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Alan Dower Blumlein
Alan Dower Blumlein (29 June 1903 – 7 June 1942) was an English electronics engineer, notable for his many inventions in telecommunications, sound recording, stereophonic sound, television and radar. He received 128 patents and was considered one of the most significant engineers and inventors of his time. He died during World War II on 7 June 1942, aged 38, during the secret trial of an H2S airborne radar system then under development, when all on board the Halifax bomber in which he was flying were killed when it crashed at Welsh Bicknor in Herefordshire. Early life Alan Dower Blumlein was born on 29 June 1903 in Hampstead, London. His father, Semmy Blumlein, was a German-born naturalised British subject. Semmy was the son of Joseph Blumlein, a German of Jewish descent, and Philippine Hellmann, a French woman of German descent.Semmy Blumlein's father, Joseph B. Blumlein was Jewish, ''see Burns, p. 2'' Alan's mother, Jessie Dower, was Scottish, daughter of William Dower (bor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hampstead
Hampstead () is an area in London, which lies northwest of Charing Cross, and extends from Watling Street, the A5 road (Roman Watling Street) to Hampstead Heath, a large, hilly expanse of parkland. The area forms the northwest part of the London Borough of Camden, a borough in Inner London which for the purposes of the London Plan is designated as part of Central London. Hampstead is known for its intellectual, liberal, artistic, musical, and literary associations. It has some of the most expensive housing in the London area. Hampstead has more millionaires within its boundaries than any other area of the United Kingdom.Wade, David"Whatever happened to Hampstead Man?" ''The Daily Telegraph'', 8 May 2004 (retrieved 3 March 2016). History Toponymy The name comes from the Old English, Anglo-Saxon words ''ham'' and ''stede'', which means, and is a cognate of, the Modern English "homestead". To 1900 Early records of Hampstead can be found in a grant by King Ethelred the Unread ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Undergraduate Degree Classification
The British undergraduate degree classification system is a grading structure for undergraduate degrees or bachelor's degrees and integrated master's degrees in the United Kingdom. The system has been applied (sometimes with significant variations) in other countries and regions. History The classification system as currently used in the United Kingdom was developed in 1918. Honours were then a means to recognise individuals who demonstrated depth of knowledge or originality, as opposed to relative achievement in examination conditions. Concern exists about possible grade inflation. It is claimed that academics are under increasing pressure from administrators to award students good marks and grades with little regard for those students' actual abilities, in order to maintain their league table rankings. The percentage of graduates who receive a First (First Class Honours) has grown from 7% in 1997 to 26% in 2017, with the rate of growth sharply accelerating toward the end of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge Circuit
A bridge circuit is a topology of electrical circuitry in which two circuit branches (usually in parallel with each other) are "bridged" by a third branch connected between the first two branches at some intermediate point along them. The bridge was originally developed for laboratory measurement purposes and one of the intermediate bridging points is often adjustable when so used. Bridge circuits now find many applications, both linear and non-linear, including in instrumentation, filtering and power conversion. The best-known bridge circuit, the Wheatstone bridge, was invented by Samuel Hunter Christie and popularized by Charles Wheatstone, and is used for measuring resistance. It is constructed from four resistors, two of known values R1 and R3 (see diagram), one whose resistance is to be determined Rx, and one which is variable and calibrated R2. Two opposite vertices are connected to a source of electric current, such as a battery, and a galvanometer is connected across t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loading Coil
A loading coil or load coil is an inductor that is inserted into an electronic circuit to increase its inductance. The term originated in the 19th century for inductors used to prevent signal distortion in long-distance telegraph transmission cables. The term is also used for inductors in radio antennas, or between the antenna and its feedline, to make an electrically short antenna resonant at its operating frequency. The concept of loading coils was discovered by Oliver Heaviside in studying the problem of slow signalling speed of the first transatlantic telegraph cable in the 1860s. He concluded additional inductance was required to prevent amplitude and time delay distortion of the transmitted signal. The mathematical condition for distortion-free transmission is known as the Heaviside condition. Previous telegraph lines were overland or shorter and hence had less delay, and the need for extra inductance was not as great. Submarine communications cables are particularly sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wireless World
''Electronics World'' (''Wireless World'', founded in 1913, and in September 1984 renamed ''Electronics & Wireless World'') is a technical magazine in electronics and RF engineering aimed at professional design engineers. It is produced monthly in print and digital formats. The editorial content of ''Electronics World'' covers the full range of electronics and RF industry activities including technology, systems, components, design, development tools, software, networking, communications tools and instrumentation. It encompasses a range of issues in the electronics and RF industry, from design through to product implementation. The features are contributed by engineers and academics in the electronics industry. The circulation is split between electronic design engineers, senior managers, and R&D professionals within areas such as communications, manufacturing, education and training, IT, medical, power, oil and gas. History The Marconi Company published the first issue of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institution Of Electrical Engineers
The Institution of Electrical Engineers (IEE) was a British professional organisation of electronics, electrical, manufacturing, and Information Technology professionals, especially electrical engineers. It began in 1871 as the Society of Telegraph Engineers. In 2006, it changed its name to the Institution of Engineering and Technology (IET). Notable past presidents have included Lord Kelvin (1889), Sir Joseph Swan (1898) and Sebastian de Ferranti (1910–11). Notable chairmen include John M. M. Munro (1910–11). History The IEE was founded in 1871 as the Society of Telegraph Engineers, changed its name in 1880 to the Society of Telegraph Engineers and Electricians and changed to the Institution of Electrical Engineers in 1888. It was Incorporated by a Royal Charter in 1921. In 1988 the Institution of Electrical Engineers (IEE) merged with the Institution of Electronic and Radio Engineers (IERE), originally the British Institution of Radio Engineers (Brit IRE) founded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise Weighting
A noise weighting is a specific amplitude-vs.-frequency characteristic that is designed to allow subjectively valid measurement of noise. It emphasises the parts of the spectrum that are most important. Usually, noise means audible noise, in audio systems, broadcast systems or telephone circuits. In this case the weighting is sometimes referred to as Psophometric weighting, though this term is best avoided because, although strictly a general term, the word Psophometric is sometimes assumed to refer to a particular weighting used in telecommunications. A major use of noise weighting is in the measurement of residual noise in audio equipment, usually present as hiss or hum in quiet moments of programme material. The purpose of weighting here is to emphasise the parts of the audible spectrum that our ears perceive most readily, and attenuate the parts that contribute less to our perception of loudness, in order to get a measured figure that correlates well with subjective effect. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Response
In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and phase of the output as a function of input frequency. The frequency response is widely used in the design and analysis of systems, such as audio and control systems, where they simplify mathematical analysis by converting governing differential equations into algebraic equations. In an audio system, it may be used to minimize audible distortion by designing components (such as microphones, amplifiers and loudspeakers) so that the overall response is as flat (uniform) as possible across the system's bandwidth. In control systems, such as a vehicle's cruise control, it may be used to assess system stability, often through the use of Bode plots. Systems with a specific frequency response can be designed using analog and digital filters. The frequency response characterizes systems in the frequency domain, just as the impulse response characterizes systems in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a periodic function is sometimes called the amplitude. Definitions Peak amplitude & semi-amplitude For symmetric periodic waves, like sine waves, square waves or triangle waves ''peak amplitude'' and ''semi amplitude'' are the same. Peak amplitude In audio system measurements, telecommunications and others where the measurand is a signal that swings above and below a reference value but is not sinusoidal, peak amplitude is often used. If the reference is zero, this is the maximum absolute value of the signal; if the reference is a mean value (DC component), the peak amplitude is the maximu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Telephones And Cables
Standard Telephones and Cables Ltd (later STC plc) was a British manufacturer of telephone, telegraph, radio, telecommunications, and related equipment. During its history, STC invented and developed several groundbreaking new technologies including pulse-code modulation (PCM) and optical fibres. The company was founded in 1883 in London as International Western Electric by the Western Electric Company, shortly after Western Electric became the telephone equipment supplier for the American Telephone and Telegraph Company (AT&T) in the United States. In 1925, Western Electric divested itself of all foreign operations and sold International Western Electric to International Telephone and Telegraph (ITT), in part to thwart antitrust actions by the American government. In mid-1982, STC became an independent company and was listed on the London Stock Exchange; for a time it was a constituent of the FTSE 100 Index. It was bought by Nortel in 1991. History Early days The company was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Electric Company
The Western Electric Company was an American electrical engineering and manufacturing company officially founded in 1869. A wholly owned subsidiary of American Telephone & Telegraph for most of its lifespan, it served as the primary equipment manufacturer, supplier, and purchasing agent for the Bell System from 1881 to 1984 when it was dismantled. The company was responsible for many technological innovations as well as developments in industrial management. History In 1856, George Shawk, a craftsman and telegraph maker, purchased an electrical engineering business in Cleveland, Ohio. In January, 1869, Shawk had partnered with Enos M. Barton in the former Western Union repair shop of Cleveland, to manufacture burglar, fire alarms, and other electrical items. Both men were former Western Union employees. Shawk, was the Cleveland shop foreman and Barton, was a Rochester, New York telegrapher. During this Shawk and Barton partnership, one customer was an inventor sourcing parts and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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