County in west-central Alabama, United States, on the Black Warrior River where the Gulf Coastal and Piedmont plains meet. Alabama's fifth-largest city, it had an estimated population of 101,129 in 2019. It was known as Tuskaloosa until the early 20th century. It is also known as ''"the Druid City"'' because of the numerous water oaks planted in its downtown streets since the 1840s. Incorporated on December 13, 1819, it was named after Tuskaloosa, the chief of a band of Muskogean-speaking people defeated by the forces of Spanish explorer Hernando de Soto in 1540 in the Battle of Mabila, in what is now central Alabama. It served as Alabama's capital city from 1826 to 1846. Tuscaloosa is the regional center of industry, commerce, healthcare and education for the area of west-central Alabama known as ''West Alabama;'' and the principal city of the Tuscaloosa Metropolitan Statistical Area, which includes Tuscaloosa, Ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beverly, Massachusetts
Beverly is a city in Essex County, Massachusetts, and a suburb of Boston. The population was 42,670 at the time of the 2020 United States Census. A resort, residential, and manufacturing community on the Massachusetts North Shore, Beverly includes Ryal Side, North Beverly, Montserrat, Beverly Farms and Prides Crossing. Beverly is a rival of Marblehead for the title of being the "birthplace of the U.S. Navy" History Native Americans inhabited what would become northeastern Massachusetts for thousands of years before European colonization of the Americas. At the time of contact in the early 1600s the area that would become Beverly was between an important Naumkeag settlement in present-day Salem and Agawam settlements on Cape Ann, with probable indigenous settlement sites at the mouth of the Bass River. During the early contact period virgin soil epidemics ravaged native populations, reducing the indigenous population within the present boundaries of Beverly from an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boulder, Colorado
Boulder is a home rule city that is the county seat and most populous municipality of Boulder County, Colorado, United States. The city population was 108,250 at the 2020 United States census, making it the 12th most populous city in Colorado. Boulder is the principal city of the Boulder, CO Metropolitan Statistical Area and an important part of the Front Range Urban Corridor. Boulder is located at the base of the foothills of the Rocky Mountains, at an elevation of above sea level. Boulder is northwest of the Colorado state capital of Denver. It is home of the main campus of the University of Colorado, the state's largest university. History On November 7, 1861, the Colorado General Assembly passed legislation to locate the University of Colorado in Boulder. On September 20, 1875, the first cornerstone was laid for the first building (Old Main) on the CU campus. The university officially opened on September 5, 1877. In 1907, Boulder adopted an anti- saloon ordi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BIPM
The International Bureau of Weights and Measures (french: Bureau international des poids et mesures, BIPM) is an intergovernmental organisation, through which its 59 member-states act together on measurement standards in four areas: chemistry, ionising radiation, physical metrology, and coordinated universal time. It is based in Saint-Cloud, Paris, France. The organisation has been referred to as IBWM (from its name in English) in older literature. Structure The BIPM is supervised by the International Committee for Weights and Measures (french: Comité international des poids et mesures, CIPM), a committee of eighteen members that meet normally in two sessions per year, which is in turn overseen by the General Conference on Weights and Measures (french: Conférence générale des poids et mesures, CGPM) that meets in Paris usually once every four years, consisting of delegates of the governments of the Member States and observers from the Associates of the CGPM. These organs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscilloquartz
Oscilloquartz, a company of ADVA Optical Networking, is a manufacturer of frequency sources, such as GPS& GLONASS receivers or caesium clocks for telecommunications applications and has been producing similar products for about 60 years. It also providers synchronization solutions for turnkey synchronization projects in e.g. PDH, SDH, SONET and all kind of mobile telecom networks e.g. GSM, X-CDMA, TETRA, 2.xG, 3G, 4G, UMTS, WiMAX. It also offers a wide range of technology, including its proprietary SyncView management software and including, as SyncView agents or embedded solutions, Q3, SNMP, TL1 interfaces. It also manufactures a range of products including single oven and double oven oscillators, targeted at the synchronisation of mobile base stations and other telecommunication equipment. The company headquarters is in Saint-Blaise, Switzerland. History * Oscilloquartz began its operations as a department of Ebauches SA in 1949, during the pioneering days of time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecom Synchronization
Many services running on modern digital telecommunications networks require accurate synchronization for correct operation. For example, if telephone exchanges are not synchronized, then bit slips will occur and degrade performance. Telecommunication networks rely on the use of highly accurate primary reference clocks which are distributed network-wide using synchronization links and synchronization supply units. Ideally, clocks in a telecommunications network are synchronous, controlled to run at identical rates, or at the same mean rate with a fixed relative phase displacement, within a specified limited range. However, they may be mesochronous in practice. In common usage, mesochronous networks are often described as ''synchronous''. Components Primary reference clock (PRC) Modern telecommunications networks use highly accurate primary master clocks that must meet the international standards requirement for long term frequency accuracy better than 1 part in 1011. To get th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Server
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience. Time is often referred to as a fourth dimension, along with three spatial dimensions. Time has long been an important subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. 108 pages. Time in physics is operationally defined as "what a clock reads". The physical nature of time is addresse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oven Controlled Oscillator
A crystal oven is a temperature-controlled chamber used to maintain the quartz crystal in electronic crystal oscillators at a constant temperature, in order to prevent changes in the frequency due to variations in ambient temperature. An oscillator of this type is known as an ''oven-controlled crystal oscillator'' (OCXO, where "XO" is an old abbreviation for "crystal oscillator".) This type of oscillator achieves the highest frequency stability possible with a crystal. They are typically used to control the frequency of radio transmitters, cellular base stations, military communications equipment, and for precision frequency measurement. Description Quartz crystals are widely used in electronic oscillators to precisely control the frequency produced. The frequency at which a quartz crystal resonator vibrates depends on its physical dimensions. A change in temperature causes the quartz to expand or contract due to thermal expansion, changing the frequency of the signal produc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
