History of Television Essay Example

History of Television Essay Example History of Television Essay History of Television Essay The beginnings of mechanical television can be traced back to the discovery of the photoconductivity of the element selenium by Willoughby Smith in 1873, the invention of a scanning disk by Paul Gottlieb Nipkow in 1884 and John Logie Bairds demonstration of televised moving images in 1926. As 23-year-old German university student, Paul Nipkow proposed and patented the first electromechanical television system in 1884. 1] Although he never built a working model of the system, variations of Nipkows spinning-disk image rasterizer for television became exceedingly common, and remained in use until 1939. [2] 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. Perskyis paper reviewed the existing electromechanical technologies, mentioning the work of Nipkow and others. 3] The photoconductivity of selenium and Nipkows 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, composed of equally spaced dots of varying size, were being transmitted by facsimile over telegraph and telephone lines as a newspaper service. [4] However, it was not until 1907 that developments in amplification tube technology, by Lee DeForest and Arthur Korn among others, made the design practical. 4] The first demonstration of the instantaneous transmission of still silhouette 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. [5] In 1911, Boris Rosing and his student Vladimir Zworykin created a television system that used a mechanical m irror-drum scanner to transmit, in Zworykins words, very crude images over wires to the Braun tube (cathode ray tube or CRT) in the receiver. Moving images were not possible because, in the scanner, the sensitivity was not enough and the selenium cell was very laggy. 6] On March 25, 1925, Scottish inventor John Logie Baird gave the first public demonstration of televised silhouette images in motion, at Selfridges Department Store in London. [7] ATTs Bell Telephone Laboratories transmitted halftone still images of transparencies in May 1925. On June 13 of that year, Charles Francis Jenkins transmitted the silhouette image of a toy windmill in motion, over a distance of five miles from a naval radio station in Maryland to his laboratory in Washington, using a lensed disk scanner with a 48-line resolution. 8][9] However, if television is defined as the live transmission of moving images with continuous tonal variation, Baird first achieved this privately on October 2, 1925. But 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 rat e to 12. 5 images per second. Then he gave the worlds first 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, Bairds 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. [citation needed] In 1927, Baird transmitted a signal over 438 miles (705 km) of telephone line between London and Glasgow. In 1928, Bairds 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, Baird developed a video disk recording system dubbed Phonovision; a number of the Phonovision recordings, dating back to 1927, still exist. 10] In 1929, he became involved in the first experimental electromechanical television service in Germany. In November of the same year, Baird and Bernard Natan of Pathe established Frances first television company, Television-Baird-Natan. In 1931, he made the first outdoor remote broadcast, of the Epsom Derby. [11] In 1932, he demonstrated ultra-short wave television. Bairds electromechanical system reached a peak of 240 lines of resolution on BBC television broadcasts in 1936 thou gh the mechanical system did not scan the televised scene directly. Instead a 35 mm film was shot, rapidly developed and then scanned while the film was still wet. This intermediate film system was discontinued within three months in favor of a 405-line all-electronic system developed by Marconi-EMI. [12] Herbert E. Ives and Frank Gray of Bell Telephone Laboratories gave a dramatic demonstration of mechanical television on April 7, 1927. The reflected-light television system included both small and large viewing screens. The small receiver had a two-inch-wide by 2. 5-inch-high screen. The large receiver had a screen 24 inches wide by 30 inches high. Both sets were capable of reproducing reasonably accurate, monochromatic moving images. Along with the pictures, the sets also received synchronized sound. The system transmitted images over two paths: first, a wire link from Washington to New York City, then a radio link from Whippany, New Jersey. Comparing the two transmission methods, viewers noted no difference in quality. Subjects of the telecast included Secretary of Commerce Herbert Hoover. A flying-spot scanner beam illuminated these subjects. The scanner that produced the beam had a 50-aperture disk. The disc revolved at a rate of 18 frames per second, capturing one frame about every 56 milliseconds. (Todays systems typically transmit 30 or 60 frames per second, or one frame every 33. 3 or 16. 7 milliseconds respectively. ) Television historian Albert Abramson underscored the significance of the Bell Labs demonstration: It was in fact the best demonstration of a mechanical television system ever made to this time. It would be several years before any other system could even begin to compare with it in picture quality. [13] Meanwhile in the Soviet Union, Leon Theremin had been developing a mirror drum-based television, starting with 16 lines resolution in 1925, then 32 lines and eventually 64 using interlacing in 1926, and as part of his thesis on May 7, 1926 he electrically transmitted and then projected near-simultaneous moving images on a five foot square screen. 9] By 1927 he achieved an image of 100 lines, a resolution that was not surpassed until 1931 by RCA, with 120 lines. [citation needed] On December 25, 1926, Kenjiro Takayanagi demonstrated a television system with a 40-line resolution that employed a Nipkow disk scanner and CRT display at Hamamatsu Industrial High School in Japan. This protype is still on display at the Takayanagi Memorial Museum in Shizuoka University, Hamamatsu Campus. His research in creating a production model were halted by the US after Japan lost World War II. [14] Mechanical scanning systems, though obsolete for the more familiar television systems, nevertheless survive in long wave infra red cameras because there is no suitable all-electronic pickup device. http://en. wikipedia. org/wiki/History_of_television