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La '''television''' es la transmission, per cable o alara per las ondas radioelectricas, d'unes imatges ou de scènas animadas e que son generalament sonorizadas. Son reproduïdas sus un receptor que se sona normalament [[televisor]] (pasmens se ditz sovent colloquialament television), a flor e mesura que son recebudas. Los primièrs passes de la vision a distància per l'electricitat son lo [[telectroscòpi]] puèi la television. La television, coma la coneissèm uèi, es tanben tributària d'una ret economica ([[publicitat]] e/o [[redevància]] dins qualques païses coma França), politica e culturala ([[lenga d'estat|lengas d'estat]] o minorizadas, genres e formats).
[[File:Old television.jpg|thumb]]
[[File:Oi TV.svg|thumb|1x1px]]
qualques païses coma França), politica e culturala ([[lenga d'estat|lengas d'estat]] o minorizadas, genres e formats).In its early stages of development, TV employed a combination of optical, mechanical and electronic technologies to capture, transmit and display a visual image. By the late 1920s, those employing only optical and electronic technologies were being explored. All modern TV systems relied on the latter, although the knowledge gained from the work on electromechanical systems was crucial in the development of fully electronic television.
 
Braun HF 1 television receiver, Germany, 1958
 
The first images transmitted electrically were sent by early mechanical fax machines, including the pantelegraph, developed in the late 19th century. The concept of electrically powered transmission of TV images in motion was first sketched in 1878 as the telephonoscope, shortly after the invention of the telephone. At the time, it was imagined by early science fiction authors, that someday that light could be transmitted over copper wires, as sounds were.
 
The idea of using scanning to transmit images was put to actual practical use in 1881 in the pantelegraph, through the use of a pendulum-based scanning mechanism. From this period forward, scanning, in one form or another has been used in nearly every image transmission technology to date, including TV. This is the concept of "rasterization", the process of converting a visual image into a stream of electrical pulses.
 
In 1884, Paul Gottlieb Nipkow, a 23-year-old university student in Germany,<sup>[6]</sup> patented the first electromechanical TV system which employed a scanning disk, a spinning disk with a series of holes spiraling toward the center, for rasterization. The holes were spaced at equal angular intervals such that, in a single rotation, the disk would allow light to pass through each hole and onto a light-sensitive selenium sensor which produced the electrical pulses. As an image was focused on the rotating disk, each hole captured a horizontal "slice" of the entire image.<sup>[7]</sup>
 
Nipkow's design was not practical until advances in amplifier tube technology became available. Later designs used a rotating mirror-drum scanner to capture the image and a cathode ray tube (CRT) as a display device, but moving images were still not possible, due to the poor sensitivity of the selenium sensors. In 1907, Russian scientist Boris
[[File:CRT Television.jpg|thumb]]
Rosing became the first inventor to use a CRT in the receiver of an experimental television system. He used mirror-drum scanning to transmit simple geometric shapes to the CRT.<sup>[8]</sup>
 
Vladimir Zworykindemonstrates electronic television (1929).
 
Using a Nipkow disk, Scottish inventor John Logie Baird succeeded in demonstrating the transmission of moving silhouette images inLondon in 1925,<sup>[9]</sup> and of moving, monochromatic images in 1926. Baird's scanning disk produced an image of 30 lines resolution, just enough to discern a human face, from a double spiral of Photographic lenses.<sup>[10]</sup> This demonstration by Baird is generally agreed to be the world's first true demonstration of TV, albeit a mechanical form no longer in use. Remarkably, in 1927, Baird also invented the world's first video recording system, "Phonovision": by modulating the output signal of his TV camera down to the audio range, he was able to capture the signal on a 10-inch wax audio disc using conventional audio recording technology. A handful of Baird's 'Phonovision' recordings survive and these were finally decoded and rendered into viewable images in the 1990s using modern digital signal-processing technology.<sup>[11]</sup>
 
In 1926, Hungarian engineer Kálmán Tihanyi designed a television system utilizing fully electronic scanning and display elements, and employing the principle of "charge storage" within the scanning (or "camera") tube.<sup>[12][13][14][15]</sup>
 
On 25 December 1926, Kenjiro Takayanagi demonstrated a TV system with a 40-line resolution that employed a CRT display at Hamamatsu Industrial High School in Japan.<sup>[16]</sup> This was the first working example of a fully electronic television receiver. Takayanagi did not apply for a patent.<sup>[17]</sup>
 
By 1927, Russian inventor Léon Theremin developed a mirror-drum-based TV system which used interlacing to achieve an image resolution of 100 lines.<sup>[18]</sup>
 
Philo Farnsworth
 
In 1927, Philo Farnsworth made the world's first working television system with electronic scanning of both the pickup and display devices,<sup>[19]</sup> which he first demonstrated to the press on 1 September 1928.<sup>[19][20]</sup>
 
WRGB claims to be the world's oldest television station, tracing its roots to an experimental station founded on 13 January 1928, broadcasting from the General Electric factory in Schenectady, NY, under the call letters W2XB.<sup>[21]</sup> It was popularly known as "WGY Television" after its sister radio station. Later in 1928, General Electric started a second facility, this one in New York City, which had the call letters W2XBS, and which today is known as WNBC.
 
The two stations were experimental in nature and had no regular programming, as receivers were operated by engineers within the company. The image of a Felix the Cat doll, rotating on a turntable, was broadcast for 2 hours every day for several years, as new technology was being tested by the engineers. Milton Berle claimed that he was on a very
 
early experimental television experiment inChicago, Illinois, in 1929.<sup>[22][23]</sup>
 
At the Berlin Radio Show in August 1931, Manfred von Ardenne gave the world's first public demonstration of a TV system using a cathode ray tube for both transmission and reception. The world's first electronically scanned TV service began in Berlin in 1935. In August 1936, the Olympic Games in Berlin were carried by cable to TV stations in Berlin and Leipzig where the public could view the games live.<sup>[24]</sup>
 
In 1935, the German firm of Fernseh A.G. and the United States firm Farnsworth Television owned by Philo Farnsworth signed an agreement to exchange their television patents and technology to speed development of TV transmitters and stations in their respective countries.<sup>[25]</sup>
 
On 2 November 1936, the BBC began transmitting the world's first public regular high-definition service from the Victorian Alexandra Palace in north London.<sup>[26]</sup> It therefore claims to be the birthplace of TV broadcasting as we know it today.
 
In 1936, Kálmán Tihanyi described the principle of plasma display, the first flat panel display system.<sup>[27][28]</sup>
 
Mexican inventor Guillermo González Camarena also played an important role in early TV. His experiments with TV (known as telectroescopía at first) began in 1931 and led to a patent for the "trichromatic field sequential system" color television in 1940.<sup>[29]</sup>
 
Although TV became more familiar in the US with the general public at the 1939 World's Fair, the outbreak of World War II prevented it from being manufactured on a large scale until after war's end. True regular commercial television network programming did not begin in the US until 1948. During that year, conductor Arturo Toscanini made his first of ten TV appearances conducting the NBC Symphony Orchestra,<sup>[30]</sup> and ''Texaco Star Theater'', starring comedian Milton Berle, became television's first gigantic hit show.<sup>[31]</sup> Since the 1950s, television has been the main medium for molding public opinion.<sup>[1]</sup>
 
Amateur television (''ham TV'' or ''ATV'') was developed for non-commercial experimentation, pleasure and public service events by amateur radio operators. Ham TV stations were on the air in many cities before commercial TV stations came on the air.<sup>[32]</sup>
 
In 2012, it was reported that TV revenue was growing faster than film for major media companies.<sup>[33]</sup>
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Recuperada de « https://oc.wikipedia.org/wiki/Television »