subject+patent+information

- information in abstracts

- abstract information

- analysis of invention

SUBJECT AREA: Broadcasting, Electronics and information technology, Recording, Telecommunications

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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.

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SUBJECT AREA: Architecture and building, Automotive engineering, Electricity, Electronics and information technology, Metallurgy, Photography, film and optics, Public utilities, Recording, Telecommunications

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He was the son of Samuel Edison, who was in the timber business. His schooling was delayed due to scarlet fever until 1855, when he was 8½ years old, but he was an avid reader. By the age of 14 he had a job as a newsboy on the railway from Port Huron to Detroit, a distance of sixty-three miles (101 km). He worked a fourteen-hour day with a stopover of five hours, which he spent in the Detroit Free Library. He also sold sweets on the train and, later, fruit and vegetables, and was soon making a profit of $20 a week. He then started two stores in Port Huron and used a spare freight car as a laboratory. He added a hand-printing press to produce 400 copies weekly of The Grand Trunk Herald, most of which he compiled and edited himself. He set himself to learn telegraphy from the station agent at Mount Clements, whose son he had saved from being run over by a freight car.

At the age of 16 he became a telegraphist at Port Huron. In 1863 he became railway telegraphist at the busy Stratford Junction of the Grand Trunk Railroad, arranging a clock with a notched wheel to give the hourly signal which was to prove that he was awake and at his post! He left hurriedly after failing to hold a train which was nearly involved in a head-on collision. He usually worked the night shift, allowing himself time for experiments during the day. His first invention was an arrangement of two Morse registers so that a high-speed input could be decoded at a slower speed. Moving from place to place he held many positions as a telegraphist. In Boston he invented an automatic vote recorder for Congress and patented it, but the idea was rejected. This was the first of a total of 1180 patents that he was to take out during his lifetime. After six years he resigned from the Western Union Company to devote all his time to invention, his next idea being an improved ticker-tape machine for stockbrokers. He developed a duplex telegraphy system, but this was turned down by the Western Union Company. He then moved to New York.

Edison found accommodation in the battery room of Law's Gold Reporting Company, sleeping in the cellar, and there his repair of a broken transmitter marked him as someone of special talents. His superior soon resigned, and he was promoted with a salary of $300 a month. Western Union paid him $40,000 for the sole rights on future improvements on the duplex telegraph, and he moved to Ward Street, Newark, New Jersey, where he employed a gathering of specialist engineers. Within a year, he married one of his employees, Mary Stilwell, when she was only 16: a daughter, Marion, was born in 1872, and two sons, Thomas and William, in 1876 and 1879, respectively.

He continued to work on the automatic telegraph, a device to send out messages faster than they could be tapped out by hand: that is, over fifty words per minute or so. An earlier machine by Alexander Bain worked at up to 400 words per minute, but was not good over long distances. Edison agreed to work on improving this feature of Bain's machine for the Automatic Telegraph Company (ATC) for $40,000. He improved it to a working speed of 500 words per minute and ran a test between Washington and New York. Hoping to sell their equipment to the Post Office in Britain, ATC sent Edison to England in 1873 to negotiate. A 500-word message was to be sent from Liverpool to London every half-hour for six hours, followed by tests on 2,200 miles (3,540 km) of cable at Greenwich. Only confused results were obtained due to induction in the cable, which lay coiled in a water tank. Edison returned to New York, where he worked on his quadruplex telegraph system, tests of which proved a success between New York and Albany in December 1874. Unfortunately, simultaneous negotiation with Western Union and ATC resulted in a lawsuit.

Alexander Graham Bell was granted a patent for a telephone in March 1876 while Edison was still working on the same idea. His improvements allowed the device to operate over a distance of hundreds of miles instead of only a few miles. Tests were carried out over the 106 miles (170 km) between New York and Philadelphia. Edison applied for a patent on the carbon-button transmitter in April 1877, Western Union agreeing to pay him $6,000 a year for the seventeen-year duration of the patent. In these years he was also working on the development of the electric lamp and on a duplicating machine which would make up to 3,000 copies from a stencil. In 1876–7 he moved from Newark to Menlo Park, twenty-four miles (39 km) from New York on the Pennsylvania Railway, near Elizabeth. He had bought a house there around which he built the premises that would become his "inventions factory". It was there that he began the use of his 200- page pocket notebooks, each of which lasted him about two weeks, so prolific were his ideas. When he died he left 3,400 of them filled with notes and sketches.

Late in 1877 he applied for a patent for a phonograph which was granted on 19 February 1878, and by the end of the year he had formed a company to manufacture this totally new product. At the time, Edison saw the device primarily as a business aid rather than for entertainment, rather as a dictating machine. In August 1878 he was granted a British patent. In July 1878 he tried to measure the heat from the solar corona at a solar eclipse viewed from Rawlins, Wyoming, but his "tasimeter" was too sensitive.

Probably his greatest achievement was "The Subdivision of the Electric Light" or the "glow bulb". He tried many materials for the filament before settling on carbon. He gave a demonstration of electric light by lighting up Menlo Park and inviting the public. Edison was, of course, faced with the problem of inventing and producing all the ancillaries which go to make up the electrical system of generation and distribution-meters, fuses, insulation, switches, cabling—even generators had to be designed and built; everything was new. He started a number of manufacturing companies to produce the various components needed.

In 1881 he built the world's largest generator, which weighed 27 tons, to light 1,200 lamps at the Paris Exhibition. It was later moved to England to be used in the world's first central power station with steam engine drive at Holborn Viaduct, London. In September 1882 he started up his Pearl Street Generating Station in New York, which led to a worldwide increase in the application of electric power, particularly for lighting. At the same time as these developments, he built a 1,300yd (1,190m) electric railway at Menlo Park.

On 9 August 1884 his wife died of typhoid. Using his telegraphic skills, he proposed to 19-year-old Mina Miller in Morse code while in the company of others on a train. He married her in February 1885 before buying a new house and estate at West Orange, New Jersey, building a new laboratory not far away in the Orange Valley.

Edison used direct current which was limited to around 250 volts. Alternating current was largely developed by George Westinghouse and Nicola Tesla, using transformers to step up the current to a higher voltage for long-distance transmission. The use of AC gradually overtook the Edison DC system.

In autumn 1888 he patented a form of cinephotography, the kinetoscope, obtaining film-stock from George Eastman. In 1893 he set up the first film studio, which was pivoted so as to catch the sun, with a hinged roof which could be raised. In 1894 kinetoscope parlours with "peep shows" were starting up in cities all over America. Competition came from the Latham Brothers with a screen-projection machine, which Edison answered with his "Vitascope", shown in New York in 1896. This showed pictures with accompanying sound, but there was some difficulty with synchronization. Edison also experimented with captions at this early date.

In 1880 he filed a patent for a magnetic ore separator, the first of nearly sixty. He bought up deposits of low-grade iron ore which had been developed in the north of New Jersey. The process was a commercial success until the discovery of iron-rich ore in Minnesota rendered it uneconomic and uncompetitive. In 1898 cement rock was discovered in New Village, west of West Orange. Edison bought the land and started cement manufacture, using kilns twice the normal length and using half as much fuel to heat them as the normal type of kiln. In 1893 he met Henry Ford, who was building his second car, at an Edison convention. This started him on the development of a battery for an electric car on which he made over 9,000 experiments. In 1903 he sold his patent for wireless telegraphy "for a song" to Guglielmo Marconi.

In 1910 Edison designed a prefabricated concrete house. In December 1914 fire destroyed three-quarters of the West Orange plant, but it was at once rebuilt, and with the threat of war Edison started to set up his own plants for making all the chemicals that he had previously been buying from Europe, such as carbolic acid, phenol, benzol, aniline dyes, etc. He was appointed President of the Navy Consulting Board, for whom, he said, he made some forty-five inventions, "but they were pigeonholed, every one of them". Thus did Edison find that the Navy did not take kindly to civilian interference.

In 1927 he started the Edison Botanic Research Company, founded with similar investment from Ford and Firestone with the object of finding a substitute for overseas-produced rubber. In the first year he tested no fewer than 3,327 possible plants, in the second year, over 1,400, eventually developing a variety of Golden Rod which grew to 14 ft (4.3 m) in height. However, all this effort and money was wasted, due to the discovery of synthetic rubber.

In October 1929 he was present at Henry Ford's opening of his Dearborn Museum to celebrate the fiftieth anniversary of the incandescent lamp, including a replica of the Menlo Park laboratory. He was awarded the Congressional Gold Medal and was elected to the American Academy of Sciences. He died in 1931 at his home, Glenmont; throughout the USA, lights were dimmed temporarily on the day of his funeral.

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SUBJECT AREA: Broadcasting, Electronics and information technology, Telecommunications

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Hartley obtained his BA in 1909 from the University of Utah, then gained a Rhodes Scholarship to Oxford University, England. After obtaining a further BA and a BSc in 1912 and 1913, respectively, he returned to the USA and took a job with the Western Electric Laboratories of the Bell Telephone Company, where he was in charge of radio-receiver development. In 1915 he invented the Hartley oscillator, analogous to that invented by Colpitts. Subsequently he worked on carrier telephony at Western Electric and then at Bell Laboratories. There he concen-trated on information theory, building on the pioneering work of Nyquist, in 1926 publishing his law that related information capacity, frequency bandwidth and time. Forced to give up work in 1929 due to ill health, he returned to Bell in 1939 as a consultant on transmission problems. During the Second World War he worked on various projects, including the use of servo-mechanisms for radar and fire control, and finally retired in 1950.

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SUBJECT AREA: Recording

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He graduated from the Dover Academy (Delaware) in 1882 and was apprenticed in a machine-repair firm in Philadelphia and studied in evening classes at the Spring Garden Institute. In 1888 he took employment in a small Philadelphia machine shop owned by Andrew Scull, specializing in repair and bookbinding machinery. After travels in the western part of the US, in 1891 he became a partner in Scull \& Johnson, Manufacturing Machinists, and established a further company, the New Jersey Wire Stitching Machine Company. He bought out Andrew Scull's interest in October 1894 (the last instalment being paid in 1897) and became an independent general machinist. In 1896 he had perfected a spring motor for the Berliner flat-disc gramophone, and he started experimenting with a more direct method of recording in a spiral groove: that of cutting in wax. Co-operation with Berliner eventually led to the incorporation of the Victor Talking Machine Company in 1901. The innumerable court cases stemming from the fact that so many patents for various elements in sound recording and reproduction were in very many hands were brought to an end in 1903 when Johnson was material in establishing cross-licencing agreements between Victor, Columbia Graphophone and Edison to create what is known as a patent pool. Early on, Johnson had a thorough experience in all matters concerning the development and manufacture of both gramophones and records. He made and patented many major contributions in all these fields, and his approach was very business-like in that the contribution to cost of each part or process was always a decisive factor in his designs. This attitude was material in his consulting work for the sister company, the Gramophone Company, in London before it set up its own factories in 1910. He had quickly learned the advantages of advertising and of providing customers with durable equipment and records. This motivation was so strong that Johnson set up a research programme for determining the cause of wear in records. It turned out to depend on groove profile, and from 1911 one particular profile was adhered to and processes for transforming the grooves of valuable earlier records were developed. Without precise measuring instruments, he used the durability as the determining factor. Johnson withdrew more and more to the role of manager, and the Victor Talking Machine Company gained such a position in the market that the US anti-trust legislation was used against it. However, a generation change in the Board of Directors and certain erroneous decisions as to product line started a decline, and in February 1926 Johnson withdrew on extended sick leave: these changes led to the eventual sale of Victor. However, Victor survived due to the advent of radio and the electrification of replay equipment and became a part of Radio Corporation of America. In retirement Johnson took up various activities in the arts and sciences and financially supported several projects; his private yacht was used in 1933 in work with the Smithsonian Institution on a deep-sea hydrographie and fauna-collecting expedition near Puerto Rico.

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SUBJECT AREA: Electronics and information technology, Recording

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At the age of 23, Eisler obtained a Diploma in Engineering from the Technical University of Vienna. Because of the growing Nazi influence in Austria, he then accepted a post with the His Master's Voice (HMV) agents in Belgrade, where he worked on the problems of radio reception and sound transmission in railway trains. However, he soon returned to Vienna to found a weekly radio journal and file patents on graphical sound recording (for which he received a doctorate) and on a system of stereoscopic television based on lenticular vertical scanning.

In 1936 he moved to England and sold the TV patent to Marconi for £250. Unable to find a job, he carried out experiments in his rooms in a Hampstead boarding-house; after making circuits using strip wires mounted on bakelite sheet, he filed his first printed-circuit patent that year. He then tried to find ways of printing the circuits, but without success. Obtaining a post with Odeon Theatres, he invented a sound-level control for films and devised a mirror-drum continuous-film projector, but with the outbreak of war in 1939, when the company was evacuated, he chose to stay in London and was interned for a while. Released in 1941, he began work with Henderson and Spalding, a firm of lithographic printers, to whom he unwittingly assigned all future patents for the paltry sum of £1. In due course he perfected a means of printing conducting circuits and on 3 February 1943 he filed three patents covering the process. The British Ministry of Defence rejected the idea, considering it of no use for military equipment, but after he had demonstrated the technique to American visitors it was enthusiastically taken up in the US for making proximity fuses, of which many millions were produced and used for the war effort. Subsequently the US Government ruled that all air-borne electronic circuits should be printed.

In the late 1940s the Instrument Department of Henderson and Spalding was split off as Technograph Printed Circuits Ltd, with Eisler as Technical Director. In 1949 he filed a further patent covering a multilayer system; this was licensed to Pye and the Telegraph Condenser Company. A further refinement, patented in the 1950s, the use of the technique for telephone exchange equipment, but this was subsequently widely infringed and although he negotiated licences in the USA he found it difficult to license his ideas in Europe. In the UK he obtained finance from the National Research and Development Corporation, but they interfered and refused money for further development, and he eventually resigned from Technograph. Faced with litigation in the USA and open infringement in the UK, he found it difficult to establish his claims, but their validity was finally agreed by the Court of Appeal (1969) and the House of Lords (1971).

As a freelance inventor he filed many other printed-circuit patents, including foil heating films and batteries. When his Patent Agents proved unwilling to fund the cost of filing and prosecuting Complete Specifications he set up his own company, Eisler Consultants Ltd, to promote food and space heating, including the use of heated cans and wallpaper! As Foil Heating Ltd he went into the production of heating films, the process subsequently being licensed to Thermal Technology Inc. in California.

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SUBJECT AREA: Electronics and information technology, Telecommunications

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At the age of 8 Lodge entered Newport Grammar School, and in 1863–5 received private education at Coombs in Suffolk. He then returned to Staffordshire, where he assisted his father in the potteries by working as a book-keeper. Whilst staying with an aunt in London in 1866–7, he attended scientific lectures and became interested in physics. As a result of this and of reading copies of English Mechanic magazine, when he was back home in Hanley he began to do experiments and attended the Wedgewood Institute. Returning to London c. 1870, he studied initially at the Royal College of Science and then, from 1874, at University College, London (UCL), at the same time attending lectures at the Royal Institution.

In 1875 he obtained his BSc, read a paper to the British Association on "Nodes and loops in chemical formulae" and became a physics demonstrator at UCL. The following year he was appointed a physics lecturer at Bedford College, completing his DSc in 1877. Three years later he became Assistant Professor of Mathematics at UCL, but in 1881, after only two years, he accepted the Chair of Experimental Physics at the new University College of Liverpool. There began a period of fruitful studies of electricity and radio transmission and reception, including development of the lightning conductor, discovery of the "coherent" effect of sparks and improvement of Branly's coherer, and, in 1894, what is said to be the first public demonstration of the transmission and reception (using a coherer) of wireless telegraphy, from Lewis's department store to the clock tower of Liverpool University's Victoria Building. On 10 May 1897 he filed a patent for selective tuning by self-in-ductance; this was before Marconi's first patent was actually published and its priority was subsequently upheld.

In 1900 he became the first Principal of the new University of Birmingham, where he remained until his retirement in 1919. In his later years he was increasingly interested in psychical research.

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See also: Hertz, Heinrich Rudolph

SUBJECT AREA: Broadcasting, Electronics and information technology, Telecommunications

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Marconi was educated in physics at Leghorn and at Bologna University. An avid experimenter, he worked in his parents' attic and, almost certainly aware of the recent work of Hertz and others, soon improved the performance of coherers and spark-gap transmitters. He also discovered for himself the use of earthing and of elevated metal plates as aerials. In 1895 he succeeded in transmitting telegraphy over a distance of 2 km (1¼ miles), but the Italian Telegraph authority rejected his invention, so in 1896 he moved to England, where he filed the first of many patents. There he gained the support of the Chief Engineer of the Post Office, and by the following year he had achieved communication across the Bristol Channel.

The British Post Office was also slow to take up his work, so in 1897 he formed the Wireless Telegraph \& Signal Company to work independently. In 1898 he sold some equipment to the British Army for use in the Boer War and established the first permanent radio link from the Isle of Wight to the mainland. In 1899 he achieved communication across the English Channel (a distance of more than 31 miles or 50 km), the construction of a wireless station at Spezia, Italy, and the equipping of two US ships to report progress in the America's Cup yacht race, a venture that led to the formation of the American Marconi Company. In 1900 he won a contract from the British Admiralty to sell equipment and to train operators. Realizing that his business would be much more successful if he could offer his customers a complete radio-communication service (known today as a "turnkey" deal), he floated a new company, the Marconi International Marine Communications Company, while the old company became the Marconi Wireless Telegraph Company.

His greatest achievement occurred on 12 December 1901, when Morse telegraph signals from a transmitter at Poldhu in Cornwall were received at St John's, Newfoundland, a distance of some 2,100 miles (3,400 km), with the use of an aerial flown by a kite. As a result of this, Marconi's business prospered and he became internationally famous, receiving many honours for his endeavours, including the Nobel Prize for Physics in 1909. In 1904, radio was first used to provide a daily bulletin at sea, and in 1907 a transatlantic wireless telegraphy service was inaugurated. The rescue of 1,650 passengers from the shipwreck of SS Republic in 1909 was the first of many occasions when wireless was instrumental in saving lives at sea, most notable being those from the Titanic on its maiden voyage in April 1912; more lives would have been saved had there been sufficient lifeboats. Marconi was one of those who subsequently pressed for greater safety at sea. In 1910 he demonstrated the reception of long (8 km or 5 miles) waves from Ireland in Buenos Aires, but after the First World War he began to develop the use of short waves, which were more effectively reflected by the ionosphere. By 1918 the first link between England and Australia had been established, and in 1924 he was awarded a Post Office contract for short-wave communication between England and the various parts of the British Empire.

With his achievements by then recognized by the Italian Government, in 1915 he was appointed Radio-Communications Adviser to the Italian armed forces, and in 1919 he was an Italian delegate to the Paris Peace Conference. From 1921 he lived on his yacht, the Elettra, and although he joined the Fascist Party in 1923, he later had reservations about Mussolini.

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SUBJECT AREA: Broadcasting, Electronics and information technology

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Zworykin studied engineering at the Institute of Technology in St Petersburg under Boris Rosing, assisting the latter with his early experiments with television. After graduating in 1912, he spent a time doing X-ray research at the Collège de France in Paris before returning to join the Russian Marconi Company, initially in St Petersburg and then in Moscow. On the outbreak of war in 1917, he joined the Russian Army Signal Corps, but when the war ended in the chaos of the Revolution he set off on his travels, ending up in the USA, where he joined the Westinghouse Corporation. There, in 1923, he filed the first of many patents for a complete system of electronic television, including one for an all-electronic scanning pick-up tube that he called the iconoscope. In 1924 he became a US citizen and invented the kinescope, a hard-vacuum cathode ray tube (CRT) for the display of television pictures, and the following year he patented a camera tube with a mosaic of photoelectric elements and gave a demonstration of still-picture TV. In 1926 he was awarded a PhD by the University of Pittsburgh and in 1928 he was granted a patent for a colour TV system.

In 1929 he embarked on a tour of Europe to study TV developments; on his return he joined the Radio Corporation of America (RCA) as Director of the Electronics Research Group, first at Camden and then Princeton, New Jersey. Securing a budget to develop an improved CRT picture tube, he soon produced a kinescope with a hard vacuum, an indirectly heated cathode, a signal-modulation grid and electrostatic focusing. In 1933 an improved iconoscope camera tube was produced, and under his direction RCA went on to produce other improved types of camera tube, including the image iconoscope, the orthicon and image orthicon and the vidicon. The secondary-emission effect used in many of these tubes was also used in a scintillation radiation counter. In 1941 he was responsible for the development of the first industrial electron microscope, but for most of the Second World War he directed work concerned with radar, aircraft fire-control and TV-guided missiles.

After the war he worked for a time on high-speed memories and medical electronics, becoming Vice-President and Technical Consultant in 1947. He "retired" from RCA and was made an honorary vice-president in 1954, but he retained an office and continued to work there almost up until his death; he also served as Director of the Rockefeller Institute for Medical Research from 1954 until 1962.

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See also: Baird, John Logie; Farnsworth, Philo Taylor; Jenkins, Charles Francis

SUBJECT AREA: Horology

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John Harwood served an apprenticeship as a watch repairer in Bolton, and after service in the First World War he obtained a post with a firm of jewellers in Douglas, Isle of Man. He became interested in the self-winding wrist watch, not because of the convenience of not having to wind it, but because of its potential to keep the mainspring fully wound and to exclude dust and moisture from the watch movement. His experience at the bench had taught him that these were the most common factors to affect adversely the reliability of watches. Completely unaware of previous work in this area, in 1922 he started experimenting and two years later he had produced a serviceable model for which he was granted a patent in 1924. The watch operated on the pedometer principle, the mainspring being wound by a pivoted weight that oscillated in the watch case as a result of the motion of the arm. The hands of his watch were set by rotating the bezel surrounding the dial, dispensing with the usual winding/hand-setting stem which allowed dust and moisture to enter the watch case. He took the watch to Switzerland, but he was unable to persuade the watchmaking firms to produce it until he had secured independent finance to cover the cost of tooling. The Harwood Self-Winding Watch Company Ltd was set up in 1928 to market the watches, but although several thousand were produced the company became a victim of the slump and closed down in 1932. The first practical self-winding watch also operated on the pedometer principle and is attributed to Abraham-Louis Perrellet (1770). The method was refined by Breguet in France and by Recordon, who patented the device in England, but it proved troublesome and went out of fashion. There was a brief revival of interest in self-winding watches towards the end of the nineteenth century, but they never achieved great popularity until after the Second World War, when they used either self-winding mechanisms similar to that devised by Harwood or weights which rotated in the case.

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SUBJECT AREA: Broadcasting, Electronics and information technology

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After his initial engineering education at Kiev Polytechnic, Shoenberg went to London to undertake further studies at the Royal College of Science. In 1905 he returned to Russia and rose to become Chief Engineer of the Russian Wireless Telegraphy Company. He then returned to England, where he was a consultant in charge of the Patent Department and then joint General Manager of the Marconi Wireless Telegraphy Company (see Marconi). In 1929 he joined the Columbia Graphophone Company, but two years later this amalgamated with the Gramophone Company, by then known as His Master's voice (HMV), to form EMI (Electric and Musical Industries), a company in which the Radio Corporation of America (RCA) had a significant shareholding. Appointed Director of the new company's Research Laboratories in 1931, Shoenberg gathered together a team of highly skilled engineers, including Blumlein, Browne, Willans, McGee, Lubszynski, Broadway and White, with the objective of producing an all-electronic television system suitable for public broadcasting. A 150-line system had already been demonstrated using film as the source material; a photoemissive camera tube similar to Zworykin's iconoscope soon followed. With alternate demonstrations of the EMI system and the mechanical system of Baird arranged with the object of selecting a broadcast system for the UK, Shoenberg took the bold decision to aim for a 405-line "high-definition" standard, using interlaced scanning based on an RCA patent and further developed by Blumlein. This was so successful that it was formally adopted as the British standard in 1935 and regular broadcasts, the first in the world, began in 1937. It is a tribute to Shoenberg's vision and the skills of his team that this standard was to remain in use, apart from the war years, until finally superseded in 1985.

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See also: Baird, John Logie; Campbell-Swinton, Alan Archibald

SUBJECT AREA: Broadcasting, Electronics and information technology, Telecommunications

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Interested from childhood in anything mechanical, as a teenager Armstrong constructed a variety of wireless equipment in the attic of his parents' home, including spark-gap transmitters and receivers with iron-filing "coherer" detectors capable of producing weak Morse-code signals. In 1912, while still a student of engineering at Columbia University, he applied positive, i.e. regenerative, feedback to a Lee De Forest triode amplifier to just below the point of oscillation and obtained a gain of some 1,000 times, giving a receiver sensitivity very much greater than hitherto possible. Furthermore, by allowing the circuit to go into full oscillation he found he could generate stable continuous-waves, making possible the first reliable CW radio transmitter. Sadly, his claim to priority with this invention, for which he filed US patents in 1913, the year he graduated from Columbia, led to many years of litigation with De Forest, to whom the US Supreme Court finally, but unjustly, awarded the patent in 1934. The engineering world clearly did not agree with this decision, for the Institution of Radio Engineers did not revoke its previous award of a gold medal and he subsequently received the highest US scientific award, the Franklin Medal, for this discovery.

During the First World War, after some time as an instructor at Columbia University, he joined the US Signal Corps laboratories in Paris, where in 1918 he invented the superheterodyne, a major contribution to radio-receiver design and for which he filed a patent in 1920. The principle of this circuit, which underlies virtually all modern radio, TV and radar reception, is that by using a local oscillator to convert, or "heterodyne", a wanted signal to a lower, fixed, "intermediate" frequency it is possible to obtain high amplification and selectivity without the need to "track" the tuning of numerous variable circuits.

Returning to Columbia after the war and eventually becoming Professor of Electrical Engineering, he made a fortune from the sale of his patent rights and used part of his wealth to fund his own research into further problems in radio communication, particularly that of receiver noise. In 1933 he filed four patents covering the use of wide-band frequency modulation (FM) to achieve low-noise, high-fidelity sound broadcasting, but unable to interest RCA he eventually built a complete broadcast transmitter at his own expense in 1939 to prove the advantages of his system. Unfortunately, there followed another long battle to protect and exploit his patents, and exhausted and virtually ruined he took his own life in 1954, just as the use of FM became an established technique.

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SUBJECT AREA: Land transport, Mining and extraction technology, Railways and locomotives

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The son of a "coal viewer", Curr was brought up in the West Durham colliery district. In 1777 he went to the Duke of Norfolk's collieries at Sheffield, where in 1880 he was appointed Superintendent. There coal was conveyed underground in baskets on sledges: Curr replaced the wicker sledges with wheeled corves, i.e. small four-wheeled wooden wagons, running on "rail-roads" with cast-iron rails and hauled from the coal-face to the shaft bottom by horses. The rails employed hitherto had usually consisted of plates of iron, the flange being on the wheels of the wagon. Curr's new design involved flanges on the rails which guided the vehicles, the wheels of which were unflanged and could run on any hard surface. He appears to have left no precise record of the date that he did this, and surviving records have been interpreted as implying various dates between 1776 and 1787. In 1787 John Buddle paid tribute to the efficiency of the rails of Curr's type, which were first used for surface transport by Joseph Butler in 1788 at his iron furnace at Wingerworth near Chesterfield: their use was then promoted widely by Benjamin Outram, and they were adopted in many other English mines. They proved serviceable until the advent of locomotives demanded different rails.

In 1788 Curr also developed a system for drawing a full corve up a mine shaft while lowering an empty one, with guides to separate them. At the surface the corves were automatically emptied by tipplers. Four years later he was awarded a patent for using double ropes for lifting heavier loads. As the weight of the rope itself became a considerable problem with the increasing depth of the shafts, Curr invented the flat hemp rope, patented in 1798, which consisted of several small round ropes stitched together and lapped upon itself in winding. It acted as a counterbalance and led to a reduction in the time and cost of hoisting: at the beginning of a run the loaded rope began to coil upon a small diameter, gradually increasing, while the unloaded rope began to coil off a large diameter, gradually decreasing.

Curr's book The Coal Viewer (1797) is the earliest-known engineering work on railway track and it also contains the most elaborate description of a Newcomen pumping engine, at the highest state of its development. He became an acknowledged expert on construction of Newcomen-type atmospheric engines, and in 1792 he established a foundry to make parts for railways and engines.

Because of the poor financial results of the Duke of Norfolk's collieries at the end of the century, Curr was dismissed in 1801 despite numerous inventions and improvements which he had introduced. After his dismissal, six more of his patents were concerned with rope-making: the one he gained in 1813 referred to the application of flat ropes to horse-gins and perpendicular drum-shafts of steam engines. Curr also introduced the use of inclined planes, where a descending train of full corves pulled up an empty one, and he was one of the pioneers employing fixed steam engines for hauling. He may have resided in France for some time before his death.

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WK / PJGR

SUBJECT AREA: Broadcasting, Electronics and information technology, Photography, film and optics, Recording, Telecommunications

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De Forest was born into the family of a Congregational minister that moved to Alabama in 1879 when the father became President of a college for African-Americans; this was a position that led to the family's social ostracism by the white community. By the time he was 13 years old, De Forest was already a keen mechanical inventor, and in 1893, rejecting his father's plan for him to become a clergyman, he entered the Sheffield Scientific School of Yale University. Following his first degree, he went on to study the propagation of electromagnetic waves, gaining a PhD in physics in 1899 for his thesis on the "Reflection of Hertzian Waves from the Ends of Parallel Wires", probably the first US thesis in the field of radio.

He then joined the Western Electric Company in Chicago where he helped develop the infant technology of wireless, working his way up from a modest post in the production area to a position in the experimental laboratory. There, working alone after normal working hours, he developed a detector of electromagnetic waves based on an electrolytic device similar to that already invented by Fleming in England. Recognizing his talents, a number of financial backers enabled him to set up his own business in 1902 under the name of De Forest Wireless Telegraphy Company; he was soon demonstrating wireless telegraphy to interested parties and entering into competition with the American Marconi Company.

Despite the failure of this company because of fraud by his partners, he continued his experiments; in 1907, by adding a third electrode, a wire mesh, between the anode and cathode of the thermionic diode invented by Fleming in 1904, he was able to produce the amplifying device now known as the triode valve and achieve a sensitivity of radio-signal reception much greater than possible with the passive carborundum and electrolytic detectors hitherto available. Patented under the name Audion, this new vacuum device was soon successfully used for experimental broadcasts of music and speech in New York and Paris. The invention of the Audion has been described as the beginning of the electronic era. Although much development work was required before its full potential was realized, the Audion opened the way to progress in all areas of sound transmission, recording and reproduction. The patent was challenged by Fleming and it was not until 1943 that De Forest's claim was finally recognized.

Overcoming the near failure of his new company, the De Forest Radio Telephone Company, as well as unsuccessful charges of fraudulent promotion of the Audion, he continued to exploit the potential of his invention. By 1912 he had used transformer-coupling of several Audion stages to achieve high gain at radio frequencies, making long-distance communication a practical proposition, and had applied positive feedback from the Audion output anode to its input grid to realize a stable transmitter oscillator and modulator. These successes led to prolonged patent litigation with Edwin Armstrong and others, and he eventually sold the manufacturing rights, in retrospect often for a pittance.

During the early 1920s De Forest began a fruitful association with T.W.Case, who for around ten years had been working to perfect a moving-picture sound system. De Forest claimed to have had an interest in sound films as early as 1900, and Case now began to supply him with photoelectric cells and primitive sound cameras. He eventually devised a variable-density sound-on-film system utilizing a glow-discharge modulator, the Photion. By 1926 De Forest's Phonofilm had been successfully demonstrated in over fifty theatres and this system became the basis of Movietone. Though his ideas were on the right lines, the technology was insufficiently developed and it was left to others to produce a system acceptable to the film industry. However, De Forest had played a key role in transforming the nature of the film industry; within a space of five years the production of silent films had all but ceased.

In the following decade De Forest applied the Audion to the development of medical diathermy. Finally, after spending most of his working life as an independent inventor and entrepreneur, he worked for a time during the Second World War at the Bell Telephone Laboratories on military applications of electronics.

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KF / JW

SUBJECT AREA: Electronics and information technology

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In 1938, whilst working for a German electrical company, Flechsig filed a patent in which he described the use of an array of stretched parallel wires to control the landing of either one or three electron beams on separate red, green and blue phosphor stripes within a single cathode ray tube. Whilst the single-beam arrangement required subsidiary deflection to alternate the beam landing angle, the three-beam version effectively used the wires to "mask" the landing of the electron beams so that each one only illuminated the relevant colour phosphor stripes. Although not developed at the time, the concept anticipated the subsequent invention of the shadowmask tube by RCA in the early 1950s and, even more closely, the development of the Sony Trinitron some years later.

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See also: Baird, John Logie; Goldmark, Peter Carl

SUBJECT AREA: Electronics and information technology, Recording

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He developed recording equipment for. the Crystallate Gramophone Company, becoming Chief Recording Engineer at Decca when Crystallate was taken over. Eventually he was made Technical Director of Decca Record Company Ltd, a position he held until 1980. The developments of good cutterheads accelerated due to contract work for the armed services during the Second World War, because an extended frequency range was needed. This necessitated the solution of the problem of surface noise, and the result became known publicly as the ffrr system. The experience gained enabled Haddy to pioneer European Long Play recording. Haddy started development of a practical stereo record system within the Decca group, and for economic reasons he eventually chose a solution developed outside his direct surveillance by Teldec. The foresight of Decca made the company an equal partner in the standards discussions during the late 1950s, when it was decided to use the American 45/45 system, which utilized the two side walls of the groove. The same foresight had led Decca to record their repertoire in stereo from 1954 in order to prepare for any commercialized distribution system. In 1967 Haddy also became responsible for cassette manufacture, which meant organizing the logistics of a tape-duplication plant.

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