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1 Poulsen, Valdemar
[br]b. 23 November 1869 Copenhagen, Denmarkd. 23 July 1942 Gentofte, Denmark[br]Danish engineer who developed practical magnetic recording and the arc generator for continuous radio waves.[br]From an early age he was absorbed by phenomena of physics to the exclusion of all other subjects, including mathematics. When choosing his subjects for the final three years in Borgedydskolen in Christianshavn (Copenhagen) before university, he opted for languages and history. At the University of Copenhagen he embarked on the study of medicine in 1889, but broke it off and was apprenticed to the machine firm of A/S Frichs Eftf. in Aarhus. He was employed between 1893 and 1899 as a mechanic and assistant in the laboratory of the Copenhagen Telephone Company KTAS. Eventually he advanced to be Head of the line fault department. This suited his desire for experiment and measurement perfectly. After the invention of the telegraphone in 1898, he left the laboratory and with responsible business people he created Aktieselskabet Telegrafonen, Patent Poulsen in order to develop it further, together with Peder Oluf Pedersen (1874– 1941). Pedersen brought with him the mathematical background which eventually led to his professorship in electronic engineering in 1922.The telegraphone was the basis for multinational industrial endeavours after it was demonstrated at the 1900 World's Exhibition in Paris. It must be said that its strength was also its weakness, because the telegraphone was unique in bringing sound recording and reproduction to the telephone field, but the lack of electronic amplifiers delayed its use outside this and the dictation fields (where headphones could be used) until the 1920s. However, commercial interest was great enough to provoke a number of court cases concerning patent infringement, in which Poulsen frequently figured as a witness.In 1903–4 Poulsen and Pedersen developed the arc generator for continuous radio waves which was used worldwide for radio transmitters in competition with Marconi's spark-generating system. The inspiration for this work came from the research by William Duddell on the musical arc. Whereas Duddell had proposed the use of the oscillations generated in his electric arc for telegraphy in his 1901 UK patent, Poulsen contributed a chamber of hydrogen and a transverse magnetic field which increased the efficiency remarkably. He filed patent applications on these constructions from 1902 and the first publication in a scientific forum took place at the International Electrical Congress in St Louis, Missouri, in 1904.In order to use continuous waves efficiently (the high frequency constituted a carrier), Poulsen developed both a modulator for telegraphy and a detector for the carrier wave. The modulator was such that even the more primitive spark-communication receivers could be used. Later Poulsen and Pedersen developed frequency-shift keying.The Amalgamated Radio-Telegraph Company Ltd was launched in London in 1906, combining the developments of Poulsen and those of De Forest Wireless Telegraph Syndicate. Poulsen contributed his English and American patents. When this company was liquidated in 1908, its assets were taken over by Det Kontinentale Syndikat for Poulsen Radio Telegrafi, A/S in Copenhagen (liquidated 1930–1). Some of the patents had been sold to C.Lorenz AG in Berlin, which was very active.The arc transmitting system was in use worldwide from about 1910 to 1925, and the power increased from 12 kW to 1,000 kW. In 1921 an exceptional transmitter rated at 1,800 kW was erected on Java for communications with the Netherlands. More than one thousand installations had been in use worldwide. The competing systems were initially spark transmitters (Marconi) and later rotary converters ( Westinghouse). Similar power was available from valve transmitters only much later.From c. 1912 Poulsen did not contribute actively to further development. He led a life as a well-respected engineer and scientist and served on several committees. He had his private laboratory and made experiments in the composition of matter and certain resonance phenomena; however, nothing was published. It has recently been suggested that Poulsen could not have been unaware of Oberlin Smith's work and publication in 1888, but his extreme honesty in technical matters indicates that his development was indeed independent. In the case of the arc generator, Poulsen was always extremely frank about the inspiration he gained from earlier developers' work.[br]Bibliography1899, British patent no. 8,961 (the first British telegraphone patent). 1903, British patent no. 15,599 (the first British arc-genera tor patent).His scientific publications are few, but fundamental accounts of his contribution are: 1900, "Das Telegraphon", Ann. d. Physik 3:754–60; 1904, "System for producing continuous oscillations", Trans. Int. El. Congr. St. Louis, Vol. II, pp. 963–71.Further ReadingA.Larsen, 1950, Telegrafonen og den Traadløse, Ingeniørvidenskabelige Skrifter no. 2, Copenhagen (provides a very complete, although somewhat confusing, account of Poulsen's contributions; a list of his patents is given on pp. 285–93).F.K.Engel, 1990, Documents on the Invention of Magnetic Re cor ding in 1878, New York: Audio Engineering Society, reprint no. 2,914 (G2) (it is here that doubt is expressed about whether Poulsen's ideas were developed independently).GB-N -
2 Broadcasting
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3 Electronics and information technology
See also: INDEX BY SUBJECT AREA[br]Byron, Ada AugustaNapier, JohnRiche, Gaspard-Clair-François-MarieSchickhard, WilhelmBiographical history of technology > Electronics and information technology
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4 Recording
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5 Telecommunications
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6 Smith, Oberlin
[br]b. 22 March 1840 Cincinnati, Ohio, USAd. 18 July 1926[br]American mechanical engineer, pioneer in experiments with magnetic recording.[br]Of English descent, Smith embarked on an education in mechanical engineering, graduating from West Jersey Academy, Bridgeton, New Jersey, in 1859. In 1863 he established a machine shop in Bridgeton, New Jersey, that became the Ferracute Machine Company in 1877, eventually specializing in the manufacture of presses for metalworking. He seems to have subscribed to design principles considered modern even in the 1990s, "always giving attention to the development of artistic form in combination with simplicity, and with massive strength where required" (bibliographic reference below). He was successful in his business, and developed and patented a large number of mechanical constructions.Inspired by the advent of the phonograph of Edison, in 1878 Smith obtained the tin-foil mechanical phonograph, analysed its shortcomings and performed some experiments in magnetic recording. He filed a caveat in the US Patent Office in order to be protected while he "reduced the invention to practice". However, he did not follow this trail. When there was renewed interest in practical sound recording and reproduction in 1888 (the constructions of Berliner and Bell \& Tainter), Smith published an account of his experiments in the journal Electrical World. In a corrective letter three weeks later it is clear that he was aware of the physical requirements for the interaction between magnetic coil and magnetic medium, but his publications also indicate that he did not as such obtain reproduction of recorded sound.Smith did not try to develop magnetic recording, but he felt it imperative that he be given credit for conceiving the idea of it. When accounts of Valdemar Poulsen's work were published in 1900, Smith attempted to prove some rights in the invention in the US Patent Office, but to no avail.He was a highly respected member of both his community and engineering societies, and in later life became interested in the anti-slavery cause that had also been close to the heart of his parents, as well as in the YMCA movement and in women's suffrage.[br]BibliographyApart from numerous technical papers, he wrote the book Press Working of Metals, 1896. His accounts on the magnetic recording experiments were "Some possible forms of phonograph", Electrical World (8 September 1888): 161 ff, and "Letter to the Editor", Electrical World (29 September 1888): 179.Further ReadingF.K.Engel, 1990, Documents on the Invention of Magnetic Recording in 1878, New York: Audio Engineering Society, Reprint no. 2,914 (G2) (a good overview of the material collected by the Oberlin Smith Society, Bridgeton, New Jersey, in particular as regards the recording experiments; it is here that it is doubted that Valdemar Poulsen developed his ideas independently).GB-N -
7 Forrester, Jay Wright
SUBJECT AREA: Electronics and information technology[br]b. 14 July 1918 Anselmo, Nebraska, USA[br]American electrical engineer and management expert who invented the magnetic-core random access memory used in most early digital computers.[br]Born on a cattle ranch, Forrester obtained a BSc in electrical engineering at the University of Nebraska in 1939 and his MSc at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts, where he remained to teach and carry out research. Becoming interested in computing, he established the Digital Computer Laboratory at MIT in 1945 and became involved in the construction of Whirlwind I, an early general-purpose computer completed in March 1951 and used for flight-simulation by the US Army Air Force. Finding the linear memories then available for storing data a major limiting factor in the speed at which computers were able to operate, he developed a three-dimensional store based on the binary switching of the state of small magnetic cores that could be addressed and switched by a matrix of wires carrying pulses of current. The machine used parallel synchronous fixed-point computing, with fifteen binary digits and a plus sign, i.e. 16 bits in all, and contained 5,000 vacuum tubes, eleven semiconductors and a 2 MHz clock for the arithmetic logic unit. It occupied a two-storey building and consumed 150kW of electricity. From his experience with the development and use of computers, he came to realize their great potential for the simulation and modelling of real situations and hence for the solution of a variety of management problems, using data communications and the technique now known as interactive graphics. His later career was therefore in this field, first at the MIT Lincoln Laboratory in Lexington, Massachusetts (1951) and subsequently (from 1956) as Professor at the Sloan School of Management at the Massachusetts Institute of Technology.[br]Principal Honours and DistinctionsNational Academy of Engineering 1967. George Washington University Inventor of the Year 1968. Danish Academy of Science Valdemar Poulsen Gold Medal 1969. Systems, Man and Cybernetics Society Award for Outstanding Accomplishments 1972. Computer Society Pioneer Award 1972. Institution of Electrical Engineers Medal of Honour 1972. National Inventors Hall of Fame 1979. Magnetics Society Information Storage Award 1988. Honorary DEng Nebraska 1954, Newark College of Engineering 1971, Notre Dame University 1974. Honorary DSc Boston 1969, Union College 1973. Honorary DPolSci Mannheim University, Germany. Honorary DHumLett, State University of New York 1988.Bibliography1951, "Data storage in three dimensions using magnetic cores", Journal of Applied Physics 20: 44 (his first description of the core store).Publications on management include: 1961, Industrial Dynamics, Cambridge, Mass.: MIT Press; 1968, Principles of Systems, 1971, Urban Dynamics, 1980, with A.A.Legasto \& J.M.Lyneis, System Dynamics, North Holland. 1975, Collected Papers, Cambridge, Mass.: MIT.Further ReadingK.C.Redmond \& T.M.Smith, Project Whirlwind, the History of a Pioneer Computer (provides details of the Whirlwind computer).H.H.Goldstine, 1993, The Computer from Pascal to von Neumann, Princeton University Press (for more general background to the development of computers).Serrell et al., 1962, "Evolution of computing machines", Proceedings of the Institute ofRadio Engineers 1,047.M.R.Williams, 1975, History of Computing Technology, London: Prentice-Hall.See also: Burks, Arthur Walter; Goldstine, Herman H.; Wilkes, Maurice Vincent; Williams, Sir Frederic CallandKF -
8 Pierce, John Robinson
[br]b. 27 March 1910 Des Moines, Iowa, USA[br]American scientist and communications engineer said to be the "father" of communication satellites.[br]From his high-school days, Pierce showed an interest in science and in science fiction, writing under the pseudonym of J.J.Coupling. After gaining Bachelor's, Master's and PhD degrees at the California Institute of Technology (CalTech) in Pasadena in 1933, 1934 and 1936, respectively, Pierce joined the Bell Telephone Laboratories in New York City in 1936. There he worked on improvements to the travelling-wave tube, in which the passage of a beam of electrons through a helical transmission line at around 7 per cent of the speed of light was made to provide amplification at 860 MHz. He also devised a new form of electrostatically focused electron-multiplier which formed the basis of a sensitive detector of radiation. However, his main contribution to electronics at this time was the invention of the Pierce electron gun—a method of producing a high-density electron beam. In the Second World War he worked with McNally and Shepherd on the development of a low-voltage reflex klystron oscillator that was applied to military radar equipment.In 1952 he became Director of Electronic Research at the Bell Laboratories' establishment, Murray Hill, New Jersey. Within two years he had begun work on the possibility of round-the-world relay of signals by means of communication satellites, an idea anticipated in his early science-fiction writings (and by Arthur C. Clarke in 1945), and in 1955 he published a paper in which he examined various possibilities for communications satellites, including passive and active satellites in synchronous and non-synchronous orbits. In 1960 he used the National Aeronautics and Space Administration 30 m (98 1/2 ft) diameter, aluminium-coated Echo 1 balloon satellite to reflect telephone signals back to earth. The success of this led to the launching in 1962 of the first active relay satellite (Telstar), which weighed 170 lb (77 kg) and contained solar-powered rechargeable batteries, 1,000 transistors and a travelling-wave tube capable of amplifying the signal 10,000 times. With a maximum orbital height of 3,500 miles (5,600 km), this enabled a variety of signals, including full bandwidth television, to be relayed from the USA to large receiving dishes in Europe.From 1971 until his "retirement" in 1979, Pierce was Professor of Electrical Engineering at CalTech, after which he became Chief Technologist at the Jet Propulsion Laboratories, also in Pasadena, and Emeritus Professor of Engineering at Stanford University.[br]Principal Honours and DistinctionsInstitute of Electrical and Electronics Engineers Morris N.Liebmann Memorial Award 1947; Edison Medal 1963; Medal of Honour 1975. Franklin Institute Stuart Ballantine Award 1960. National Medal of Science 1963. Danish Academy of Science Valdemar Poulsen Medal 1963. Marconi Award 1974. National Academy of Engineering Founders Award 1977. Japan Prize 1985. Arthur C.Clarke Award 1987. Honorary DEng Newark College of Engineering 1961. Honorary DSc Northwest University 1961, Yale 1963, Brooklyn Polytechnic Institute 1963. Editor, Proceedings of the Institute of Radio Engineers 1954–5.Bibliography23 October 1956, US patent no. 2,768,328 (his development of the travelling-wave tube, filed on 5 November 1946).1947, with L.M.Field, "Travelling wave tubes", Proceedings of the Institute of RadioEngineers 35:108 (describes the pioneering improvements to the travelling-wave tube). 1947, "Theory of the beam-type travelling wave tube", Proceedings of the Institution ofRadio Engineers 35:111. 1950, Travelling Wave Tubes.1956, Electronic Waves and Messages. 1962, Symbols, Signals and Noise.1981, An Introduction to Information Theory: Symbols, Signals and Noise: Dover Publications.1990, with M.A.Knoll, Signals: Revolution in Electronic Communication: W.H.Freeman.KF -
9 Yagi, Hidetsugu
[br]b. 28 January 1886 Osaka, Japand. January 1976 Osaka, Japan[br]Japanese engineer who, with his student Shintaro Uda, developed the directional ultra-high frequency (UHF) aerial array that bears his name.[br]Yagi studied engineering at Tokyo Imperial University (now Tokyo University), graduating in 1910. For the next four years he taught at Engineering High School in Sendai, Honshu, then in 1914 he was sent to study resonance phenomena under Barkhausen at Dresden University. When the First World War broke out he was touring Europe, so he travelled to London to study under Ambrose Fleming at University College, London. Continuing his travels, he then visited the USA, studying at Harvard under G.W. Pierce, before returning to his teaching post at Sendai Engineering High School, which in 1919 was absorbed into Tohoku University. There, in 1921, he obtained his doctorate, and some years later he was appointed Professor of Electrical Engineering. Having heard of the invention of the magnetron, he worked with a student, Kinjiro Okabe; in 1927 they produced microwave energy at a wavelength of a few tens of centimetres. However, he is best known for his development with another student, Shintaro Uda, of a directional, multi-element ultrahigh frequency aerial, which he demonstrated during a tour of the USA in 1928. During the Second World War Yagi worked on radar systems. After his retirement he became Professor Emeritus at Tohoku and Osaka universities and formed the Yagi Antenna Company.[br]Principal Honours and DistinctionsYagi received various honours, including the Japanese Cultural Order of Merit 1976, and the Valdemar Poulsen Gold Medal.Bibliography1928, "Beam transmission of ultra-short waves", Proceedings of the Institute of Radio Engineers 6:715 (describes the Yagi-Uda aerial).Further ReadingF.E.Terman, 1943, Radio Engineers' Handbook, New York: McGraw-Hill (provides a review of aerials, including the Yagi system).KF
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