Information about History Of Television
The History of television technology can be divided along two lines: those developments that depended upon both mechanical and electronic principles, and those which are purely electronic. From the latter descended all modern televisions, but these would not have been possible without discoveries and insights from the mechanical systems.
The word television is a hybrid word, created from both Greek and Latin. Tele- is Greek for "far", while -vision is from the Latin visio, meaning "vision" or "sight". It is often abbreviated as TV or the telly.
The origins of what would become today's television system can be traced back to the discovery of the photoconductivity of the element selenium by Willoughby Smith in 1873, and the invention of a scanning disk by Paul Gottlieb Nipkow in 1884.
German student Nipkow proposed and patented the first electromechanical television system in 1884. Nipkow's spinning disk design is credited with being the first television image rasterizer. Constantin Perskyi had coined the word television in a paper read to the International Electricity Congress at the International World Fair in Paris on August 25, 1900. Perskyi's paper reviewed the existing electromechanical technologies, mentioning the work of Nipkow and others. The photoconductivity of selenium and Nipkow's scanning disk were first joined for practical use in the electronic transmission of still pictures and photographs, and by the first decade of the 20th century halftone photographs were being transmitted by facsimile over telegraph and telephone lines as a newspaper service.
However, it wasn't until 1907 that developments in amplification tube technology made the design practical.[1] The first demonstration of the instantaneous transmission of still duotone images was by Georges Rignoux and A. Fournier in Paris in 1909, using a rotating mirror-drum as the scanner, and a matrix of 64 selenium cells as the receiver.[2]
In 1911, Boris Rosing and his student Vladimir Kosma Zworykin created a television system that used a mechanical mirror-drum scanner to transmit, in Zworykin's words, "very crude images" over wires to the electronic Braun tube (cathode ray tube) in the receiver. Moving images were not possible because, in the scanner, "the sensitivity was not enough and the selenium cell was very laggy".
On March 25, 1925, Scottish inventor John Logie Baird gave a demonstration of televised silhouette images in motion at Selfridge's Department Store in London. But if television is defined as the transmission of live, moving, half-tone (grayscale) images, and not silhouette, duotone, or still images, Baird first achieved this privately on October 2, 1925.[3] Then he gave the world's first public demonstration of a working television system to members of the Royal Institution and a newspaper reporter on January 26, 1926 at his laboratory in London. Unlike later electronic systems with several hundred lines of resolution, Baird's vertically scanned image, using a scanning disk embedded with a double spiral of lenses, had only 30 lines, just enough to reproduce a recognizable human face.
In 1927 Baird transmitted a signal over 438 miles of telephone line between London and Glasgow. In 1928 Baird's company (Baird Television Development Company / Cinema Television) broadcast the first transatlantic television signal, between London and New York, and the first shore-to-ship transmission. He also demonstrated an electromechanical color, infrared (dubbed "Noctovision"), and stereoscopic television, using additional lenses, disks and filters. In parallel he developed a video disk recording system dubbed "Phonovision"; a number of the Phonovision [1] recordings, dating back to 1927, still exist. In 1929 he became involved in the first experimental electromechanical television service in Germany. In 1931 he made the first live transmission, of the Epsom Derby. In 1932 he demonstrated ultra-short wave television. Baird's electromechanical system reached a peak of 240 lines of resolution on BBC television broadcasts in 1936, before being discontinued in favor of a 405-line all-electronic system developed by Marconi-EMI.
In the U.S., Charles Francis Jenkins was able to demonstrate on June 13, 1925, the transmission of the silhouette image of a toy windmill in motion from a naval radio station to his laboratory in Washington, using a lensed disk scanner with 48 lines per picture, 16 pictures per second. AT&T's Bell Telephone Laboratories transmitted half-tone images of transparencies in May 1925.
However, Herbert E. Ives of Bell Labs gave the most dramatic demonstration of television yet on April 7, 1927, when he field tested reflected-light television systems using small-scale (2 by 2.5 inches) and large-scale (24 by 30 inches) viewing screens over a wire link from Washington to New York City, and over-the-air broadcast from Whippany, New Jersey. The subjects, who included Secretary of Commerce Herbert Hoover, were illuminated by a flying-spot scanner beam that was scanned by a 50-aperture disk at 16 pictures per second.
The decisive solution — television operating on the basis of continuous electron emission with accumulation and storage of released secondary electrons during the entire scansion cycle — was first described by the Hungarian inventor Kálmán Tihanyi in 1926, with further refined versions in 1928.
On September 7, 1927, Philo Farnsworth's Image Dissector camera tube transmitted its first image, a simple straight line, at his laboratory at 202 Green Street in San Francisco. [2] By 1928, Farnsworth had developed the system sufficiently to hold a demonstration for the press, televising a motion picture film. In 1929, the system was further improved by elimination of a motor generator, so that his television system now had no mechanical moving parts. That year, Farnsworth transmitted the first live human images by his television system, including a three and a half-inch image of his wife Pem with her eyes closed (possibly due to the bright lighting required).
Farnsworth gave the world's first public demonstration of a complete all-electronic television system on 25 August 1934 at the Franklin Institute in Philadelphia. Other inventors had previously demonstrated components of such a system, or had shown an electronic system using still images or motion picture film. But Farnsworth was the first to coordinate both electronically scanned television cameras and electronically scanned television receivers, and present live, moving, half-tone (grayscale) images with them. Unfortunately, his cameras needed too much light, so his work came to a stop.
Vladimir Zworykin was also experimenting with the cathode ray tube to create and show images. In 1931 he and his team at RCA created their first successful electronic camera tube, dubbed the Iconoscope. Farnsworth believed it to interfere with the 1927 patent for his image dissector, and in a 1935 decision the U.S. Patent Office examiner agreed, finding prior art for Farnsworth against Zworykin. In November 1939, after losing in the courts, RCA gave Farnsworth a check for $1 million (USD) (the equivalent of $13.8 million (USD) in 2006) in order to license Farnsworth's patents.
In Britain Isaac Shoenburg used Zworykin's idea to develop Marconi-EMI's own Emitron tube, which formed the heart of the cameras they designed for the BBC. Using this, on November 2, 1936 a 405 line service was started from studios at Alexandra Palace, and transmitted from a specially-built mast atop one of the Victorian building's towers; it alternated for a short time with Baird's mechanical system in adjoining studios, but was more reliable and visibly superior. So began the world's first high-definition regular service. The mast is still in use today.
Most television researchers appreciated the value of color image transmission, with an early patent application in Russia in 1889 for a mechanically-scanned color system showing how early the importance of color was realized. John Logie Baird demonstrated the world's first color transmission on July 3, 1928, using scanning discs at the transmitting and receiving ends with three spirals of apertures, each spiral with filters of a different primary color; and three light sources at the receiving end, with a commutator to alternate their illumination. In 1938 shadow mask technology for color television was patented by Werner Flechsig in Germany.
Color television was demonstrated at the International radio exhibition Berlin in 1939. On August 16, 1944, Baird gave a demonstration of a fully electronic color television display. His 600-line color system used triple interlacing, using six scans to build each picture.[5]
In the electronically scanned era, the first color television demonstration was on February 5, 1940, when RCA privately showed to members of the FCC at the RCA plant in Camden, New Jersey, a television receiver producing color images by optically combining the images from two picture tubes onto a single rear-projection screen.[6] CBS began experimental color field tests using film as early as August 28, 1940, and live cameras by November 12.[7] The CBS "field sequential" color system was partly mechanical, with a disc made of red, blue, and green filters spinning inside the television camera at 1,200 rpm, and a similar disc spinning in synchronization in front of the cathode ray tube inside the receiver set.[8] RCA's later "dot sequential" color system had no moving parts, using a series of dichroic mirrors to separate and direct red, green, and blue light from the subject through three separate lenses into three scanning tubes, and electronic switching that allowed the tubes to send their signals in rotation, dot by dot. These signals were sorted by a second switching device in the receiver set and sent to red, green, and blue picture tubes, and combined by a second set of dichroic mirrors into a full color image.
NBC (owned by RCA) made its first field test of color television on February 20, 1941. CBS began daily color field tests on June 1, 1941.[9] These color systems were not compatible with existing black and white television sets, and as no color television sets were available to the public at this time, viewership of the color field tests was limited to RCA and CBS engineers and the invited press. The War Production Board halted the manufacture of television and radio equipment for civilian use from April 22, 1942 to August 20, 1945, limiting any opportunity to introduce color television to the general public.[10]
The post-war development of color television was dominated by three systems competing for approval by the FCC as the U.S. color broadcasting standard: CBS's field sequential system, which was incompatible with existing black and white sets without an adapter; RCA's dot sequential system, which in 1949 became compatible with existing black and white sets; and CTI's system (also incompatible with existing black and white sets), which used three camera lenses, behind which were color filters that produced red, green, and blue images side by side on a single scanning tube, and a receiver set that used lenses in front of the picture tube (which had sectors treated with different phosphorescent compounds to glow in red, green, or blue) to project these three side by side images into one combined picture on the viewing screen.[11]
During its campaign for FCC approval, CBS gave the world's first demonstrations of color television to the general public, showing an hour of color programs daily Mondays through Saturdays, beginning January 12, 1950, and running for the remainder of the month, over WOIC in Washington, D.C., where they could be viewed on eight 16-inch color receivers in a public building.[12] Due to high public demand, the broadcasts were resumed February 13–21, with several evening programs added.[13] CBS initiated a limited schedule of color broadcasts from its New York station WCBS-TV Mondays to Saturdays beginning November 14, 1950, making ten color receivers available for the viewing public.[14] All were broadcast using the single color camera that CBS owned.[15] The New York broadcasts were extended by coaxial cable to Philadelphia's WCAU-TV beginning December 13.[16]
After a series of hearings beginning in September 1949, the FCC found the RCA and CTI systems fraught with technical problems, inaccurate color reproduction, and expensive equipment, and so formally approved the CBS system as the U.S. color broadcasting standard on October 11 1950. An unsuccessful lawsuit by RCA delayed the world's first network color broadcast until June 25 1951, when a musical variety special titled simply Premiere was shown over a network of five east coast CBS affiliates.[17] Viewership was again extremely limited: the program could not be seen on black and white sets, and Variety estimated that only thirty prototype color receivers were available in the New York area. Regular color broadcasts began that same week with the daytime series The World Is Yours and Modern Homemakers.
While the CBS color broadcasting schedule gradually expanded to twelve hours per week (but never into prime time), and the color network expanded to eleven affiliates as far west as Chicago, its commercial success was doomed by the lack of color receivers necessary to watch the programs, the refusal of television manufacturers to create adapter mechanisms for their existing black and white sets,[18] and the unwillingness of advertisers to sponsor broadcasts seen by almost no one. CBS had bought a television manufacturer in April,[19] and in September 1951, production began on the first and only CBS-Columbia color television model.[20] But it was too little, too late. Only 200 sets had been shipped, and only 100 sold, when CBS pulled the plug on its color television system on October 20, 1951, and bought back all the CBS color sets it could to prevent lawsuits by disappointed customers.[21]
Starting before CBS color even got on the air, the U.S. television industry, represented by the National Television System Committee, worked in 1950–1953 to develop a color system that was compatible with existing black and white sets and would pass FCC quality standards, with RCA developing the hardware elements. When CBS testified before Congress in March 1953 that it had no further plans for its own color system,[22] the path was open for the NTSC to submit its petition for FCC approval in July 1953, which was granted on December 17.[23] The first publicly announced experimental TV broadcast of a program using the NTSC "compatible color" system was an episode of NBC's Kukla, Fran and Ollie on August 30, 1953.[24]
NBC made the first coast-to-coast color broadcast when it covered the Tournament of Roses Parade on January 1 1954, with public demonstrations given across the United States on prototype color receivers by manufacturers RCA, General Electric, Philco, Raytheon, Hallicrafters, Hoffman, Pacific Mercury and others.[25] A color model from Westinghouse ($1,295, or $9,400 in 2006 dollars) became available in the New York area on February 28 and is generally agreed to be the first production receiver using NTSC color offered to the public;[26] a less expensive color model from RCA reached dealers in April.[27] Television's first prime time network color series was The Marriage, a situation comedy broadcast live by NBC in the summer of 1954.[28] NBC's anthology series Ford Theatre became the first color filmed series that October.
NBC was naturally at the forefront of color programming because its parent company RCA manufactured the most successful line of color sets in the 1950s, and by 1959 RCA was the only remaining major manufacturer of color sets.[29] CBS and ABC, which were not affiliated with set manufacturers, and were not eager to promote their competitor's product, dragged their feet into color.[30] CBS ceased all regular color programming between 1960 and 1965, while ABC delayed its first color series until 1962.[31] The DuMont network, although it did have a television-manufacturing parent company, was in financial decline by 1954 and was dissolved two years later.[32] Thus the relatively small amount of network color programming, combined with the high cost of color television sets, meant that as late as 1964 only 3.1 percent of television households in the U.S. had a color set. NBC provided the catalyst for rapid color expansion by announcing that its prime time schedule for fall 1965 would be almost entirely in color (the exception being I Dream of Jeannie). All three broadcast networks were airing full color prime time schedules by the 1966–67 broadcast season.[33] But the number of color television sets sold in the U.S. did not exceed black and white sales until 1972, which was also the first year that more than fifty percent of television households in the U.S. had a color set.[34] This was also the year that "in color" notices before color television programs ended, due to the rise in color television set sales.
On August 31, 1946 González Camarena sent his first color transmission from his lab in the offices of The Mexican League of Radio Experiments at Lucerna St. #1, in Mexico City. The video signal was transmitted at a frequency of 115 MHz. and the audio in the 40 metre band. He obtained authorization to make the first publicly announced color broadcast in Mexico, on February 8, 1963, of the program ParaÃso Infantil on Mexico City's XHGC-TV.
As a consequence, although work on various color encoding systems started already in the 1950s, with the first SECAM patent being registered in 1956, many years had passed when the first broadcasts actually started in 1967. Unsatisfied with the performance of NTSC and of initial SECAM implementations, the Germans unveiled PAL (phase alternating line) in 1963, technically similar to NTSC but borrowing some ideas from SECAM. The French continued with SECAM, notably involving Russians in the development.
The first full-specification PAL receivers ("PAL-D") relied on a precision ultrasonic glass delay line, which in the early days was estimated would make up about a third of the cost of the receiver. Other color encoding systems had been already been proposed which would overcome the tint problems of NTSC using such a delay line, but PAL was unique in that an economy receiver (known as "PAL-S" for "simple PAL") could also be built without using a delay line, with a performance no worse than, and in most cases better than an equivalent NTSC model.
SECAM did not require such precision for its delay line, and could use much cheaper magnetostrictive metal types. Ironically, by the time PAL broadcasts commenced in 1967, advances in glassmaking techniques had dropped the cost of precision PAL delay lines so much that hardly any simple-PAL receivers were built commercially, and virtually all SECAM receivers used the same type of delay line as PAL receivers. By the end of the 20th century, glass delay lines had been completely replaced by all-electronic equivalents, and virtually all TV sets made now can decode PAL, NTSC and SECAM.
The first regular color broadcasts in Europe were by BBC2 beginning on July 1, 1967 (PAL). West Germany's first broadcast occurred in August (PAL), followed by the French in October (SECAM).
The PAL system spread through most of Western Europe and on into the territories of the old British, Portuguese, Belgian, Dutch, Austro-Hungarian, Ottoman and Chinese Empires.
In Italy there were debates to adopt a national color television system, the ISA, developed by Indesit, but that idea was scrapped. As a result, Italy was one of the last European countries to officially adopt the PAL system in 1977, after long technical experimentation. [35]
France, Luxembourg, and the Soviet Union along with their overseas territories opted for SECAM. SECAM was a popular choice in countries with a lot of hilly terrain, and technologically backward countries with a very large installed base of monochrome equipment, since the greater ruggedness of the SECAM signal could cope much better with poorly maintained equipment.
The only real drawback of SECAM is that, unlike PAL or NTSC, post-production of an encoded SECAM is not really possible without a severe drop in quality.
The first regular color broadcasts in SECAM were started on October 1, 1967, on France's Second Channel (ORTF 2e chaîne). In France and the UK color broadcasts were made on UHF frequencies, the VHF being band used for legacy black and white, 405 lines in UK or 819 lines in France, till the beginning of the eighties. Countries elsewhere that were already broadcasting 625-line monochrome on VHF and UHF, simply transmitted color programs on the same channels.
It should be noted that some British television programmes, particularly those made by or for ITC Entertainment, were shot on color film before the introduction of color television to the UK, for the purpose of sales to US networks. The first British show to be made in color was the drama series The Adventures of Sir Lancelot (1956-57), which was initially made in black and white but later shot in color for sale to the NBC network in the United States.
Hugo Gernsback's New York City radio station WRNY began a regular, if limited, schedule of live television broadcasts on August 14, 1928, using 48-line images. Simultaneously, Gernsback published Television, the world's first magazine about the medium.
General Electric's experimental station in Schenectady, New York, on the air sporadically since January 13, 1928, was able to broadcast reflected-light, 48-line images via shortwave as far as Los Angeles, and by September was making four television broadcasts weekly.
CBS's New York City station W2XAB began broadcasting the first regular seven days a week television schedule on July 21, 1931, with a 60-line electromechanical system. The first broadcast included Mayor Jimmy Walker, the Boswell Sisters, Kate Smith, and George Gershwin. The service ended in February 1933. Don Lee Broadcasting's station W6XAO in Los Angeles went on the air in December 1931. Using the UHF spectrum, it broadcast a regular schedule of filmed images every day except Sundays and holidays for several years.
By 1935, low-definition electromechanical television broadcasting had ceased in the United States except for a handful of stations run by public universities that continued to 1939. The Federal Communications Commission saw television in the continual flux of development with no consistent technical standards, hence all such stations in the U.S. were granted only experimental and not commercial licenses, hampering television's economic development. Just as importantly, Philo Farnsworth's August 1934 demonstration of an all-electronic system at the Franklin Institute in Philadelphia pointed out the direction of television's future.
On June 15, 1936, Don Lee Broadcasting began a month-long demonstration of high definition (240+ line) television in Los Angeles on W6XAO (later KTSL) with a 300-line image from motion picture film. By October, W6XAO was making daily television broadcasts of films. RCA demonstrated in New York City a 343-line electronic television broadcast, with live and film segments, to its licensees on July 7, 1936, and made its first public demonstration to the press on November 6. NBC began regularly scheduled broadcasts in New York on April 30, 1939 with a broadcast of the opening of the 1939 New York World's Fair. By June 1939, regularly scheduled 441-line electronic television broadcasts were available in New York City and Los Angeles, and by November on General Electric's station in Schenectady. From May through December 1939, the New York City NBC station (W2XBS) of General Electric broadcast twenty to fifty-eight hours of programming per month, Wednesday through Sunday of each week. The programming was 33% news, 29% drama, and 17% educational programming, with an estimated 2,000 receiving sets by the end of the year, and an estimated audience of five to eight thousand. A remote truck could cover outdoor events from up to 10 miles away from the transmitter, which was located atop the Empire State Building. Coaxial cable was used to cover events at Madison Square Garden. The coverage area for reliable reception was a radius of 40 to 50 miles from the Empire State Building, an area populated by more than 10,000,000 people (Lohr, 1940).
The FCC adopted NTSC television engineering standards on May 2, 1941, calling for 525 lines, 30 frames, with sound carried by frequency modulation. Sets sold since 1939 which were built for slightly lower resolution could still be adjusted to receive the new standard. (Dunlap, p31). The FCC saw television ready for commercial licensing, and the first such licenses were issued to NBC and CBS owned stations in New York on July 1, 1941, followed by Philco's station in Philadelphia. After the U.S. entry into World War II, the FCC reduced the required minimum air time for commercial television stations from 15 hours per week to 4 hours. Most TV stations suspended broadcasting. On the few that remained, programs included entertainment such as boxing and plays, events at Madison Square Garden, and illustrated war news as well as training for air raid wardens and first aid providers. In 1942, there were 5,000 sets in operation, but production of new TVs, radios, and other broadcasting equipment for civilian purposes was suspended from April 1942 to August 1945 (Dunlap).
The first official channel of French television appeared on February 13, 1935, date of the official inauguration of television in France which was broadcast in 60 lines from 8:15 to 8:30 pm. The program was of the actress Béatrice Bretty from the studio of Radio-PTT Vision at 103 rue de Grenelle in Paris. The broadcast had a range of 100 km (62 miles). On November 10, George Mandel, Minister of PTT, inaugurated the first broadcast in 180 lines from the transmitter of the Eiffel tower. On the 18th, Susy Wincker, first announcer since June, carried out a demonstration for the press from 5:30 to 7:30 pm. Broadcasts became regular from January 4, 1937 from 11:00 to 11:30 am and 8:00 to 8:30 pm during the week, and from 5:30 to 7:30 pm on Sundays. In July 1938, a decree defined for three years a standard of 455 lines VHF (whereas three standards are used for the experiments: 441 lines for Gramont, 450 lines for the Compagnie des Compteurs and 455 for Thomson). In 1939, there were about only 200 to 300 individual television sets, some of which were also available in a few public places.
With the entry of France into World War II the same year, broadcasts ceased and the transmitter of the Eiffel tower was sabotaged. On September 3, 1940, French television was seized by the German occupation forces. A technical agreement was signed by the Compagnie des Compteurs and Telefunken, and a financing agreement for the resuming of the service is signed by German Ministry of Post and Radiodiffusion Nationale (Vichy's radio). On May 7, 1943 at 3:00 evening broadcasts. The first broadcast of Fernsehsender Paris (Paris Télévision) was transmitted from rue Cognac-Jay. These regular broadcasts (5 1/4 hours a day) lasted until August 16, 1944. One thousand 441-line sets, most of which were installed in soldiers' hospitals, picked up the broadcasts.
In 1944, René Barthélemy developed an 819-line television standard. During the years of occupation, Barthélemy reached 1015 and even 1042 lines. On October 1, 1944, television service resumed after the liberation of Paris. The broadcasts were transmitted from the Cognacq-Jay studios. In October 1945, after repairs, the transmitter of the Eiffel Tower was back in service. On November 20, 1948, Mitterrand decreed a broadcast standard of 819 lines; broadcasting begins at the end of 1949 in this definition. France is the only European country to adopt it (others will choose 625 lines).
The first live broadcast from the European continent was made on 27 August 1950. The first live signal to Britain from the United States was broadcast via the Telstar satellite on 23 July 1962.
Programming is broadcast on television stations (sometimes called channels). At first, terrestrial broadcasting was the only way television could be distributed. Because bandwidth was limited, government regulation was normal.
In the U.S., the Federal Communications Commission in 1941 allowed stations to broadcast advertisements, but insisted on public service programming commitments as a requirement for a license. By contrast, the United Kingdom chose a different route, imposing a television licence fee on owners of television reception equipment, to fund the BBC, which had public service as part of its Royal Charter.
The development of cable and satellite means of distribution in the 1970s pushed businessmen to target channels towards a certain audience, and enabled the rise of subscription-based television channels, such as HBO and Sky.
The first commercially made electronic television sets with cathode ray tubes were manufactured by Telefunken in Germany in 1934, followed by other makers in Britain (1936) and America (1938). The cheapest of the pre-World War II factory-made American sets, a 1938 image-only model with a 3-inch (8 cm) screen, cost US$125, the equivalent of US$1,732 in 2005. The cheapest model with a 12-inch (30 cm) screen was $445 ($6,256).
An estimated 19,000 electronic television sets were manufactured in Britain, and about 1,600 in Germany, before World War II. About 7,000-8,000 electronic sets were made in the U.S. before the War Production Board halted manufacture in April 1942, production resuming in August 1945.
Television usage in the United States skyrocketed after World War II with the lifting of the manufacturing freeze, war-related technological advances, the gradual expansion of the television networks westward, the drop in set prices caused by mass production, increased leisure time, and additional disposable income. While only 0.5% of U.S. households had a television set in 1946, 55.7% had one in 1954, and 90% by 1962. In Britain, there were 15,000 television households in 1947, 1.4 million in 1952, and 15.1 million by 1968.
For many years different countries used different technical standards. France initially adopted the German 441-line standard but later upgraded to 819 lines, which gave the highest picture definition of any analogue TV system, approximately double the resolution of the British 405-line system. However this is not without a cost, in that the cameras need to produce four times the pixel rate (thus quadrupling the bandwidth), from pixels one-quarter the size, reducing the sensitivity by an equal amount. In practice the 819-line cameras never achieved anything like the resolution that could theoretically be transmitted by the 819 line system, and for color, France reverted to the same 625 lines as the European CCIR system.
Eventually the whole of Europe switched to the 625-line PAL standard, once more following Germany's example. Meanwhile in North America the original NTSC 525-line standard from 1941 was retained.
Mechanics (Greek Μηχανική
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The word television is a hybrid word, created from both Greek and Latin. Tele- is Greek for "far", while -vision is from the Latin visio, meaning "vision" or "sight". It is often abbreviated as TV or the telly.
Electromechanical television
The origins of what would become today's television system can be traced back to the discovery of the photoconductivity of the element selenium by Willoughby Smith in 1873, and the invention of a scanning disk by Paul Gottlieb Nipkow in 1884.
German student Nipkow proposed and patented the first electromechanical television system in 1884. Nipkow's spinning disk design is credited with being the first television image rasterizer. Constantin Perskyi had coined the word television in a paper read to the International Electricity Congress at the International World Fair in Paris on August 25, 1900. Perskyi's paper reviewed the existing electromechanical technologies, mentioning the work of Nipkow and others. The photoconductivity of selenium and Nipkow's scanning disk were first joined for practical use in the electronic transmission of still pictures and photographs, and by the first decade of the 20th century halftone photographs were being transmitted by facsimile over telegraph and telephone lines as a newspaper service.
However, it wasn't until 1907 that developments in amplification tube technology made the design practical.[1] The first demonstration of the instantaneous transmission of still duotone images was by Georges Rignoux and A. Fournier in Paris in 1909, using a rotating mirror-drum as the scanner, and a matrix of 64 selenium cells as the receiver.[2]
In 1911, Boris Rosing and his student Vladimir Kosma Zworykin created a television system that used a mechanical mirror-drum scanner to transmit, in Zworykin's words, "very crude images" over wires to the electronic Braun tube (cathode ray tube) in the receiver. Moving images were not possible because, in the scanner, "the sensitivity was not enough and the selenium cell was very laggy".
On March 25, 1925, Scottish inventor John Logie Baird gave a demonstration of televised silhouette images in motion at Selfridge's Department Store in London. But if television is defined as the transmission of live, moving, half-tone (grayscale) images, and not silhouette, duotone, or still images, Baird first achieved this privately on October 2, 1925.[3] Then he gave the world's first public demonstration of a working television system to members of the Royal Institution and a newspaper reporter on January 26, 1926 at his laboratory in London. Unlike later electronic systems with several hundred lines of resolution, Baird's vertically scanned image, using a scanning disk embedded with a double spiral of lenses, had only 30 lines, just enough to reproduce a recognizable human face.
In 1927 Baird transmitted a signal over 438 miles of telephone line between London and Glasgow. In 1928 Baird's company (Baird Television Development Company / Cinema Television) broadcast the first transatlantic television signal, between London and New York, and the first shore-to-ship transmission. He also demonstrated an electromechanical color, infrared (dubbed "Noctovision"), and stereoscopic television, using additional lenses, disks and filters. In parallel he developed a video disk recording system dubbed "Phonovision"; a number of the Phonovision [1] recordings, dating back to 1927, still exist. In 1929 he became involved in the first experimental electromechanical television service in Germany. In 1931 he made the first live transmission, of the Epsom Derby. In 1932 he demonstrated ultra-short wave television. Baird's electromechanical system reached a peak of 240 lines of resolution on BBC television broadcasts in 1936, before being discontinued in favor of a 405-line all-electronic system developed by Marconi-EMI.
In the U.S., Charles Francis Jenkins was able to demonstrate on June 13, 1925, the transmission of the silhouette image of a toy windmill in motion from a naval radio station to his laboratory in Washington, using a lensed disk scanner with 48 lines per picture, 16 pictures per second. AT&T's Bell Telephone Laboratories transmitted half-tone images of transparencies in May 1925.
However, Herbert E. Ives of Bell Labs gave the most dramatic demonstration of television yet on April 7, 1927, when he field tested reflected-light television systems using small-scale (2 by 2.5 inches) and large-scale (24 by 30 inches) viewing screens over a wire link from Washington to New York City, and over-the-air broadcast from Whippany, New Jersey. The subjects, who included Secretary of Commerce Herbert Hoover, were illuminated by a flying-spot scanner beam that was scanned by a 50-aperture disk at 16 pictures per second.
Electronic television
In 1911, engineer Alan Archibald Campbell-Swinton gave a speech in London, reported in The Times, describing in great detail how distant electric vision could be achieved by using cathode ray tubes at both the transmitting and receiving ends. The speech, which expanded on a letter he wrote to the journal Nature in 1908, was the first iteration of the electronic television method that is still used today. Others had already experimented with using a cathode ray tube as a receiver, but the concept of using one as a transmitter was novel.[4] By the late 1920s, when electromechanical television was still being introduced, inventors Philo Farnsworth and Vladimir Zworykin were already working separately on versions of all-electronic transmitting tubes.The decisive solution — television operating on the basis of continuous electron emission with accumulation and storage of released secondary electrons during the entire scansion cycle — was first described by the Hungarian inventor Kálmán Tihanyi in 1926, with further refined versions in 1928.
On September 7, 1927, Philo Farnsworth's Image Dissector camera tube transmitted its first image, a simple straight line, at his laboratory at 202 Green Street in San Francisco. [2] By 1928, Farnsworth had developed the system sufficiently to hold a demonstration for the press, televising a motion picture film. In 1929, the system was further improved by elimination of a motor generator, so that his television system now had no mechanical moving parts. That year, Farnsworth transmitted the first live human images by his television system, including a three and a half-inch image of his wife Pem with her eyes closed (possibly due to the bright lighting required).
Farnsworth gave the world's first public demonstration of a complete all-electronic television system on 25 August 1934 at the Franklin Institute in Philadelphia. Other inventors had previously demonstrated components of such a system, or had shown an electronic system using still images or motion picture film. But Farnsworth was the first to coordinate both electronically scanned television cameras and electronically scanned television receivers, and present live, moving, half-tone (grayscale) images with them. Unfortunately, his cameras needed too much light, so his work came to a stop.
Vladimir Zworykin was also experimenting with the cathode ray tube to create and show images. In 1931 he and his team at RCA created their first successful electronic camera tube, dubbed the Iconoscope. Farnsworth believed it to interfere with the 1927 patent for his image dissector, and in a 1935 decision the U.S. Patent Office examiner agreed, finding prior art for Farnsworth against Zworykin. In November 1939, after losing in the courts, RCA gave Farnsworth a check for $1 million (USD) (the equivalent of $13.8 million (USD) in 2006) in order to license Farnsworth's patents.
In Britain Isaac Shoenburg used Zworykin's idea to develop Marconi-EMI's own Emitron tube, which formed the heart of the cameras they designed for the BBC. Using this, on November 2, 1936 a 405 line service was started from studios at Alexandra Palace, and transmitted from a specially-built mast atop one of the Victorian building's towers; it alternated for a short time with Baird's mechanical system in adjoining studios, but was more reliable and visibly superior. So began the world's first high-definition regular service. The mast is still in use today.
Color television
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NBC title card, promoting their broadcast "in RCA color".
Color television in North America
United States
Color television in the United States had a protracted history due to conflicting technical systems vying for approval by the Federal Communications Commission for commercial use. Mechanically scanned color television was demonstrated by Bell Laboratories in June 1929 using three complete systems of photoelectric cells, amplifiers, glow-tubes, and color filters, with a series of mirrors to superimpose the red, green, and blue images into one full color image.In the electronically scanned era, the first color television demonstration was on February 5, 1940, when RCA privately showed to members of the FCC at the RCA plant in Camden, New Jersey, a television receiver producing color images by optically combining the images from two picture tubes onto a single rear-projection screen.[6] CBS began experimental color field tests using film as early as August 28, 1940, and live cameras by November 12.[7] The CBS "field sequential" color system was partly mechanical, with a disc made of red, blue, and green filters spinning inside the television camera at 1,200 rpm, and a similar disc spinning in synchronization in front of the cathode ray tube inside the receiver set.[8] RCA's later "dot sequential" color system had no moving parts, using a series of dichroic mirrors to separate and direct red, green, and blue light from the subject through three separate lenses into three scanning tubes, and electronic switching that allowed the tubes to send their signals in rotation, dot by dot. These signals were sorted by a second switching device in the receiver set and sent to red, green, and blue picture tubes, and combined by a second set of dichroic mirrors into a full color image.
NBC (owned by RCA) made its first field test of color television on February 20, 1941. CBS began daily color field tests on June 1, 1941.[9] These color systems were not compatible with existing black and white television sets, and as no color television sets were available to the public at this time, viewership of the color field tests was limited to RCA and CBS engineers and the invited press. The War Production Board halted the manufacture of television and radio equipment for civilian use from April 22, 1942 to August 20, 1945, limiting any opportunity to introduce color television to the general public.[10]
The post-war development of color television was dominated by three systems competing for approval by the FCC as the U.S. color broadcasting standard: CBS's field sequential system, which was incompatible with existing black and white sets without an adapter; RCA's dot sequential system, which in 1949 became compatible with existing black and white sets; and CTI's system (also incompatible with existing black and white sets), which used three camera lenses, behind which were color filters that produced red, green, and blue images side by side on a single scanning tube, and a receiver set that used lenses in front of the picture tube (which had sectors treated with different phosphorescent compounds to glow in red, green, or blue) to project these three side by side images into one combined picture on the viewing screen.[11]
During its campaign for FCC approval, CBS gave the world's first demonstrations of color television to the general public, showing an hour of color programs daily Mondays through Saturdays, beginning January 12, 1950, and running for the remainder of the month, over WOIC in Washington, D.C., where they could be viewed on eight 16-inch color receivers in a public building.[12] Due to high public demand, the broadcasts were resumed February 13–21, with several evening programs added.[13] CBS initiated a limited schedule of color broadcasts from its New York station WCBS-TV Mondays to Saturdays beginning November 14, 1950, making ten color receivers available for the viewing public.[14] All were broadcast using the single color camera that CBS owned.[15] The New York broadcasts were extended by coaxial cable to Philadelphia's WCAU-TV beginning December 13.[16]
After a series of hearings beginning in September 1949, the FCC found the RCA and CTI systems fraught with technical problems, inaccurate color reproduction, and expensive equipment, and so formally approved the CBS system as the U.S. color broadcasting standard on October 11 1950. An unsuccessful lawsuit by RCA delayed the world's first network color broadcast until June 25 1951, when a musical variety special titled simply Premiere was shown over a network of five east coast CBS affiliates.[17] Viewership was again extremely limited: the program could not be seen on black and white sets, and Variety estimated that only thirty prototype color receivers were available in the New York area. Regular color broadcasts began that same week with the daytime series The World Is Yours and Modern Homemakers.
While the CBS color broadcasting schedule gradually expanded to twelve hours per week (but never into prime time), and the color network expanded to eleven affiliates as far west as Chicago, its commercial success was doomed by the lack of color receivers necessary to watch the programs, the refusal of television manufacturers to create adapter mechanisms for their existing black and white sets,[18] and the unwillingness of advertisers to sponsor broadcasts seen by almost no one. CBS had bought a television manufacturer in April,[19] and in September 1951, production began on the first and only CBS-Columbia color television model.[20] But it was too little, too late. Only 200 sets had been shipped, and only 100 sold, when CBS pulled the plug on its color television system on October 20, 1951, and bought back all the CBS color sets it could to prevent lawsuits by disappointed customers.[21]
Starting before CBS color even got on the air, the U.S. television industry, represented by the National Television System Committee, worked in 1950–1953 to develop a color system that was compatible with existing black and white sets and would pass FCC quality standards, with RCA developing the hardware elements. When CBS testified before Congress in March 1953 that it had no further plans for its own color system,[22] the path was open for the NTSC to submit its petition for FCC approval in July 1953, which was granted on December 17.[23] The first publicly announced experimental TV broadcast of a program using the NTSC "compatible color" system was an episode of NBC's Kukla, Fran and Ollie on August 30, 1953.[24]
)
RCA CT-100 color set from 1954
NBC was naturally at the forefront of color programming because its parent company RCA manufactured the most successful line of color sets in the 1950s, and by 1959 RCA was the only remaining major manufacturer of color sets.[29] CBS and ABC, which were not affiliated with set manufacturers, and were not eager to promote their competitor's product, dragged their feet into color.[30] CBS ceased all regular color programming between 1960 and 1965, while ABC delayed its first color series until 1962.[31] The DuMont network, although it did have a television-manufacturing parent company, was in financial decline by 1954 and was dissolved two years later.[32] Thus the relatively small amount of network color programming, combined with the high cost of color television sets, meant that as late as 1964 only 3.1 percent of television households in the U.S. had a color set. NBC provided the catalyst for rapid color expansion by announcing that its prime time schedule for fall 1965 would be almost entirely in color (the exception being I Dream of Jeannie). All three broadcast networks were airing full color prime time schedules by the 1966–67 broadcast season.[33] But the number of color television sets sold in the U.S. did not exceed black and white sales until 1972, which was also the first year that more than fifty percent of television households in the U.S. had a color set.[34] This was also the year that "in color" notices before color television programs ended, due to the rise in color television set sales.
Cuba
Cuba in 1958 became the second country in the world to introduce color television broadcasting, with Havana's Channel 12 using the NTSC standard and RCA equipment. But the color transmissions ended when broadcasting stations were seized in the Cuban Revolution in 1959, and did not return until 1975, using equipment acquired from Japan's NEC Corporation, and SECAM equipment from the Soviet Union, adapted for the NTSC standard.Mexico
In Mexico, Guillermo González Camarena (1917–1965), invented an early color television transmission system. He received patents for color television systems in 1942 (U.S. Patent 2,296,019), 1960 and 1962. The 1942 patent (filed in Mexico on August 19, 1940) was for a synchronized color filter wheel adapter for monochrome television, similar to field sequential color receivers already demonstrated by John Logie Baird in England in 1939 and by CBS in the United States in August 1940.On August 31, 1946 González Camarena sent his first color transmission from his lab in the offices of The Mexican League of Radio Experiments at Lucerna St. #1, in Mexico City. The video signal was transmitted at a frequency of 115 MHz. and the audio in the 40 metre band. He obtained authorization to make the first publicly announced color broadcast in Mexico, on February 8, 1963, of the program ParaÃso Infantil on Mexico City's XHGC-TV.
Canada
Color television became available in Canada soon after regular color broadcasting began in the neighboring United States. Canadian stations began their own color broadcasts in 1966.European color television
European color television was developed somewhat later and was hindered by a continuing division on technical standards. Having decided to adopt a higher-definition 625-line system for monochrome transmissions, with a lower frame rate but with a higher overall bandwidth, Europeans could not directly adopt the U.S. color standard. This was widely perceived as inadequate anyway because of its hue error problems, which became particularly acute with the introduction of videotape recorders in the late 1950s. There was also less urgency, since there were fewer commercial motivations, European television broadcasters being predominantly state-owned at the time.As a consequence, although work on various color encoding systems started already in the 1950s, with the first SECAM patent being registered in 1956, many years had passed when the first broadcasts actually started in 1967. Unsatisfied with the performance of NTSC and of initial SECAM implementations, the Germans unveiled PAL (phase alternating line) in 1963, technically similar to NTSC but borrowing some ideas from SECAM. The French continued with SECAM, notably involving Russians in the development.
The first full-specification PAL receivers ("PAL-D") relied on a precision ultrasonic glass delay line, which in the early days was estimated would make up about a third of the cost of the receiver. Other color encoding systems had been already been proposed which would overcome the tint problems of NTSC using such a delay line, but PAL was unique in that an economy receiver (known as "PAL-S" for "simple PAL") could also be built without using a delay line, with a performance no worse than, and in most cases better than an equivalent NTSC model.
SECAM did not require such precision for its delay line, and could use much cheaper magnetostrictive metal types. Ironically, by the time PAL broadcasts commenced in 1967, advances in glassmaking techniques had dropped the cost of precision PAL delay lines so much that hardly any simple-PAL receivers were built commercially, and virtually all SECAM receivers used the same type of delay line as PAL receivers. By the end of the 20th century, glass delay lines had been completely replaced by all-electronic equivalents, and virtually all TV sets made now can decode PAL, NTSC and SECAM.
The first regular color broadcasts in Europe were by BBC2 beginning on July 1, 1967 (PAL). West Germany's first broadcast occurred in August (PAL), followed by the French in October (SECAM).
The PAL system spread through most of Western Europe and on into the territories of the old British, Portuguese, Belgian, Dutch, Austro-Hungarian, Ottoman and Chinese Empires.
In Italy there were debates to adopt a national color television system, the ISA, developed by Indesit, but that idea was scrapped. As a result, Italy was one of the last European countries to officially adopt the PAL system in 1977, after long technical experimentation. [35]
France, Luxembourg, and the Soviet Union along with their overseas territories opted for SECAM. SECAM was a popular choice in countries with a lot of hilly terrain, and technologically backward countries with a very large installed base of monochrome equipment, since the greater ruggedness of the SECAM signal could cope much better with poorly maintained equipment.
The only real drawback of SECAM is that, unlike PAL or NTSC, post-production of an encoded SECAM is not really possible without a severe drop in quality.
The first regular color broadcasts in SECAM were started on October 1, 1967, on France's Second Channel (ORTF 2e chaîne). In France and the UK color broadcasts were made on UHF frequencies, the VHF being band used for legacy black and white, 405 lines in UK or 819 lines in France, till the beginning of the eighties. Countries elsewhere that were already broadcasting 625-line monochrome on VHF and UHF, simply transmitted color programs on the same channels.
It should be noted that some British television programmes, particularly those made by or for ITC Entertainment, were shot on color film before the introduction of color television to the UK, for the purpose of sales to US networks. The first British show to be made in color was the drama series The Adventures of Sir Lancelot (1956-57), which was initially made in black and white but later shot in color for sale to the NBC network in the United States.
Asia Pacific color television
In Japan, NHK introduced color television, using a variation of the NTSC system (called NTSC-J), on September 10, 1960. However, other countries in the region did not follow suit until much later, and instead used the PAL system, such as Singapore (1973), New Zealand (1973) and Australia (1975), with India not introducing it until 1982. South Korea did not introduce color (using NTSC) until 1980, although it was already manufacturing color television sets for export.African color television
The first color television service in Africa was introduced on the Tanzanian island of Zanzibar, in 1973, using PAL. At the time, South Africa did not have a television service at all, owing to opposition from the apartheid regime, but in 1976, one was finally launched. Nigeria adopted PAL for color transmissions in the mid-1970s, but countries such as Ghana and Zimbabwe continued with black and white until the late 1980s.South American color television
In the early 1970s, Brazil became the first South American country to receive color TV, using a specially-modified version of PAL called PAL-M, combining both NTSC and PAL, in contrast to most other countries in the Americas, which had adopted NTSC. Its first transmission was February 19, 1972.Broadcast television
For individual countries, see Timeline of the introduction of television in countries.United States and Canada
Below is a list showing when USA states and Canadian provinces established their first commercially licensed television stations.)
Television aerial on a rooftop
United States
The first regularly scheduled television service in the United States began on July 2, 1928. The Federal Radio Commission authorized C.F. Jenkins to broadcast from experimental station W3XK in Wheaton, Maryland, a suburb of Washington, D.C. But for at least the first eighteen months, only silhouette images from motion picture film were broadcast.Hugo Gernsback's New York City radio station WRNY began a regular, if limited, schedule of live television broadcasts on August 14, 1928, using 48-line images. Simultaneously, Gernsback published Television, the world's first magazine about the medium.
General Electric's experimental station in Schenectady, New York, on the air sporadically since January 13, 1928, was able to broadcast reflected-light, 48-line images via shortwave as far as Los Angeles, and by September was making four television broadcasts weekly.
CBS's New York City station W2XAB began broadcasting the first regular seven days a week television schedule on July 21, 1931, with a 60-line electromechanical system. The first broadcast included Mayor Jimmy Walker, the Boswell Sisters, Kate Smith, and George Gershwin. The service ended in February 1933. Don Lee Broadcasting's station W6XAO in Los Angeles went on the air in December 1931. Using the UHF spectrum, it broadcast a regular schedule of filmed images every day except Sundays and holidays for several years.
By 1935, low-definition electromechanical television broadcasting had ceased in the United States except for a handful of stations run by public universities that continued to 1939. The Federal Communications Commission saw television in the continual flux of development with no consistent technical standards, hence all such stations in the U.S. were granted only experimental and not commercial licenses, hampering television's economic development. Just as importantly, Philo Farnsworth's August 1934 demonstration of an all-electronic system at the Franklin Institute in Philadelphia pointed out the direction of television's future.
On June 15, 1936, Don Lee Broadcasting began a month-long demonstration of high definition (240+ line) television in Los Angeles on W6XAO (later KTSL) with a 300-line image from motion picture film. By October, W6XAO was making daily television broadcasts of films. RCA demonstrated in New York City a 343-line electronic television broadcast, with live and film segments, to its licensees on July 7, 1936, and made its first public demonstration to the press on November 6. NBC began regularly scheduled broadcasts in New York on April 30, 1939 with a broadcast of the opening of the 1939 New York World's Fair. By June 1939, regularly scheduled 441-line electronic television broadcasts were available in New York City and Los Angeles, and by November on General Electric's station in Schenectady. From May through December 1939, the New York City NBC station (W2XBS) of General Electric broadcast twenty to fifty-eight hours of programming per month, Wednesday through Sunday of each week. The programming was 33% news, 29% drama, and 17% educational programming, with an estimated 2,000 receiving sets by the end of the year, and an estimated audience of five to eight thousand. A remote truck could cover outdoor events from up to 10 miles away from the transmitter, which was located atop the Empire State Building. Coaxial cable was used to cover events at Madison Square Garden. The coverage area for reliable reception was a radius of 40 to 50 miles from the Empire State Building, an area populated by more than 10,000,000 people (Lohr, 1940).
The FCC adopted NTSC television engineering standards on May 2, 1941, calling for 525 lines, 30 frames, with sound carried by frequency modulation. Sets sold since 1939 which were built for slightly lower resolution could still be adjusted to receive the new standard. (Dunlap, p31). The FCC saw television ready for commercial licensing, and the first such licenses were issued to NBC and CBS owned stations in New York on July 1, 1941, followed by Philco's station in Philadelphia. After the U.S. entry into World War II, the FCC reduced the required minimum air time for commercial television stations from 15 hours per week to 4 hours. Most TV stations suspended broadcasting. On the few that remained, programs included entertainment such as boxing and plays, events at Madison Square Garden, and illustrated war news as well as training for air raid wardens and first aid providers. In 1942, there were 5,000 sets in operation, but production of new TVs, radios, and other broadcasting equipment for civilian purposes was suspended from April 1942 to August 1945 (Dunlap).
Canada
The Canadian Broadcasting Corporation (CBC) adopted the American NTSC 525-line B/W 60 field per second system as its broadcast standard. It began television broadcasting in Canada in September 1952. The first broadcast was on September 6, 1952 from its Montreal, Quebec station CBFT. The premiere broadcast was bilingual, spoken in English and French. Two days later, on September 8, 1952, the Toronto, Ontario station CBLT went on the air. This became the English-speaking flagship station for the country. The CBC’s first privately owned affiliate television station, CKSO in Sudbury, Ontario, launched in October 1953 (at the time, all private stations were expected to affiliate with the CBC, a condition that was relaxed in 1960–61).France
On April 14, 1931, was the first transmission with a thirty-line standard by René Barthélemy. On December 6, 1931, Henri de France created the Compagnie Générale de Télévision (CGT). In December 1932, Bathélemy carried out an experimental program in black and white (definition: 60 lines) one hour per week, "Paris Télévision", which gradually became daily from early 1933.The first official channel of French television appeared on February 13, 1935, date of the official inauguration of television in France which was broadcast in 60 lines from 8:15 to 8:30 pm. The program was of the actress Béatrice Bretty from the studio of Radio-PTT Vision at 103 rue de Grenelle in Paris. The broadcast had a range of 100 km (62 miles). On November 10, George Mandel, Minister of PTT, inaugurated the first broadcast in 180 lines from the transmitter of the Eiffel tower. On the 18th, Susy Wincker, first announcer since June, carried out a demonstration for the press from 5:30 to 7:30 pm. Broadcasts became regular from January 4, 1937 from 11:00 to 11:30 am and 8:00 to 8:30 pm during the week, and from 5:30 to 7:30 pm on Sundays. In July 1938, a decree defined for three years a standard of 455 lines VHF (whereas three standards are used for the experiments: 441 lines for Gramont, 450 lines for the Compagnie des Compteurs and 455 for Thomson). In 1939, there were about only 200 to 300 individual television sets, some of which were also available in a few public places.
With the entry of France into World War II the same year, broadcasts ceased and the transmitter of the Eiffel tower was sabotaged. On September 3, 1940, French television was seized by the German occupation forces. A technical agreement was signed by the Compagnie des Compteurs and Telefunken, and a financing agreement for the resuming of the service is signed by German Ministry of Post and Radiodiffusion Nationale (Vichy's radio). On May 7, 1943 at 3:00 evening broadcasts. The first broadcast of Fernsehsender Paris (Paris Télévision) was transmitted from rue Cognac-Jay. These regular broadcasts (5 1/4 hours a day) lasted until August 16, 1944. One thousand 441-line sets, most of which were installed in soldiers' hospitals, picked up the broadcasts.
In 1944, René Barthélemy developed an 819-line television standard. During the years of occupation, Barthélemy reached 1015 and even 1042 lines. On October 1, 1944, television service resumed after the liberation of Paris. The broadcasts were transmitted from the Cognacq-Jay studios. In October 1945, after repairs, the transmitter of the Eiffel Tower was back in service. On November 20, 1948, Mitterrand decreed a broadcast standard of 819 lines; broadcasting begins at the end of 1949 in this definition. France is the only European country to adopt it (others will choose 625 lines).
Germany
Electromechanical broadcasts began in Germany in 1929, but were without sound until 1934. Network electronic service started on March 22, 1935, on 180 lines using telecine transmission of film, intermediate film system, or cameras using the Nipkow Disk. Transmissions using cameras based on the iconoscope began on January 15, 1936. The Berlin Summer Olympic Games were televised, using both fully electronic iconoscope-based cameras and intermediate film cameras, to Berlin and Hamburg in August 1936. Twenty-eight public television rooms were opened for anybody who did not own a television set. The Germans had a 441-line system on the air in February 1937, and during World War II brought it to France, where they broadcast off the Eiffel Tower. The American Armed Forces Radio Network at the end of World War II, wishing to provide US TV programming to the occupation forces in Germany, used US TV receivers made to operate at 525 lines and 60 fields. US broadcast equipment was modified; they changed the vertical frequency to 50 Hz to avoid power line wiggles, changed the horizontal frequency from 15,750 Hz to 15,625 Hz a 0.5 microsecond change in the length of a line. With this signal, US TV receivers with only an adjustment to the vertical hold control had a 625 line, 50 field scan, which became the German standard.Great Britain
The first British television broadcast was made by Baird Television's electromechanical system over the BBC radio transmitter in September 1929. Baird provided a limited amount of programming five days a week by 1930. On August 22, 1932, BBC launched its own regular service using Baird's 30-line electromechanical system, continuing until September 11, 1935. On November 2, 1936 the BBC began broadcasting a dual-system service, alternating between Marconi-EMI's 405-line standard and Baird's improved 240-line standard, from Alexandra Palace in London, making the BBC Television Service (now BBC One) the world's first regular high-definition television service. The government, on advice from a special advisory committee, decided that Marconi-EMI's electronic system gave the superior picture, and the Baird system was dropped in February 1937. TV broadcasts in London were on the air an average of four hours daily from 1936 to 1939. There were 12,000 to 15,000 receivers. Some sets in restaurants or bars might have 100 viewers for sport events (Dunlap, p56).The outbreak of the Second World War caused the BBC service to be suspended on September 1, 1939, resuming from Alexandra Palace on June 7, 1946.The first live broadcast from the European continent was made on 27 August 1950. The first live signal to Britain from the United States was broadcast via the Telstar satellite on 23 July 1962.
Soviet Union (USSR)
The Soviet Union began offering 30-line electromechanical test broadcasts in Moscow on October 31, 1931, and a commercially manufactured television set in 1932. The first experimental transmissions of electronic television took place in Moscow on March 9, 1937, using equipment manufactured and installed by RCA. Regular broadcasting began on December 31, 1938.Later development
The first regular television transmissions in Canada began in 1952 when the CBC put two stations on the air, one in Montreal, Quebec on September 6, and another in Toronto, Ontario two days later.Technological innovations
The first live transcontinental television broadcast took place in San Francisco, California from the Japanese Peace Treaty Conference on September 4, 1951. In 1958, the CBC completed the longest television network in the world, from Sydney, Nova Scotia to Victoria, British Columbia. Reportedly, the first continuous live broadcast of a breaking news story in the world was conducted by the CBC during the Springhill Mining Disaster which began on October 23 of that year.Programming is broadcast on television stations (sometimes called channels). At first, terrestrial broadcasting was the only way television could be distributed. Because bandwidth was limited, government regulation was normal.
In the U.S., the Federal Communications Commission in 1941 allowed stations to broadcast advertisements, but insisted on public service programming commitments as a requirement for a license. By contrast, the United Kingdom chose a different route, imposing a television licence fee on owners of television reception equipment, to fund the BBC, which had public service as part of its Royal Charter.
The development of cable and satellite means of distribution in the 1970s pushed businessmen to target channels towards a certain audience, and enabled the rise of subscription-based television channels, such as HBO and Sky.
Overview
Practically every country in the world now has developed at least one television channel. Television has grown up all over the world, enabling every country to share aspects of their culture and society with others.Television sets
In television's electromechanical era, commercially made television sets were sold from 1928 to 1934 in the United Kingdom, United States, and Russia. The earliest commercially made sets sold by Baird in the UK and the U.S. in 1928 were radios with the addition of a television device consisting of a neon tube behind a mechanically spinning disk (the Nipkow disk) with a spiral of apertures that produced a red postage-stamp size image, enlarged to twice that size by a magnifying glass. The Baird "Televisor" was also available without the radio. The Televisor sold in 1930-1933 is considered the first mass-produced set, selling about a thousand units.The first commercially made electronic television sets with cathode ray tubes were manufactured by Telefunken in Germany in 1934, followed by other makers in Britain (1936) and America (1938). The cheapest of the pre-World War II factory-made American sets, a 1938 image-only model with a 3-inch (8 cm) screen, cost US$125, the equivalent of US$1,732 in 2005. The cheapest model with a 12-inch (30 cm) screen was $445 ($6,256).
An estimated 19,000 electronic television sets were manufactured in Britain, and about 1,600 in Germany, before World War II. About 7,000-8,000 electronic sets were made in the U.S. before the War Production Board halted manufacture in April 1942, production resuming in August 1945.
Television usage in the United States skyrocketed after World War II with the lifting of the manufacturing freeze, war-related technological advances, the gradual expansion of the television networks westward, the drop in set prices caused by mass production, increased leisure time, and additional disposable income. While only 0.5% of U.S. households had a television set in 1946, 55.7% had one in 1954, and 90% by 1962. In Britain, there were 15,000 television households in 1947, 1.4 million in 1952, and 15.1 million by 1968.
For many years different countries used different technical standards. France initially adopted the German 441-line standard but later upgraded to 819 lines, which gave the highest picture definition of any analogue TV system, approximately double the resolution of the British 405-line system. However this is not without a cost, in that the cameras need to produce four times the pixel rate (thus quadrupling the bandwidth), from pixels one-quarter the size, reducing the sensitivity by an equal amount. In practice the 819-line cameras never achieved anything like the resolution that could theoretically be transmitted by the 819 line system, and for color, France reverted to the same 625 lines as the European CCIR system.
Eventually the whole of Europe switched to the 625-line PAL standard, once more following Germany's example. Meanwhile in North America the original NTSC 525-line standard from 1941 was retained.
Television inventors/pioneers
Important people in the development of TV technology in the 19th or 20th centuries.Television museums
- Early Television Museum
- Museum of Television and Radio
- Museum of Broadcast Communications
- National Media Museum
See also
- Golden Age of Television, c1949–1960 in the US
- History of radio
- Television
- Archive of American Television
- Dunlap, Orrin E. "The Future of Television". New York and London: Harper Brothers, 1942.
- Lohr, Lenox, "Television Broadcasting". New York: McGraw Hill, 1940.
- Video monitor timeline
- Oldest television station
- List of experimental television stations
- Timeline of the introduction of television in countries
- Timeline of the introduction of color television in countries
- Geographical usage of television
- NTSC
- PAL
- SECAM
References
1. ^ "Sending Photographs by Telegraph", New York Times, September 20, 1907, Sunday Magazine, p. 7.
2. ^ Henry de Varigny, "La vision à distance", L'Illustration, Paris, 11 December 1909, p. 451.
3. ^ Strictly speaking, Baird had not yet achieved moving images on October 2: his scanner worked at only five images per second, below the threshold required to give the illusion of motion, usually defined as at least 12 images per second. By January, he had improved the scan rate to 12.5 images per second.
4. ^ Albert Abrahamson, Zworykin, Pioneer of Television, p. 16
5. ^ Albert Abramson, The History of Television, 1942 to 2000, McFarland & Company, 2003, pp. 13-14. ISBN 0786412208
6. ^ Kenyon Kilbon, Pioneering in Electronics: A Short History of the Origins and Growth of RCA Laboratories, Radio Corporation of America, 1919 to 1964, Chapter Nine — Television: Monochrome to Color, 1964. V.K. Zworykin with Frederick Olessi, Iconoscope: An Autobiography of Vladimir Zworykin, Chapter 10 — Television Becomes a Reality, 1945-1954, 1971. "The system used two color filters in combination with photocells and a flying spot scanner for pickup." Alfred V. Roman, The Historical Development of Color Television Systems, doctoral dissertation, New York University, 1967, p. 49.
7. ^ "Color Television Success in Test," New York Times, Aug. 30, 1940, p. 21. "CBS Demonstrates Full Color Television," Wall Street Journal, Sept. 5, 1940, p. 1. "Television Hearing Set," New York Times, Nov. 13, 1940, p. 26.
8. ^ Peter C. Goldmark, assignor to Columbia Broadcasting System, "Color Television", U.S. Patent 2,480,571, filed Sept. 7, 1940.
9. ^ Ed Reitan, RCA-NBC Color Firsts in Television (commented).
10. ^ "Making of Radios and Phonographs to End April 22," New York Times, March 8, 1942, p. 1. "Radio Production Curbs Cover All Combinations," Wall Street Journal, June 3, 1942, p. 4. "WPB Cancels 210 Controls; Radios, Trucks in Full Output," New York Times, August 21, 1945, p. 1.
11. ^ "TV Color Controversy," Life, February 27, 1950.
12. ^ "Washington Chosen for First Color Showing; From Ages 4 to 90, Audience Amazed", The Washington Post, Jan. 13, 1950, p. B2.
13. ^ "Color TV Tests To Be Resumed In Washington", The Washington Post, February 12, 1950, p. M5.
14. ^ "CBS Color Television To Make Public Debut In N.Y. Next Week", The Wall Street Journal, November 9, 1950, p. 18.
15. ^ "You Can See The Blood on Color Video," The Washington Post, Jan. 15, 1950, p. L1. "Video Color Test Begins on C.B.S.," New York Times, Nov. 14, 1950, p. 44.
16. ^ "CBS Color Preview Seen By 2,000 in Philadelphia", The Wall Street Journal, December 16, 1950, p. 10.
17. ^ "C.B.S. Color Video Presents a 'First'," New York Times, June 26, 1951, p. 31.
18. ^ "CBS Color System Makes Television Set Makers See Red", Wall Street Journal, October 17, 1950, p. 1. Two exceptions among the major television manufacturers were Westinghouse and Admiral, which offered color adapter-converters to receive color broadcasts in black and white. "Westinghouse to Sell Adapter for CBS Color TV Signals", Wall Street Journal, August 7, 1951, p. 18.
19. ^ "Hytron's Deal With CBS Seen TV Color Aid", The Washington Post, April 12, 1951, p. 15.
20. ^ "CBS Subsidiary Starts Mass Production of Color Television Sets," Wall Street Journal, Sep 13, 1951, p. 18.
21. ^ "Color TV Shelved As a Defense Step," New York Times, Oct 20, 1951, p. 1. "Action of Defense Mobilizer in Postponing Color TV Poses Many Question for the Industry," New York Times, Oct. 22, 1951, p. 23. Ed Reitan, CBS Field Sequential Color System, 1997.
22. ^ "CBS Says Confusion Now Bars Color TV," Washington Post, March 26, 1953, p. 39.
23. ^ "F.C.C. Rules Color TV Can Go on Air at Once," New York Times, Dec. 19, 1953, p. 1.
24. ^ "NBC Launches First Publicly-Announced Color Television Show," Wall Street Journal, Aug 31, 1953, p. 4.
25. ^ "Television in Review: N.B.C. Color," New York Times, Jan. 4, 1954, p. 28. Two days earlier Admiral demonstrated to their distributors the prototype of Admiral's first color television set planned for consumer sale using the NTSC standards, priced at $1,175 ($8,600 in 2006 dollars). It is not known when the later commercial version of this receiver was first sold. Production was extremely limited, and no advertisements for it were published in New York or Washington newspapers. "First Admiral Color TV," New York Times, Dec 31, 1953, p. 22. "Admiral's First Color TV Set," Wall Street Journal, Dec. 31, 1953, p. 5.
26. ^ Westinghouse display ad, New York Times, Feb. 28, 1954, p. 57. Only 30 sets were sold in its first month. "Color TV Reduced by Westinghouse," April 2, 1954, p. 36.
27. ^ RCA's manufacture of color sets started March 25, 1954, and 5,000 Model CT-100's were produced. Initially $1,000, its price was cut to $495 in August 1954. "R.C.A. Halves Cost of Color TV Sets," New York Times, Aug. 10, 1954, p. 21.
28. ^ "News of TV and Radio," New York Times, June 20, 1954, p. X11.
29. ^ RCA made about 95 percent of the color television sets sold in the U.S. in 1960. Peter Bart, "Advertising: Color TV Set Output Spurred," New York Times, July 31, 1961, p. 27.
30. ^ "Chasing the Rainbow," Time, June 30, 1958.
31. ^ The Flintstones, The Jetsons, and Beany and Cecil. "A.B.C.-TV To Start Color Programs," New York Times, April 1, 1962, p. 84. "More Color," New York Times, Sept. 23, 1962, p. 145. Ed Reitan, RCA-NBC Firsts in Television. Jack Gould, "Tinted TV Shows Its Colors," New York Times, Nov. 29, 1964, p. X17.
32. ^ Clarke Ingram, The DuMont Television Network, Chapter Seven: Finale.
33. ^ While at least one show, CBS' The Lucy Show, did not broadcast its episodes in color until the start of the 1965-66 broadcast season, that show's producers began filming in color in 1963, with the thought that they would command more money when sold into syndication.
34. ^ Television Facts and Statistics — 1939 to 2000, Television History — The First 75 Years.
35. ^ The adoption of color television in Italy (Italian).
2. ^ Henry de Varigny, "La vision à distance", L'Illustration, Paris, 11 December 1909, p. 451.
3. ^ Strictly speaking, Baird had not yet achieved moving images on October 2: his scanner worked at only five images per second, below the threshold required to give the illusion of motion, usually defined as at least 12 images per second. By January, he had improved the scan rate to 12.5 images per second.
4. ^ Albert Abrahamson, Zworykin, Pioneer of Television, p. 16
5. ^ Albert Abramson, The History of Television, 1942 to 2000, McFarland & Company, 2003, pp. 13-14. ISBN 0786412208
6. ^ Kenyon Kilbon, Pioneering in Electronics: A Short History of the Origins and Growth of RCA Laboratories, Radio Corporation of America, 1919 to 1964, Chapter Nine — Television: Monochrome to Color, 1964. V.K. Zworykin with Frederick Olessi, Iconoscope: An Autobiography of Vladimir Zworykin, Chapter 10 — Television Becomes a Reality, 1945-1954, 1971. "The system used two color filters in combination with photocells and a flying spot scanner for pickup." Alfred V. Roman, The Historical Development of Color Television Systems, doctoral dissertation, New York University, 1967, p. 49.
7. ^ "Color Television Success in Test," New York Times, Aug. 30, 1940, p. 21. "CBS Demonstrates Full Color Television," Wall Street Journal, Sept. 5, 1940, p. 1. "Television Hearing Set," New York Times, Nov. 13, 1940, p. 26.
8. ^ Peter C. Goldmark, assignor to Columbia Broadcasting System, "Color Television", U.S. Patent 2,480,571, filed Sept. 7, 1940.
9. ^ Ed Reitan, RCA-NBC Color Firsts in Television (commented).
10. ^ "Making of Radios and Phonographs to End April 22," New York Times, March 8, 1942, p. 1. "Radio Production Curbs Cover All Combinations," Wall Street Journal, June 3, 1942, p. 4. "WPB Cancels 210 Controls; Radios, Trucks in Full Output," New York Times, August 21, 1945, p. 1.
11. ^ "TV Color Controversy," Life, February 27, 1950.
12. ^ "Washington Chosen for First Color Showing; From Ages 4 to 90, Audience Amazed", The Washington Post, Jan. 13, 1950, p. B2.
13. ^ "Color TV Tests To Be Resumed In Washington", The Washington Post, February 12, 1950, p. M5.
14. ^ "CBS Color Television To Make Public Debut In N.Y. Next Week", The Wall Street Journal, November 9, 1950, p. 18.
15. ^ "You Can See The Blood on Color Video," The Washington Post, Jan. 15, 1950, p. L1. "Video Color Test Begins on C.B.S.," New York Times, Nov. 14, 1950, p. 44.
16. ^ "CBS Color Preview Seen By 2,000 in Philadelphia", The Wall Street Journal, December 16, 1950, p. 10.
17. ^ "C.B.S. Color Video Presents a 'First'," New York Times, June 26, 1951, p. 31.
18. ^ "CBS Color System Makes Television Set Makers See Red", Wall Street Journal, October 17, 1950, p. 1. Two exceptions among the major television manufacturers were Westinghouse and Admiral, which offered color adapter-converters to receive color broadcasts in black and white. "Westinghouse to Sell Adapter for CBS Color TV Signals", Wall Street Journal, August 7, 1951, p. 18.
19. ^ "Hytron's Deal With CBS Seen TV Color Aid", The Washington Post, April 12, 1951, p. 15.
20. ^ "CBS Subsidiary Starts Mass Production of Color Television Sets," Wall Street Journal, Sep 13, 1951, p. 18.
21. ^ "Color TV Shelved As a Defense Step," New York Times, Oct 20, 1951, p. 1. "Action of Defense Mobilizer in Postponing Color TV Poses Many Question for the Industry," New York Times, Oct. 22, 1951, p. 23. Ed Reitan, CBS Field Sequential Color System, 1997.
22. ^ "CBS Says Confusion Now Bars Color TV," Washington Post, March 26, 1953, p. 39.
23. ^ "F.C.C. Rules Color TV Can Go on Air at Once," New York Times, Dec. 19, 1953, p. 1.
24. ^ "NBC Launches First Publicly-Announced Color Television Show," Wall Street Journal, Aug 31, 1953, p. 4.
25. ^ "Television in Review: N.B.C. Color," New York Times, Jan. 4, 1954, p. 28. Two days earlier Admiral demonstrated to their distributors the prototype of Admiral's first color television set planned for consumer sale using the NTSC standards, priced at $1,175 ($8,600 in 2006 dollars). It is not known when the later commercial version of this receiver was first sold. Production was extremely limited, and no advertisements for it were published in New York or Washington newspapers. "First Admiral Color TV," New York Times, Dec 31, 1953, p. 22. "Admiral's First Color TV Set," Wall Street Journal, Dec. 31, 1953, p. 5.
26. ^ Westinghouse display ad, New York Times, Feb. 28, 1954, p. 57. Only 30 sets were sold in its first month. "Color TV Reduced by Westinghouse," April 2, 1954, p. 36.
27. ^ RCA's manufacture of color sets started March 25, 1954, and 5,000 Model CT-100's were produced. Initially $1,000, its price was cut to $495 in August 1954. "R.C.A. Halves Cost of Color TV Sets," New York Times, Aug. 10, 1954, p. 21.
28. ^ "News of TV and Radio," New York Times, June 20, 1954, p. X11.
29. ^ RCA made about 95 percent of the color television sets sold in the U.S. in 1960. Peter Bart, "Advertising: Color TV Set Output Spurred," New York Times, July 31, 1961, p. 27.
30. ^ "Chasing the Rainbow," Time, June 30, 1958.
31. ^ The Flintstones, The Jetsons, and Beany and Cecil. "A.B.C.-TV To Start Color Programs," New York Times, April 1, 1962, p. 84. "More Color," New York Times, Sept. 23, 1962, p. 145. Ed Reitan, RCA-NBC Firsts in Television. Jack Gould, "Tinted TV Shows Its Colors," New York Times, Nov. 29, 1964, p. X17.
32. ^ Clarke Ingram, The DuMont Television Network, Chapter Seven: Finale.
33. ^ While at least one show, CBS' The Lucy Show, did not broadcast its episodes in color until the start of the 1965-66 broadcast season, that show's producers began filming in color in 1963, with the thought that they would command more money when sold into syndication.
34. ^ Television Facts and Statistics — 1939 to 2000, Television History — The First 75 Years.
35. ^ The adoption of color television in Italy (Italian).
Further reading
- Abramson, Albert. The History of Television, 1880 to 1941. (1987). Jefferson, NC: McFarland & Co. ISBN 0-89950-284-9.
- Abramson, Albert. The History of Television, 1942 to 2000. (2003). Jefferson, NC: McFarland & Co. ISBN 0-78641-220-8.
- Burns, R. W. Television: An international history of the formative years. (1998). IEE History of Technology Series, 22. London: IEE. ISBN 0-85296-914-7.
- Fisher, David E. and Marshall Jon Fisher. Tube: the Invention of Television. (1996). Washington: Counterpoint. ISBN 1887178171.
- Shiers, George. Early Television: A Bibliographic Guide to 1940. (1997). Garland Reference Library of Social Science. ISBN 0-82407-782-2.
External links
Links related to the development or history of television- Television history — inventors including a timeline
- Who Invented Television - Reconciling The Historical Origins of Electronic Video
- Photos of early TV receivers
- Article describing development of the television
- Early television museum (extensive online presence)
- Ed Reitan's Color Television History
- Detailed timeline of communications media (including the TV)
- The history of Australian television
- Video Active: Creating Access to Television History
- A Visit to Our Studios: a television program exploring the studios at Johns Hopkins University in 1951
- Archive of American Television (information and links to videotaped oral history interviews with TV legends and pioneers)
| [ edit ] Video formats |
|---|
| Analog broadcast |
| 525 lines: NTSC | NTSC-J | PAL-M |
| 625 lines: PAL | PAL-N | PALplus | SECAM |
| Defunct systems: Pre-1940 | 405 lines | 819 lines | Baird-Nipkow | MAC | MUSE |
| Multichannel audio: BTSC (MTS) | NICAM-728 | Zweiton (A2, IGR) |
| Hidden signals: Captioning | Teletext | CGMS-A | GCR | PDC | VBI | VEIL | VITC | WSS | XDS |
| Digital broadcast |
| Interlaced: SDTV (480i, 576i) | HDTV (1080i) |
| Progressive: LDTV (240p, 288p, 1seg) | EDTV (480p, 576p) | HDTV (720p, 1080p) |
| Digital TV standards: MPEG-2: ATSC, DVB, ISDB | MPEG-4: SBTVD |
| Multichannel audio: AAC (5.1) | Musicam | PCM | LPCM |
| Hidden signals: Captioning | Teletext | (CPCM/Broadcast flag) | AFD | EPG |
| Digital cinema: UHDV (2540p, 4320p) | DCI | 22.2 audio |
| Technical issues: | MPEG transport | Standards conversion | Video processing | VOD |
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For other uses, see Mechanic (disambiguation).
Mechanics (Greek Μηχανική
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Electronics is the study of the flow of charge through various materials and devices such as, semiconductors, resistors, inductors, capacitors, nano-structures, and vacuum tubes. All applications of electronics involve the transmission of power and possibly information.
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Greek}}}
Writing system: Greek alphabet
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Official language of: Greece
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European Union
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Writing system: Greek alphabet
Official status
Official language of: Greece
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Latin}}}
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Official language of: Vatican City
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Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
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In psychology, visual perception is the ability to interpret visible light information reaching the eyes which is then made available for planning and action. The resulting perception is also known as eyesight, sight or vision.
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abbreviation (from Latin brevis "short") is a shortened form of a word or phrase. Usually, but not always, it consists of a letter or group of letters taken from the word or phrase. For example, the word "abbreviation" can itself be represented by the abbreviation "abbr.
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Mechanical television was a television system that used mechanical or electromechanical devices to capture and display images. However, the images themselves were usually transmitted electronically and via radio waves.
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Photoconductivity is an optical and electrical phenomenon in which a material becomes more conductive due to the absorption of electro-magnetic radiation such as visible light, ultraviolet light, infrared light,or gamma radiation.
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4, 6
(strongly acidic oxide)
Electronegativity 2.55 (scale Pauling)
Ionization energies
(more) 1st: 941.0 kJmol−1
2nd: 2045 kJmol−1
3rd: 2973.
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(strongly acidic oxide)
Electronegativity 2.55 (scale Pauling)
Ionization energies
(more) 1st: 941.0 kJmol−1
2nd: 2045 kJmol−1
3rd: 2973.
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Willoughby Smith (April 6, 1828, Great Yarmouth, England — July 17, 1891, Eastbourne, England) was an electrical engineer who discovered the photoconductivity of the element selenium.
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A Nipkow disk (sometimes Anglicized as Nipkov disk) is a mechanical, geometrically operating image scanning device, invented by Paul Gottlieb Nipkow. This scanning disk was a fundamental component in mechanical television through the 1920s.
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Paul Julius Gottlieb Nipkow (22 August 1860, Lauenburg, Pomerania - 24 August 1940, Berlin) was a German technician and inventor.
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Beginnings
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Anthem
"Das Lied der Deutschen" (third stanza)
also called "Einigkeit und Recht und Freiheit"
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"Das Lied der Deutschen" (third stanza)
also called "Einigkeit und Recht und Freiheit"
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In engineering, electromechanics combines the sciences of electromagnetism of electrical engineering and mechanics. Mechatronics is the discipline of engineering that combines mechanics, electronics and information technology (software engineering).
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Rasterization or rasterisation is the task of taking an image described in a vector graphics format (shapes) and converting it into a raster image (pixels or dots) for output on a video display or printer.
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Constantin Perskyi (Константин Дмитриевич Перский) was a Russian scientist who is credited with coining the word
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The Exposition Universelle of 1900 was a world's fair held in Paris, France, to celebrate the achievements of the past century and to accelerate development into the next. The style that was universally present in the Exposition was Art Nouveau.
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Ville de Paris
City flag City coat of arms
Motto: Fluctuat nec mergitur
(Latin: "Tossed by the waves, she does not sink")
The Eiffel Tower in Paris, as seen from the esplanade du Trocadéro.
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City flag City coat of arms
Motto: Fluctuat nec mergitur
(Latin: "Tossed by the waves, she does not sink")
The Eiffel Tower in Paris, as seen from the esplanade du Trocadéro.
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August 25 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.
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Events
- 325 - Council of Nicea convened by Emperor Constantine.
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19th century - 20th century
1870s 1880s 1890s - 1900s - 1910s 1920s 1930s
1897 1898 1899 - 1900 - 1901 1902 1903
Year 1900 (MCM
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1870s 1880s 1890s - 1900s - 1910s 1920s 1930s
1897 1898 1899 - 1900 - 1901 1902 1903
Year 1900 (MCM
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Halftone is the reprographic technique that simulates continuous tone imagery through the use of equally spaced dots of varying size.[1] 'Halftone' can also be used to refer specifically to the image that is produced by this process.
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Telegraphy (from the Greek words (τηλη) = far and (γραφειν) = write) is the long-distance transmission of written messages without physical transport of letters, originally by changing something that could
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Boris Lvovich Rosing (Russian: Бори́с Льво́вич Ро́зинг
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Vladimir Kozmich Zworykin (Russian: Владимир Козьмич Зворыкин
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1. Electron guns 2. Electron beams 3. Focusing coils 4. Deflection coils 5. Anode connection 6. Mask for separating beams for red, green, and blue part of displayed image 7.
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4, 6
(strongly acidic oxide)
Electronegativity 2.55 (scale Pauling)
Ionization energies
(more) 1st: 941.0 kJmol−1
2nd: 2045 kJmol−1
3rd: 2973.
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(strongly acidic oxide)
Electronegativity 2.55 (scale Pauling)
Ionization energies
(more) 1st: 941.0 kJmol−1
2nd: 2045 kJmol−1
3rd: 2973.
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March 25 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.
March 25
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