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ansmission technology to date, including TV. Thisis the concept of "rasterization", the process ofconverting a visual image into a stream of

electrical pulses.

In 1884,Paul Gottlieb Nipkow, a 23-year-olduniversity student in Germany,[6]patented the firstelectromechanical TV system which employedascanning disk,a spinning disk with a series ofholes spiraling toward the center, for

rasterization. The holes were spaced atequal angularintervals such that, in a singlerotation, the disk would allow light to pass througheach hole and onto a light-sensitive seleniumsensor which produced theelectrical pulses. As an image was focused onthe rotating disk, each hole captured a horizontal

"slice" of the entire image.[7]

The first demonstration ofthe instantaneoustransmission of images withscanning and refresh was by Georges Rignouxand A. Fournier in Paris in 1909. A matrix of64seleniumcells, individually wired to a

mechanicalcommutator, served as anelectronicretina. In the receiver, a type ofKerrcellmodulated the light and a series of variouslyangled mirrors attached to the edge of a rotatingdisc scanned the modulated beam onto the

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display screen. A separate circuit regulatedsynchronization. The 8x8pixelresolution in thisproof-of-concept demonstration was just sufficient

to clearly transmit individual letters of thealphabet. An updated image was transmitted"several times" each second.

[8][9]

Nipkow's design was not practical until advancesinamplifier tubetechnology became available.Later designs used a rotating mirror-drum

scanner to capture the image and a cathode raytube (CRT) as a display device, but movingimages were still not possible due to the poorsensitivity of theselenium sensors. In 1907,Russian scientistBoris Rosingbecame the firstinventor to use a CRT in the receiver of anexperimental television system. He used mirror-

drum scanning to transmit simple geometricshapes to the CRT.

[10]

Vladimir Zworykindemonstrates electronictelevision (1929).

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Using a Nipkow disk, Scottish inventorJohnLogie Bairdsuccessfully demonstrated thetransmission of moving silhouette images

inLondon in 1925[11]

and of moving,monochromatic images in 1926. Baird's scanningdisk produced an image of 30 lines resolution,

just enough to discern a human face, from adouble spiral of lenses.

[12]This demonstration by

Baird is generally agreed to be the world's firsttrue demonstration of TV, albeit a mechanical

form no longer in use. Remarkably, in 1927, Bairdalso invented the world's firstvideorecordingsystem, "Phonovision;" because thesignal produced by his 30-line equipment was intheaudio frequencyrange, he was able to captureit on 10-inchgramophone recordsusing

conventionalaudio recordingtechnology. Ahandful of Baird's Phonovision recordings surviveand were finally decoded and rendered intoviewable moving images in the 1990s usingmodern digital signal-processing technology.

[13]

In 1926, Hungarian engineerKlmnTihanyidesigned a television system utilizing fully

electronic scanning and display elements andemploying the principle of "charge storage" withinthe scanning (or "camera") tube.[14][15][16][17]

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On 25 December 1926, KenjiroTakayanagidemonstrated a TV system with a 40-line resolution that employed a CRT display at

Hamamatsu Industrial High School inJapan.

[18]This was the first working example of a

fully electronic television receiver. Takayanagi didnot apply for a patent.

[19]

By 1927, Russian inventorLonTheremindeveloped a mirror-drum-based TV

system which used interlacingto achieveanimage resolutionof 100 lines.[20]

Philo Farnsworth

In 1927,Philo Farnsworth made the world's firstworking television system with electronicscanning of both the pickup and displaydevices,[21]which he first demonstrated to thepress on 1 September 1928.

[21][22]

WRGBclaims to be the world's oldesttelevisionstation,tracing its roots to an experimental station

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founded on 13 January 1928, broadcasting fromthe General Electricfactory in Schenectady, NY,under the call letters W2XB.

[23]It was popularly

known as "WGY Television" after its sister radiostation. Later in 1928, General Electric started asecond facility, this one in New York City, whichhad the call lettersW2XBS and which today isknown asWNBC.

The two stations were experimental in nature and

had no regular programming, as receivers wereoperated by engineers within the company. Theimage of aFelix the Catdoll rotating on aturntable was broadcast for 2 hours every day forseveral years as new technology was beingtested by the engineers.Milton Berleclaimed thathe was involved in a very early television

experiment inChicago, Illinois, in 1929.[24]

At the Berlin Radio Show in August1931,Manfred von Ardenne gave the world's firstpublic demonstration of a TV system using acathode ray tube for both transmission andreception. The world's first electronically scanned

TV service began in Berlin in 1935. In August1936, theOlympic Gamesin Berlin were carriedby cable to TV stations in Berlin and Leipzigwhere the public could view the games live.

[25]

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In 1935, the German firm ofFernseh A.G.and theUnited States firm Farnsworth Television ownedbyPhilo Farnsworth signed an agreement to

exchange their television patents and technologyto speed development of TV transmitters andstations in their respective countries.

[26]

On 2 November 1936, theBBC begantransmitting the world's first public regular high-definition service from the VictorianAlexandra

Palacein north London.

[27]

It therefore claims tobe the birthplace of TV broadcasting as we knowit today.

In 1936,Klmn Tihanyidescribed the principleof plasma display, the firstflat paneldisplaysystem.

[28][29]

Mexican inventorGuillermo GonzlezCamarenaalso played an important role in earlyTV. His experiments with TV (known astelectroescopa at first) began in 1931 and led toa patent for the "trichromatic field sequentialsystem"color televisionin 1940.

[30]

Although TV became more familiar to the general

public in the US at the 1939 World's Fair, theoutbreak ofWorld War II prevented it from beingmanufactured on a large scale until after the war'send. True regular commercialtelevisionnetworkprogramming did not begin in the US until

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1948. During that year, conductorArturoToscaninimade his first of ten TV appearancesconducting theNBC Symphony

Orchestra,[31]

and Texaco Star Theater,starringcomedian Milton Berle,became television's firstgigantic hit show.

[32]Since the 1950s, television

has been the main medium for molding publicopinion.

[1]

Amateur television(ham TVorATV) was

developed fornon-commercialexperimentation,pleasure, and public service events byamateurradiooperators. Ham TV stations were on the airin many cities before commercial TV stationscame on the air.

[33]

In 2012, it was reported that TV revenue wasgrowing faster than film for major media

companies.[34]

Color TV

Title card forNBC, promoting their broadcast"in RCAcolor".

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Color TV is part of thehistory of television,thetechnology of television,and practicesassociated with television's transmission

of moving images in color video.In its most basic form, a color broadcast can becreated by broadcasting three monochromeimages, one each in the three colors of red, greenand blue (RGB). When displayed together or ineither rapid succession or optically overlapped,

these images will blend together to produce a fullcolor image as seen by the viewer.

One of the great technical challenges ofintroducing color broadcast televisionwas thedesire to conservebandwidthpotentially threetimes that of the existing black-and-whitestandards and not use an excessive

amount of radio spectrum.In the US, afterconsiderable research, the National TelevisionSystems Committee (NTSC)

[35]approved an all-

electronic system developed byRCA whichencoded color difference information (renderingthe hue and saturation of colors) separately from

the brightness information (rendering thelightness and darkness of colors) and greatlyreduced the resolution of the color differenceinformation in order to conserve bandwidth. Thebrightness image remained compatible with

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existing black-and-white television sets at fullresolution, while color TVs could decode both theextra information (low resolution color difference)

and the brightness image and then combine thebrightness image with the color difference imageto produce a full-color image. The higherresolution black-and-white and lower resolutioncolor-difference images combine in the eye toproduce a seemingly high-resolution full-colorimage. TheNTSCstandard represented a major

technical achievement.

Although all-electronic color was introduced in theUS in 1953,

[36]high prices and the scarcity of

color programming greatly slowed its acceptancein the marketplace. The first national colorbroadcast (the 1954 Tournament of Roses

Parade) occurred on January 1, 1954, but duringthe following 10 years most network broadcasts,and nearly all local programming, continued to bein black-and-white. It was not until the mid-1960sthat color sets started selling in large numbers,due in part to the color transition of 1965 in whichit was announced that over half of all network

prime-time programming would be broadcast incolor that fall. The first all-color prime-timeseason came just one year later.

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Early color sets were either floor-standingconsole models or tabletop versions nearly asbulky and heavy, so in practice they remained

firmly anchored in one place. The introductionof GE's relatively compact and lightweightPorta-Color set in the spring of 1966 made watchingcolor television a more flexible and convenientproposition. In 1972, sales of color sets finallysurpassed sales of black-and-white sets. Also in1972, the last holdout among daytime network

programs converted to color, resulting in the firstcompletely all-color network season.

Color broadcasting in Europe was notstandardized on the PALformat until the 1960s,and broadcasts did not start until 1967. By thispoint many of the technical problems in the early

sets had been worked out, and the spread ofcolor sets in Europe was fairly rapid.

By the mid-1970s, the only stations broadcastingin black-and-white were a few high-numberedUHF stations in small markets and a handful oflow-power repeater stations in even smaller

markets such as vacation spots. By 1979, eventhe last of these had converted to color, and bythe early 1980s B&W sets had been pushed intoniche markets, notably low-power uses, smallportable sets, or use as video monitorscreens in

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lower-cost consumer equipment in the televisionproductionandpost-productionindustry.

Color bars used in a test pattern, sometimes usedwhen no program material is available.

Geographical usage

Television introduction by country

1930 to 1939 1980 to 1989

1940 to 1949 1990 to 1999

1950 to 1959 After 2000

1960 to 1969 No television

1970 to 1979 No data

Main article: Geographical usage of television Timeline of the introduction of television in

countries

Content

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ProgrammingSee also:TelevisionprogramandCategory:Television genres

Getting TV programming shown to the public canhappen in many different ways. After production,the next step is to market and deliver the productto whichever markets are open to using it. Thistypically happens on two levels:

1.Original Runor First Run: a producer

creates a program of one or multipleepisodes and shows it on a station ornetwork which has either paid for theproduction itself or to which a license hasbeen granted by thetelevision producers todo the same.

2.Broadcast syndication:this is theterminology rather broadly used to describesecondary programming usages (beyondoriginal run). It includes secondary runs inthe country of first issue but also internationalusage which may not be managed by theoriginating producer. In many cases, other

companies, TV stations, or individuals areengaged to do the syndication work, in otherwords, to sell the product into the marketsthey are allowed to sell into by contract from

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the copyright holders, in most cases theproducers.

First-run programming is increasing on

subscription services outside the US, but fewdomestically produced programs are syndicatedon domestic free-to-air(FTA) elsewhere. Thispractice is increasing however, generally ondigital-only FTA channels or with subscriber-onlyfirst-run material appearing on FTA.

Unlike the US, repeat FTA screenings of an FTAnetwork program usually only occur on thatnetwork. Also,affiliatesrarely buy or producenon-network programming that is not centeredaroundlocal programming.

Funding

The examples and perspective inthis section may not representaworldwide viewof thesubject. Pleaseimprove thisarticleand discuss the issue onthe talk page. (January 2010)

Television sets per 1000 people of the world

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1000+ 100200

5001000 50100

300500 050

200

300 No data

Around the globe, broadcast TV is financed bygovernment, advertising, licensing (a form of tax),subscription, or any combination of these. Toprotect revenues, subscription