Difference between revisions of "Television" - New World Encyclopedia

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[[Image:523 Samsung 82inch 500x317px.jpg|thumb|right|400px|A modern 82" (208 cm) LCD television.]]
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[[Image:523 Samsung 82inch 500x317px.jpg|thumb|right|400px|An 82-inch (208-centimeter) LCD television.]]
[[Image:Hd tv samsung LE26R41BD.jpg|thumb|250px|right|[[Samsung Electronics|Samsung]] LE26R41BD [[High-definition television|HDTV]]]]
 
  
'''Television''' is a [[telecommunication]] system for [[broadcasting]] and receiving [[Film|moving picture]]*s and [[sound]] over a distance. The term has come to refer to all the aspects of television from the [[television set]]* to the [[television program|programming]]* and [[Transmission (telecommunications)|transmission]]*. The word is derived from mixed [[Latin]] and [[Greek language|Greek]] roots, meaning "far sight": Greek "tele",  far, and Latin "visio-n", sight (from ''video, vis-'' to see).
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'''Television''' (or '''TV''') (from the Greek ''tele'', meaning "far," and the [[Latin]] ''visio'', meaning "sight") is a [[telecommunication]] system for [[broadcasting]] and receiving [[Film|moving picture]]s and [[sound]] over long distances. The term has come to refer to all aspects of the system, from the receiver set to the [[television program|programming]] and [[Transmission (telecommunications)|transmission]].
 
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{{toc}}
With the television industry growing and becoming more used in every aspect of our lives, it is not surprising to see televisions being one of the highest bought items.  It is even used as an economic indicator as to how many televisions are sold. Almost every household in the United States has at least one television set. The average household might have 2-3 televisions.  You can find a television in any given room in a home, including the bathroom.
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With the growth and influence of the television industry, it is not surprising that TV sets rank among consumer goods purchased most often, and the number of sets sold per year is used as an economic indicator. Almost every household in the United States has at least one television set. The average household might have two or three, with a set even in the bathroom.
 
 
In the future, with prices going down and new technology growing every day, it can be imagined that some day the liquid crystal display (LCD) or plasma television could completely make the CRT television obsolete, much in the same way CDs overtook vinyl records.
 
  
 
== History ==
 
== History ==
:{{Main article|History of television}}
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[[Image:OTVbelweder-front.jpg|250px|thumb|right|A Belweder TV set (OT-1471), Poland, 1957.<br/>
 
 
[[Image:OTVbelweder-front.jpg|250px|thumb|right|A Belweder TV set (OT-1471), Poland, 1957.<br>
 
 
{{col-begin}}
 
{{col-begin}}
 
{{col-break}}
 
{{col-break}}
1. power switch / volume<br>
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1. power switch / volume<br/>
2. brightness<br>
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2. brightness<br/>
3. pitch<br>
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3. pitch<br/>
4. vertical synchro<br>
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4. vertical synchro<br/>
 
{{col-break}}
 
{{col-break}}
5. horizontal synchro<br>
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5. horizontal synchro<br/>
6. contrast<br>
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6. contrast<br/>
7. channel tuning<br>
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7. channel tuning<br/>
8. channel switch</small>
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8. channel switch
 
{{col-end}}]]
 
{{col-end}}]]
[[Image:1950's television.jpg|thumb|250px|A 1950s television set.]]
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[[Image:1950's television.jpg|thumb|250px|A 1950s television set]]
  
 
The television was not invented by a single person, but by a number of scientists' advancements contributing to the ultimate all-electronic version of the invention. The origins of what would become today's television system can be traced back as far as the discovery of the [[photoconductivity]] of the element [[selenium]] by [[Willoughby Smith]] in 1873 followed by the work on the [[telectroscope]] and the invention of the scanning disk by [[Paul Nipkow]] in 1884. All practical television systems use the fundamental idea of scanning an image to produce a time series signal representation. That representation is then transmitted to a device to reverse the scanning process. The final device, the television (or T.V. set), relies on the human eye to integrate the result into a coherent image.
 
The television was not invented by a single person, but by a number of scientists' advancements contributing to the ultimate all-electronic version of the invention. The origins of what would become today's television system can be traced back as far as the discovery of the [[photoconductivity]] of the element [[selenium]] by [[Willoughby Smith]] in 1873 followed by the work on the [[telectroscope]] and the invention of the scanning disk by [[Paul Nipkow]] in 1884. All practical television systems use the fundamental idea of scanning an image to produce a time series signal representation. That representation is then transmitted to a device to reverse the scanning process. The final device, the television (or T.V. set), relies on the human eye to integrate the result into a coherent image.
  
[[Image:Early portable tv.jpg|thumb|240px|left|A transistor-based portable television, typical of NTSC models of the late 1960s and 1970s.]]
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[[Image:Early portable tv.jpg|thumb|240px|left|A transistor-based portable television, typical of NTSC models of the late 1960s and 1970s]]
[[Image:Braun HF 1.jpg|thumb|right|210px|Braun HF 1, Germany, 1958.]]
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[[Image:Braun HF 1.jpg|thumb|right|210px|Braun HF 1, Germany, 1958]]
  
Electromechanical techniques were developed from the 1900s into the 1920s, progressing from the transmission of still photographs, to live still duotone images, to moving duotone or silhouette images, with each step increasing the sensitivity and speed of the scanning photoelectric cell. [[John Logie Baird]] gave the world's first public demonstration of a working television system that transmitted live moving images with tone graduation (grayscale) on 26 January 1926 at his laboratory in London, and built a complete experimental broadcast system around his technology. Baird further demonstrated the world's first [[color]] television transmission on 3 July 1928. Other prominent developers of mechanical television included [[Charles Francis Jenkins]], who demonstrated a primitive television system in 1923, [[Frank Conrad]] who demonstrated a movie-film-to-television converter at [[Westinghouse]] in 1928, and [[Frank Gray]] and [[Herbert E. Ives]] at [[Bell Labs]] who demonstrated wired long-distance television in 1927 and two-way television in 1930.
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Electromechanical techniques were developed from the 1900s into the 1920s, progressing from the transmission of still photographs to live still duotone images to moving duotone or silhouette images, with each step increasing the sensitivity and speed of the scanning photoelectric cell. [[John Logie Baird]] gave the world's first public demonstration of a working television system that transmitted live moving images with tone graduation (grayscale) on January 26, 1926, at his laboratory in [[London]], and built a complete experimental broadcast system around his technology. Baird further demonstrated the world's first [[color]] television transmission on July 3, 1928. Other prominent developers of mechanical television included [[Charles Francis Jenkins]], who demonstrated a primitive television system in 1923, [[Frank Conrad]] who demonstrated a movie-film-to-television converter at [[Westinghouse]] in 1928, and [[Frank Gray]] and [[Herbert E. Ives]] at [[Bell Labs]] who demonstrated wired long-distance television in 1927 and two-way television in 1930.
  
Color television systems were invented and patented even before black-and-white television was working (see [[History of television]] for details).
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Color television systems were invented and patented even before black-and-white television was working.
  
Completely electronic television systems relied on the inventions of [[Philo Taylor Farnsworth]], [[Vladimir Zworykin]] and others to produce a system suitable for mass distribution of television programming. Farnsworth gave the world's first public demonstration of an all-electronic television system at the [[Franklin Institute]] in [[Philadelphia, Pennsylvania|Philadelphia]] on 25 August 1934.
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Completely electronic television systems relied on the inventions of [[Philo Taylor Farnsworth]], [[Vladimir Zworykin]] and others to produce a system suitable for mass distribution of television programming. Farnsworth gave the world's first public demonstration of an all-electronic television system at the [[Franklin Institute]] in [[Philadelphia, Pennsylvania|Philadelphia]] on August 25, 1934.
  
Regular broadcast programming occurred in the United States,<ref>[http://www.wrgb.com/community_history.shtml RGB History], [http://www.tvhistory.tv/W1XAY.htm How Television Came to Boston: The Forgotten Story of W1XAY], and [http://online.sfsu.edu/~hl/cfj/cfj.W3XK.html W3XK — America's first television station].</ref> the United Kingdom,<ref>[http://www.bairdtelevision.com/1932.html J.L. Baird: Television in 1934].</ref> Germany,<ref>[http://www.museum.tv/archives/etv/G/htmlG/germany/germany.htm Museum of Broadcast Communications: Germany] and [http://www.tvhistory.tv/1936%20German%20Olympics%20TV%20Program.htm Berlin 1936: Television in Germany].</ref> France,<ref>[http://www.earlytelevision.org/eiffel_transmitter_1.html The Eiffel Tower Television Installation].</ref> and the Soviet Union<ref>R. W. Burns, ''Television: An International History of the Formative Years''. IET, 1998, p. 488. ISBN 0852969147, and [http://www.earlytelevision.org/rca_rr-359_russia.html RCA's Russian Television Connection].</ref> before World War II. The first regular television broadcasts with a modern level of definition (240 or more lines) were made in England in 1936, soon upgraded to the so-called "System A" with 405 lines. Regular network broadcasting began in the United States in 1946, and television became common in American homes by the middle 1950s. While North American over-the-air broadcasting was originally free of direct marginal cost to the consumer (i.e., cost in excess of acquisition and upkeep of the hardware) and broadcasters were compensated primarily by receipt of advertising revenue, increasingly United States television consumers obtain their programming by subscription to cable television systems or direct-to-home satellite transmissions. In the United Kingdom, France, and most of the rest of Europe, on the other hand, operators of television equipment must pay an annual [[Television licence|license fee]], which is usually used to fund (wholely or partly) the appropriate national public service broadcaster/s (e.g. [[BBC|British Broadcasting Corporation]], [[France Télévisions]], etc.).
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Regular broadcast programming occurred in the United States,<ref>Donna L. Halper, [http://www.tvhistory.tv/W1XAY.htm “How Television Came to Boston: The Forgotten Story of W1XAY.”] TVhistory.tv. Retrieved May 29, 2007.</ref><ref>H. A. Layer, [http://online.sfsu.edu/~hl/cfj/cfj.W3XK.html “Charles Francis Jenkins television station W3XK.] Retrieved May 29, 2007.</ref> the United Kingdom,<ref>[http://www.bairdtelevision.com/1932.html J. L. Baird: Television in 1934.] Bairdtelevision.com. Retrieved May 29, 2007.</ref> Germany,<ref>Joan Bleicher, [http://www.museum.tv/archives/etv/G/htmlG/germany/germany.htm Museum of Broadcast Communications: Germany.] Retrieved May 29, 2007.</ref><ref> [http://www.tvhistory.tv/1936%20German%20Olympics%20TV%20Program.htm 1936 German (Berlin) Olympics.] TVhistory.tv. Retrieved May 29, 2007.</ref> France and the Soviet Union<ref>R. W. Burns, ''Television: An International History of the Formative Years'' (IET, 1998, ISBN 0852969147), 488.</ref><ref>James O’Neal, [http://www.earlytelevision.org/rca_rr-359_russia.html RCA's Russian Television Connection.] Retrieved May 29, 2007.</ref> before [[World War II]]. The first regular television broadcasts with a modern level of definition (240 or more lines) were made in England in 1936, soon upgraded to the so-called "System A" with 405 lines.
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Regular network broadcasting began in the United States in 1946, and television became common in American homes by the middle 1950s. While North American over-the-air broadcasting was originally free of direct marginal cost to the consumer (cost in excess of acquisition and upkeep of the hardware) and broadcasters were compensated primarily by receipt of advertising revenue, increasingly United States television consumers obtain their programming by subscription to cable television systems or direct-to-home satellite transmissions. In the United Kingdom, France, and most of the rest of Europe, on the other hand, operators of television equipment must pay an annual [[Television licence|license fee]], which is usually used to fund (wholly or partly) the appropriate national public service broadcasters ([[BBC|British Broadcasting Corporation]], [[France Télévisions]], and so forth).
  
 
==Technology==
 
==Technology==
 
===Elements of a television system ===
 
===Elements of a television system ===
[[Image:Dv schnittplatz.JPG|thumb|250px|Digital video equipment in a cutting (editing) room.]]
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[[Image:Dv schnittplatz.JPG|thumb|250px|Digital video equipment in a cutting (editing) room]]
  
 
The elements of a simple television system are:
 
The elements of a simple television system are:
* An image source - this may be a [[Professional video camera|camera]] for live pick-up of images or a [[flying spot scanner]] for transmission of [[motion picture|films]]
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* An image source&mdash;this may be a [[Professional video camera|camera]] for live pick-up of images or a [[flying spot scanner]] for transmission of [[motion picture|films]]
* A sound source.
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* A sound source
* A [[transmitter]], which modulates one or more [[television signal]]s with both picture and sound information for transmission.
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* A [[transmitter]], which modulates one or more [[television signal]]s with both picture and sound information for transmission
* A receiver (television) which recovers the picture and sound signals from the television broadcast.
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* A receiver (television) which recovers the picture and sound signals from the television broadcast
* A display device, which turns the electrical signals into visible light.
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* A display device, which turns the electrical signals into visible light
* A sound device, which turns electrical signals into sound waves to go along with the picture.
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* A sound device, which turns electrical signals into sound waves to go along with the picture
  
Practical television systems include equipment for selecting different image sources, mixing images from several sources at once, insertion of pre-recorded video signals, synchronizing signals from many sources, and direct image generation by computer for such purposes as station identification. Transmission may be over the air from land-based transmitters, over metal or optical cables, or by radio from synchronous [[Satellite television|satellite]]s.   Digital systems may be inserted anywhere in the chain to provide better image transmission quality, reduction in transmission [[bandwidth]], special effects, or security of transmission from reception by non-subscribers.
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Practical television systems include equipment for selecting different image sources, mixing images from several sources at once, insertion of pre-recorded video signals, synchronizing signals from many sources, and direct image generation by computer for such purposes as station identification. Transmission may be over the air from land-based transmitters, over metal or optical cables, or by radio from synchronous [[Satellite television|satellite]]s. Digital systems may be inserted anywhere in the chain to provide better image transmission quality, reduction in transmission [[bandwidth]], special effects, or security of transmission from reception by non-subscribers.
<!-- Elements of a television system - block diagram here —>
 
<!-- Image source, camera, film, magnetic tape, exceptionally computer-generated images—>
 
<!-- Sound source —>
 
<!-- Transmitter, over the air, bandwidth required, antenna, satellite system, cable system, digital encoding, scrambling —>
 
<!-- Receiver, antenna, cable connection, satellite down-converter, digital decode, descramble—>
 
<!-- Display, cathode ray tube, color tube, now LCD, historically mechanical scanned lamp—>
 
<!-- Recorder, analogue magnetic tape, now digital —>
 
  
 
===Display technology===
 
===Display technology===
{{seealso|Liquid crystal display television}}
 
 
 
Thanks to advances in display technology, there are now several kinds of video displays used in modern TV sets:
 
Thanks to advances in display technology, there are now several kinds of video displays used in modern TV sets:
  
*'''CRT'''(Cathode Ray Tube): The most common screens are direct-view [[cathode ray tube|CRT]]s for up to 40 in (100 cm) (in 4:3) and 46 in (115 cm) (in 16:9) [[diagonal]]ly. These are the least expensive, and are a refined technology that can still provide the best value for overall picture quality. As they do not have a fixed [[native resolution]], they are capable of displaying sources with a variety of different resolutions at the best possible image quality. The [[frame rate]] or refresh rate of a typical [[NTSC]] format CRT TV is 60 Hz, and for the [[PAL]] format, is 50 Hz. A typical [[NTSC]] broadcast signal's visible portion has an equivalent resolution of about 640x480 pixels. It actually could be slightly higher than that, but the [[Vertical blanking interval|Vertical Blanking Interval]], or VBI, allows other signals to be carried along with the broadcast.
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*'''CRT''' (Cathode Ray Tube): The most common screens are direct-view [[cathode ray tube|CRT]]s for up to 40 inches (100 centimeters) (in 4:3) and 46 inches (115 centimeters) (in 16:9) diagonally. These are the least expensive and are a refined technology that can still provide the best value for overall picture quality. As they do not have a fixed [[native resolution]], they are capable of displaying sources with a variety of different resolutions at the best possible image quality. The [[frame rate]] or refresh rate of a typical [[NTSC]] format CRT TV is 60 Hz, and for the [[PAL]] format, is 50 Hz. A typical NTSC broadcast signal's visible portion has an equivalent resolution of about 640 by 480 pixels. It actually could be slightly higher than that, but the [[Vertical blanking interval|Vertical Blanking Interval]], or VBI, allows other signals to be carried along with the broadcast.
 
[[Image:CeBIT 2006 Philips 3D Display 42 3D6W01 WOW Richardson Electronics KUKFilm 1298 by HDTVTotalDOTcom.jpg|thumb|250px]]
 
[[Image:CeBIT 2006 Philips 3D Display 42 3D6W01 WOW Richardson Electronics KUKFilm 1298 by HDTVTotalDOTcom.jpg|thumb|250px]]
*'''Rear projection''': Most very large screen TVs (up to over 100&nbsp;inch (254 cm)) use [[projection]] technology. Three types of projection systems are used in projection TVs: CRT-based, [[Liquid crystal display|LCD]]-based, and [[DLP]] (reflective micromirror chip) -based. Projection television has been commercially available since the 1970s, but at that time could not match the image sharpness of the CRT; current models are vastly improved, and offer a cost-effective large-screen display.
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*'''Rear projection''': Most very large screen TVs (up to over 100 inches (254 cm)) use [[projection]] technology. Three types of projection systems are used in projection TVs: CRT-based, [[Liquid crystal display|LCD]]-based, and DLP (reflective micromirror chip) -based. Projection television has been commercially available since the 1970s, but at that time could not match the image sharpness of the CRT; current models are vastly improved, and offer a cost-effective large-screen display.
**A variation is a '''[[video projector]]''', using similar technology, which projects onto a [[Projection screen|screen]].
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**A variation is a '''video projector''', using similar technology, which projects onto a screen.
*'''Flat panel''' (LCD or plasma): Modern advances have brought [[Flat panel display|flat panel]]s to TV that use [[Active-matrix liquid crystal display|active matrix]] [[liquid crystal display|LCD]] or [[plasma display]] technology. Flat panel LCDs and [[plasma display]]s are as little as 1 inch thick and can be hung on a wall like a picture or put over a [[pedestal]]. Some models can also be used as [[Computer display|computer monitor]]s.
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*'''Flat panel''' (LCD or plasma): Modern advances have brought [[Flat panel display|flat panel]]s to TV that use [[Active-matrix liquid crystal display|active matrix]] [[liquid crystal display|LCD]] or [[plasma display]] technology. Flat panel LCDs and plasma displays are as little as one inch thick and can be hung on a wall like a picture or put over a [[pedestal]]. Some models can also be used as [[Computer display|computer monitor]]s.
*'''LED''' technology has become one of the choices for outdoor video and stadium uses, since the advent of ultra high brightness [[Light-emitting diode|LED]]s and driver circuits. LEDs enable scalable ultra-large [[Light-emitting diode#LED display panels|flat panel video displays]] that other existing technologies may never be able to match in performance.
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*'''LED''' technology has become one of the choices for outdoor video and stadium uses, since the advent of ultra high brightness [[Light-emitting diode|LED]]s and driver circuits. LEDs enable scalable ultra-large [[Light-emitting diode#LED display panels|flat panel video displays]] that other existing technologies may never be able to match in performance.
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Each has its pros and cons. Flat panel LCD displays can have narrow viewing angles and so may not suit a home environment. Rear projection screens do not perform well in natural daylight or well-lit rooms and thus are best suited to dark viewing areas.  
  
Each has its pros and cons. Flat panel LCD display can have narrow viewing angles and so may not suit a home environment. Rear projection screens do not perform well in natural [[daylight]] or well lit rooms and so are best suited to dark viewing areas. A complete run down of the [[Comparison of display technology|pros and cons]] of each display should be sought before purchasing a single television technology.
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[[Image:Hd tv samsung LE26R41BD.jpg|thumb|250px|right|[[Samsung Electronics|Samsung]] LE26R41BD [[High-definition television|HDTV]].]]
  
 
===Terminology for televisions===
 
===Terminology for televisions===
Pixel [[Display resolution|resolution]] is the amount of individual points known as [[pixels]] on a given screen. A typical resolution of 720x480 means that the television display has 720 pixels across and 480&nbsp;pixels on the vertical axis. The higher the resolution on a specified display the sharper the image.
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Pixel [[Display resolution|resolution]] is the amount of individual points known as [[pixels]] on a given screen. A typical resolution of 720 by 480 means that the television display has 720 pixels across and 480&nbsp;pixels on the vertical axis. The higher the resolution on a specified display the sharper the image.  
Contrast [[ratio]] is a measurement of the range between the brightest and darkest points on the screen. The higher the contrast ratio, the better looking picture there is in terms of richness, deepness, and [[shadow]] detail.
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Contrast [[ratio]] is a measurement of the range between the brightest and darkest points on the screen. The higher the contrast ratio, the better looking picture there is in terms of richness, deepness, and [[shadow]] detail.  
  
The [[brightness]] of a picture measures how vibrant and impacting the colours are. Measured in <math>cd/m^2</math> equivalent to the amount of candles required to power the [[image]].
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The [[brightness]] of a picture measures how vibrant and impacting the colors are. Measured in <math>cd/m^2</math> equivalent to the amount of candles required to power the [[image]].
  
 
===Transmission band===
 
===Transmission band===
There are various bands on which televisions operate depending upon the country. The [[VHF]] and [[UHF]] signals in bands III to V are generally used. Lower frequencies do not have enough [[bandwidth]] available for television. Although the [[BBC]] initially used Band I VHF at 45 MHz, this frequency is no longer in use for this purpose. Band II is used for FM radio transmissions. Higher frequencies behave more like light and do not penetrate buildings or travel around obstructions well enough to be used in a conventional broadcast TV system, so they are generally only used for satellite broadcasting, which uses frequencies around 10 GHz.   TV systems in most countries relay the video as an AM ([[amplitude-modulation]]) signal and the sound as a FM ([[frequency-modulation]]) signal. An exception is [[France]], where the sound is AM.
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There are various bands on which televisions operate depending upon the country. The [[VHF]] and [[UHF]] signals in bands III to V are generally used. Lower frequencies do not have enough [[bandwidth]] available for television. Although the [[BBC]] initially used Band I VHF at 45 MHz, this frequency is no longer in use for this purpose. Band II is used for FM radio transmissions. Higher frequencies behave more like light and do not penetrate buildings or travel around obstructions well enough to be used in a conventional broadcast TV system, so they are generally only used for satellite broadcasting, which uses frequencies around 10 GHz. TV systems in most countries relay the video as an AM ([[amplitude-modulation]]) signal and the sound as a FM ([[frequency-modulation]]) signal. An exception is [[France]], where the sound is AM.
  
 
===Aspect ratios===
 
===Aspect ratios===
'''[[Aspect ratio (image)|Aspect ratio]]''' refers to the ratio of the horizontal to vertical measurements of a television's picture. Mechanically scanned television as first demonstrated by [[John Logie Baird]] in 1926 used a 7:3 vertical aspect ratio, oriented for the head and shoulders of a single person in close-up.
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Aspect ratio refers to the ratio of the horizontal to vertical measurements of a television's picture. Mechanically scanned television as first demonstrated by [[John Logie Baird]] in 1926 used a 7:3 vertical aspect ratio, oriented for the head and shoulders of a single person in close-up.
  
Most of the early electronic TV systems from the mid-1930s onward shared the same [[aspect ratio (image)|aspect ratio]] of 4:3 which was chosen to match the [[Academy ratio|Academy Ratio]] used in cinema films at the time. This ratio was also square enough to be conveniently viewed on round [[cathode ray tube|cathode-ray tube]]s (CRTs), which were all that could be produced given the [[manufacturing]] [[technology]] of the time. (Today's CRT technology allows the manufacture of much wider tubes, and the flat-screen technologies which are becoming steadily more popular have no technical aspect ratio limitations at all.) The [[BBC]]'s television service used a more squarish 5:4 ratio from 1936 to 3 April 1950, when it too switched to a 4:3 ratio. This did not present significant problems, as most sets at the time used round tubes which were easily adjusted to the 4:3 ratio when the transmissions changed.
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Most of the early electronic TV systems from the mid-1930s onward shared the same aspect ratio of 4:3, which was chosen to match the Academy Ratio used in cinema films at the time. This ratio was also square enough to be conveniently viewed on round [[cathode ray tube|cathode-ray tube]]s (CRTs), which were all that could be produced given the [[manufacturing]] [[technology]] of the time (today's CRT technology allows the manufacture of much wider tubes, and the flat-screen technologies which are becoming steadily more popular have no technical aspect ratio limitations at all). The [[BBC]]'s television service used a more squarish 5:4 ratio from 1936 to April 3, 1950, when it too switched to a 4:3 ratio. This did not present significant problems, as most sets at the time used round tubes which were easily adjusted to the 4:3 ratio when the transmissions changed.
  
In the 1950s, [[movie studio]]s moved towards [[widescreen]] aspect ratios such as [[CinemaScope]] in an effort to distance their product from television. Although this was initially just a [[gimmick]], widescreen is still the format of choice today and square aspect ratio movies are rare. Some people argue that widescreen is actually a disadvantage when showing objects that are tall instead of [[panorama|panoramic]], others say that natural vision is more panoramic than tall, and therefore widescreen is easier on the eye.
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In the 1950s, movie studios moved towards [[widescreen]] aspect ratios such as CinemaScope in an effort to distance their product from television. Although this was initially just a [[gimmick]], widescreen is still the format of choice today and square aspect ratio movies are rare. Some people argue that widescreen is actually a disadvantage when showing objects that are tall instead of [[panorama|panoramic]], others say that natural vision is more panoramic than tall, and therefore widescreen is easier on the eye.
  
The switch to [[digital television]] systems has been used as an opportunity to change the standard television picture format from the old ratio of 4:3 (1.33:1) to an aspect ratio of 16:9 (approximately 1.78:1). This enables TV to get closer to the aspect ratio of modern widescreen [[film|movie]]s, which range from 1.66:1 through 1.85:1 to 2.35:1. There are two methods for transporting widescreen content, the better of which uses what is called [[full screen anamorphic|anamorphic widescreen]] format. This format is very similar to the technique used to fit a widescreen movie frame inside a 1.33:1 35mm film frame. The image is compressed horizontally when recorded, then expanded again when played back. The anamorphic widescreen 16:9 format was first introduced via European [[PALPlus]] television broadcasts and then later on "widescreen" [[DVD]]s; the [[ATSC]] [[High-definition television|HDTV]] system uses straight widescreen format, no horizontal compression or expansion is used.
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The switch to digital television systems has been used as an opportunity to change the standard television picture format from the old ratio of 4:3 (1.33:1) to an aspect ratio of 16:9 (approximately 1.78:1). This enables TV to get closer to the aspect ratio of modern widescreen [[film|movie]]s, which range from 1.66:1 through 1.85:1 to 2.35:1. There are two methods for transporting widescreen content, the better of which uses what is called [[full screen anamorphic|anamorphic widescreen]] format. This format is very similar to the technique used to fit a widescreen movie frame inside a 1.33:1 35 millimeter film frame. The image is compressed horizontally when recorded, then expanded again when played back. The anamorphic widescreen 16:9 format was first introduced via European PALPlus television broadcasts and then later on "widescreen" [[DVD]]s; the ATSC HDTV system uses straight widescreen format, no horizontal compression or expansion is used.
  
Recently "widescreen" has spread from television to computing where both [[desktop computer|desktop]] and [[laptop]] computers are commonly equipped with widescreen displays. There are some complaints about distortions of movie picture ratio due to some DVD playback software not taking account of aspect ratios; but this may subside as the DVD playback software matures. Furthermore, computer and laptop widescreen displays are in the 16:10 aspect ratio both physically in size and in pixel counts, and not in 16:9 of consumer televisions, leading to further complexity. This was a result of widescreen computer display engineers' uninformed assumption that people viewing 16:9 content on their computer would prefer that an area of the screen be reserved for playback controls, [[subtitles]] or their Taskbar, as opposed to viewing content full-screen.
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Widescreen spread from television to computing where both desktop and laptop [[computer]]s are commonly equipped with widescreen displays. There are some complaints about distortions of movie picture ratio due to some DVD playback software not taking account of aspect ratios, but this may subside as the DVD playback software matures. Furthermore, computer and laptop widescreen displays are in the 16:10 aspect ratio both physically in size and in pixel counts, and not in 16:9 of consumer televisions, leading to further complexity. This was a result of widescreen computer display engineers' uninformed assumption that people viewing 16:9 content on their computer would prefer that an area of the screen be reserved for playback controls, [[subtitles]] or their taskbar, as opposed to viewing content full-screen.
  
 
=====Aspect ratio incompatibility=====
 
=====Aspect ratio incompatibility=====
The television industry's changing of [[Aspect ratio (image)|aspect ratio]]s is not without difficulties, and can present a considerable problem.
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The television industry's changing of aspect ratios is not without difficulties, and can present a considerable problem.
  
 
Displaying a widescreen aspect (rectangular) image on a conventional aspect (square or 4:3) display can be shown:
 
Displaying a widescreen aspect (rectangular) image on a conventional aspect (square or 4:3) display can be shown:
*in "[[letterbox]]" format, with black horizontal bars at the top and bottom
+
*in "letterbox" format, with black horizontal bars at the top and bottom
*with part of the image being cropped, usually the extreme left and right of the image being cut off (or in "[[pan and scan]]", parts selected by an operator)
+
*with part of the image being cropped, usually the extreme left and right of the image being cut off (or in "pan and scan," parts selected by an operator)
 
*with the image horizontally compressed
 
*with the image horizontally compressed
  
 
A conventional aspect (square or 4:3) image on a widescreen aspect (rectangular with longer horizon) display can be shown:
 
A conventional aspect (square or 4:3) image on a widescreen aspect (rectangular with longer horizon) display can be shown:
*in "[[pillar box (film)|pillar box]]" format, with black vertical bars to the left and right
+
*in “pillar box" format, with black vertical bars to the left and right
*with upper and lower portions of the image cut off (or in "tilt and scan", parts selected by an operator)
+
*with upper and lower portions of the image cut off (or in "tilt and scan," parts selected by an operator)
 
*with the image horizontally distorted
 
*with the image horizontally distorted
  
A common compromise is to shoot or create material at an aspect ratio of 14:9, and to lose some image at each side for 4:3 presentation, and some image at top and bottom for 16:9 presentation. In recent years, the cinematographic process known as [[Super 35 mm film|Super 35]] (championed by [[James Cameron]]) has been used to film a number of major movies such as [[Titanic (1997 film)|''Titanic'']], ''[[Legally Blonde]]'', ''[[Austin Powers]]'', and ''[[Crouching Tiger, Hidden Dragon]]'' (see also: [[List of top-grossing films shot in Super 35]]). This process results in a camera-negative which can then be used to create both wide-screen theatrical prints, and standard "[[full screen]]" releases for television/VHS/DVD which avoid the need for either "[[Letterbox|letterboxing]]" or the severe loss of information caused by conventional "[[pan-and-scan]]" cropping.
+
A common compromise is to shoot or create material at an aspect ratio of 14:9, and to lose some image at each side for 4:3 presentation, and some image at top and bottom for 16:9 presentation. In recent years, the cinematographic process known as Super 35 (championed by [[James Cameron]]) has been used to film a number of major movies such as ''Titanic'', ''Legally Blonde'', ''Austin Powers'', and ''Crouching Tiger, Hidden Dragon''. This process results in a camera-negative which can then be used to create both wide-screen theatrical prints, and standard full screen releases for television/VHS/DVD which avoid the need for either "letterboxing" or the severe loss of information caused by conventional "pan-and-scan" cropping.
  
 
=== Sound ===
 
=== Sound ===
The sound provided by television was originally was similar to mono radio. Original televisions that were sold to the public were a small box that showed the image and was attached to a radio. One techinque for sound is called a simulcast (simultanious broadcast) where the sound is broadcast on radio while the video is broadcast on television. Some television stations use FM band to broadcast their sound. With televisions becoming more advanced, it is now quite common to have them with built in stereo. Many televisions today have stereo jacks so people can attach ampliphiers to the television for better sound.
+
The sound provided by television was originally was similar to monophonic [[radio]]. Original televisions that were sold to the public were a small box that showed the image and was attached to a radio. One technique for sound is called a simulcast (simultaneous broadcast) where the sound is broadcast on radio while the video is broadcast on television. Some television stations use FM band to broadcast their sound. With televisions becoming more advanced, it is now quite common to have them with built in stereo. Many televisions today have stereo jacks so people can attach amplifiers to the television for better sound.  
  
 
=== Television add-ons ===
 
=== Television add-ons ===
Today there are many television add-ons including [[Computer and video games|Video Game]] Consoles, [[Videocassette recorder|VCR]]s, [[Set-top box]]es for [[Cable television|Cable]], [[Satellite television|Satellite]] and DVB-T compliant [[Digital Television]] reception, [[DVD]] players, or [[Digital video recorder|Digital Video Recorders]] (including personal video recorders, PVRs). The add-on market continues to grow as new technologies are developed.
+
Today there are many television add-ons including [[Computer and video games|video game]] consoles, [[Videocassette recorder|VCR]]s, set-top boxes for [[cable television]], [[satellite]] and DVB-T compliant [[digital television]] reception, [[DVD]] players, or [[Digital video recorder|digital video recorders]] (including personal video recorders, PVRs). The add-on market continues to grow as new technologies are developed.
 
 
=== New developments ===
 
*Ambilight™
 
*Blu ray
 
*Broadcast flag
 
*CableCARD™
 
*DLP|Digital Light Processing (DLP)
 
*Digital Rights Management (DRM)
 
*Digital television (DTV)
 
*Digital Video Recorders (DVR)
 
*Direct Broadcast Satellite TV (DBS)
 
*DVD
 
*Flicker-free (100&nbsp;Hz or 120&nbsp;Hz, depending on country)
 
*HD DVD
 
*High Definition TV (HDTV)
 
*High-Definition Multimedia Interface (HDMI)
 
*IPTV
 
*Internet television]]
 
*LCD and plasma display flat screen TV
 
*SED display technology
 
*OLED display technology
 
*P2PTV
 
*Pay-per-view
 
*Personal video recorders (PVR)
 
*Picture-in-picture (PiP)
 
*Pixelplus
 
*Placeshifting
 
*Remote controls
 
*The Slingbox
 
*Timeshifting
 
*Video on-demand] (VOD)
 
*Ultra High Definition Video (UHDV)
 
*Web TV
 
  
 
=== Exterior designs ===
 
=== Exterior designs ===
In the early days of television, the cabinet was made of wood grain, however, the wood grain was disappearing in the 1980s.  However, there has been a modern comeback of the woodgrain.
+
In the early days of television, the cabinet was made of wood grain; however, the wood grain began to disappear in the 1980s, being replaced by streamlined plastic exteriors.  
  
 
==Content==
 
==Content==
 
===Advertising===
 
===Advertising===
Since their inception in the USA in 1940, [[television commercial|TV commercial]]s have become one of the most effective, most pervasive, and most popular methods of selling products of many sorts, especially consumer goods. U.S. advertising rates are determined primarily by [[Nielsen Ratings]].
+
Since their inception in the U.S. in 1940, [[television commercial|TV commercial]]s have become one of the most effective, most pervasive, and most popular methods of selling products of many sorts, especially consumer goods. [[Advertising]] rates in the U.S. are determined primarily by [[Nielsen Ratings]].
  
 
===Programming===
 
===Programming===
Getting TV programming shown to the public can happen in many different ways. After production the next step is to market and deliver the product to whatever markets are open to using it. This typically happens on two levels:
+
Getting TV programming shown to the public can happen in many different ways. After production the next step is to market and deliver the product to whatever markets are open to using it. This typically happens on two levels:
  
#'''Original Run''' or '''First Run''' - a producer creates a program of one or multiple episodes and shows it on a station or network which has either paid for the production itself or to which a license has been granted by the producers to do the same.
+
#'''Original Run''' or '''First Run'''&mdash;a producer creates a program of one or multiple episodes and shows it on a station or network which has either paid for the production itself or to which a license has been granted by the producers to do the same.
#'''[[Television syndication|Syndication]]''' - this is the terminology rather broadly used to describe secondary programming usages (beyond original run). It includes secondary runs in the country of first issue, but also international usage which may or may not be managed by the originating producer. In many cases other companies, [[TV stations]] or individuals are engaged to do the syndication work, in other words to sell the product into the markets they are allowed to sell into by contract from the copyright holders, in most cases the producers.
+
#'''[[Television syndication|Syndication]]'''&mdash;this is the terminology rather broadly used to describe secondary programming usages (beyond original run). It includes secondary runs in the country of first issue, but also international usage which may or may not be managed by the originating producer. In many cases other companies, TV stations or individuals are engaged to do the syndication work, in other words to sell the product into the markets they are allowed to sell into by contract from the copyright holders, in most cases the producers.
In most countries, the first wave occurs primarily on [[Free-to-air|free-to-air (FTA)]] television, while the second wave happens on subscription TV and in other countries. In the U.S., however, the first wave occurs on the FTA networks and subscription services, and the second wave travels via all means of distribution.
 
  
First run programming is increasing on subscription services outside the U.S., but few domestically produced programs are syndicated on domestic FTA elsewhere. This practice is increasing however, generally on digital-only FTA channels, or with subscriber-only first run material appearing on FTA.
+
In most countries, the first wave occurs primarily on free-to-air (FTA) television, while the second wave happens on subscription TV and in other countries. In the U.S., however, the first wave occurs on the FTA networks and subscription services, and the second wave travels via all means of distribution.
  
Unlike the U.S., repeat FTA screenings of a FTA network program almost only occur on that network. Also, [[Affiliate]]s rarely buy or produce non-network programming that isn't centred around local events.
+
First-run programming is increasing on subscription services outside the U.S., but few domestically produced programs are syndicated on domestic FTA elsewhere. This practice is increasing however, generally on digital-only FTA channels, or with subscriber-only first run material appearing on FTA.
 +
 
 +
Unlike the U.S., repeat FTA screenings of a FTA network program almost only occur on that network. Also, [[affiliate]]s rarely buy or produce non-network programming that isn't centered around local events.
  
 
== Social aspects ==
 
== Social aspects ==
 +
Almost since the medium's inception there have been charges that some programming is, in one way or another, inappropriate, offensive, or [[decency|indecent]]. Critics such as Jean Kilborne have claimed that television, as well as other mass media images, harm the self image of young girls. Other commentators, such as Sut Jhally, make the case that television advertising in the U.S. has been so effective that happiness has increasingly come to be equated with the purchase of products. [[George Gerbner]] has presented evidence that the frequent portrayals of crime, especially minority crime, has led to the [[Mean World Syndrome]], the view among frequent viewers of television that crime rates are much higher than the actual data would indicate. In addition, a lot of television has been charged with presenting propaganda, political or otherwise, and being pitched at a low intellectual level. Paralleling television's growing primacy in family life and society, an increasingly vocal chorus of legislators, [[scientist]]s, and [[parent]]s is raising objections to the uncritical acceptance of the medium.
  
Almost since the medium's inception there have been charges that some programming is, in one way or another, inappropriate, offensive, or [[decency|indecent]]. Critics such as Jean Kilborne have claimed that television, as well as other mass media images, harm the self image of young girls.  Other commentators, such as Sut Jhally, make the case that television advertising in the U.S. has been so effective that happiness has increasingly come to be equated with the purchase of products. [[George Gerbner]] has presented evidence that the frequent portrayals of crime, especially minority crime, has led to the [[Mean World Syndrome]], the view among frequent viewers of television that crime rates are much higher than the actual data would indicate. In addition, a lot of television has been charged with presenting propaganda, political or otherwise, and being pitched at a low intellectual level. Paralleling television's growing primacy in family life and society, an increasingly vocal chorus of legislators, [[scientist]]s, and [[parent]]s is raising objections to the uncritical acceptance of the medium.
+
Fifty years of research on the impact of television on children's emotional and social development demonstrated that there are clear and lasting effects of viewing violence.<ref>Norma Pecora, John P. Murray and Ellen A. Wartella, ''Children and Television: 50 Years of Research'' (Lawrence Erlbaum Associates, 2006, ISBN 0805841393).</ref> In a study published in February 2006,<ref>''Media Psychology'' 8 (1): 25-37.</ref> the research team demonstrated that the brain activation patterns of children viewing violence show that children are aroused by the violence (increased heart rates), demonstrate fear (activation of the [[amygdala]], the "fight or flight" sensor in the brain) in response to the video violence, and store the observed violence in an area of the brain (the [[posterior cingulate]]) that is reserved for long-term memory of traumatic events.
 
 
=== Results of research ===
 
 
 
Fifty years of research on the impact of television on children's emotional and social development demonstrate that there are clear and lasting effects of viewing violence.<ref>Norma Pecora, John P. Murray, & Ellen A. Wartella, ''Children and Television: 50 Years of Research'', Erlbaum Press, June 2006</ref> In a study published in February 2006,<ref>''Media Psychology'', volume 8, number 1, pages 25-37</ref> the research team demonstrated that the brain activation patterns of children viewing violence show that children are aroused by the violence (increased heart rates), demonstrate fear (activation of the [[amygdala]], the "fight or flight" sensor in the brain) in response to the video violence, and store the observed violence in an area of the brain (the [[posterior cingulate]]) that is reserved for long-term memory of traumatic events.
 
  
A 23 February 2002 article in [http://www.sciam.com/print_version.cfm?articleID=0005339B-A694-1CC5-B4A8809EC588EEDF ''Scientific American''] suggested that compulsive television watching, [[television addiction]], was no different from any other [[addiction]], a finding backed up by reports of withdrawal symptoms among families forced by circumstance to cease watching.
+
A 2002 article in ''Scientific American'' suggested that compulsive television watching, [[television addiction]], was no different from any other [[addiction]], a finding backed up by reports of withdrawal symptoms among families forced by circumstance to cease watching.<ref>Robert Kubey and Mihaly Csikszentmihalyi, [http://www.sciam.com/print_version.cfm?articleID=0005339B-A694-1CC5-B4A8809EC588EEDF “Television Addiction is no Mere Metaphor.”] ''Scientific American'' (February 23, 2002). Retrieved May 29, 2007.</ref>
  
A longitudinal study in [[New Zealand]] involving 1,000 people (from childhood to 26 years of age) demonstrated that "television viewing in childhood and adolescence is associated with poor educational achievement by 26 years of age". In other words, the more the child watched television, the less likely he or she was to finish school and enroll in a [[university]].
+
A longitudinal study in [[New Zealand]] involving one thousand people (from childhood to 26 years of age) demonstrated that "television viewing in childhood and adolescence is associated with poor educational achievement by 26 years of age." In other words, the more the child watched television, the less likely he or she was to finish school and enroll in a [[university]].
  
In [[Iceland]], television broadcasting hours were restricted until 1984, with no television programs being broadcast on Thursday, or during the whole of July. Also, the [[Sweden|Swedish]] government imposed a total ban on [[advertising]] to [[children]] under twelve in 1991.
+
In [[Iceland]], television broadcasting hours were restricted until 1984, with no television programs being broadcast on Thursday, or during the whole of July. Also, the [[Sweden|Swedish]] government imposed a total ban on [[advertising]] to [[children]] under 12 in 1991.
 
   
 
   
Despite this research, some media scholars have dismissed such studies as flawed.<ref>David Gauntlett, "[http://www.theory.org.uk/david/effects.htm Ten Things Wrong With the Media 'Effects' Model]."</ref>
+
Despite this research, some media scholars have dismissed the studies as flawed.<ref>David Gauntlett, [http://www.theory.org.uk/david/effects.htm “Ten Things Wrong With the Media 'Effects' Model.”] University of Westminster. Retrieved May 29, 2007.</ref>
  
 
==Technology trends==
 
==Technology trends==
 +
In its infancy, television was an ephemeral medium. Fans of regular shows planned their schedules so that they could be available to watch their shows at their time of broadcast. The term “appointment television” was coined by marketers to describe this kind of attachment.
  
In its infancy, television was an ephemeral medium. Fans of regular shows planned their [[TV listings|schedules]] so that they could be available to watch their shows at their time of broadcast. The term ''appointment television'' was coined by marketers to describe this kind of attachment. 
+
The viewership's dependence on schedule lessened with the invention of programmable video recorders, such as the [[videocassette recorder]] and the [[digital video recorder]]. Consumers could watch programs on their own schedule once they were broadcast and recorded. Television service providers also offer [[video on demand]], a set of programs which could be watched at any time.
 
 
The viewership's dependence on schedule lessened with the invention of programmable video recorders, such as the [[Videocassette recorder]] and the [[Digital video recorder]]. Consumers could watch programs on their own schedule once they were broadcast and recorded. Television service providers also offer [[video on demand]], a set of programs which could be watched at any time.
 
  
 
Both [[mobile phone]] networks and the [[Internet]] are capable of carrying video streams. There is already a fair amount of Internet TV available, either live or as downloadable programs.
 
Both [[mobile phone]] networks and the [[Internet]] are capable of carrying video streams. There is already a fair amount of Internet TV available, either live or as downloadable programs.
 
== Footnotes ==
 
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== See also ==
 
== See also ==
Line 205: Line 149:
 
* [[Broadcasting]]
 
* [[Broadcasting]]
 
* [[Electronics]]
 
* [[Electronics]]
 +
 +
== Notes ==
 +
<div class="references-small">
 +
<references />
 +
</div>
  
 
== References ==
 
== References ==
 
+
* Abramson, Albert. ''The History of Television, 1942 to 2000''. Jefferson, NC: McFarland & Company, 2003. ISBN 0786412208
*[[Erik Barnouw]], ''Tube of Plenty: The Evolution of American Television'', Oxford University Press, 1992.
+
* Barnouw, Erik. ''Tube of Plenty: The Evolution of American Television''. New York: Oxford University Press, 1990. ISBN 0195064844
*[[Pierre Bourdieu]], ''On Television'', The New Press, 2001.
+
* Bourdieu, Pierre. ''On Television''. New York: The New Press, 1999. ISBN 1565845129
*Brooks, Tim and March, Earle, ''The Complete Guide to Prime Time Network and Cable TV Shows'', Ballantine, Eighth Edition, 2002.
+
* Brooks, Tim, and Earle March. ''The Complete Guide to Prime Time Network and Cable TV Shows''. Ballantine, 2002. ISBN 0345455428
*[[Guy Debord]], ''The Society of the Spectacle'', Zone Books, 1995.
+
* Burns, R.W. ''Television: An International History of the Formative Years''. IET, 1998. ISBN 0852969147
*[[Jacques Derrida]], [[Bernard Stiegler]], ''Echographies of Television'', Polity Press, 2002.
+
* Debord, Guy. ''The Society of the Spectacle''. Zone Books, 1995. ISBN 0942299795
*[[Jerry Mander]], ''Four Arguments for the Elimination of Television'', Perennial, 1978.
+
* Derrida, Jacques, and Bernard Stiegler. ''Echographies of Television''. Malden, MA: Blackwell Publishers, Inc., 2002. ISBN 074562037X
* [[Neil Postman]], ''[[Amusing Ourselves to Death]]: Public Discourse in the Age of Show Business''. Penguin USA, 1985. ISBN 0-670-80454-1
+
* Fisher David E., and Marshall J. Fisher. ''Tube: the Invention of Television''. Washington DC: Counterpoint, 1996. ISBN 1887178171
*Dr. Aric Sigman, ''Remotely Controlled: How Television Is Damaging Our Lives — And What We Can Do About It'', Vermilion, 2005.
+
* Mander, Jerry. ''Four Arguments for the Elimination of Television''. Reprint edition, 2002. New York: HarperPerennial, 1977. ISBN 0688082742
*Beretta E. Smith-Shomade, ''Shaded Lives: African-American Women and Television'', Rutgers University Press, 2002.
+
* Pecora, Norma, John P. Murray, and Ellen A. Wartella. ''Children and Television: 50 Years of Research''. Lawrence Erlbaum Associates, 2006. ISBN 0805841393
* Dr. Alan Taylor, ''We, the media, Pedagogic Intrusions into US Film and Television News Broadcasting Rhetorics'' Peter, Lang, Academic Book Publishers, 2005, pp. 418.
+
* Postman, Neil. ''Amusing Ourselves to Death: Public Discourse in the Age of Show Business''. Penguin USA, 1985. ISBN 0670804541
*David E. Fisher and Marshall J. Fisher, ''Tube: the Invention of Television'', Counterpoint, Washington D.C. USA, (1996) ISBN 1-887178-17-1
+
* Sigman, Aric. ''Remotely Controlled: How Television Is Damaging Our Lives''. Random House UK, 2007. ISBN 0091906903
*Albert Abramson, ''The History of Television, 1942 to 2000'', McFarland, Jefferson, NC, USA, and London (2003) ISBN 0-7864-1220-8
+
* Smith-Shomade, Beretta E. ''Shaded Lives: African-American Women and Television''. Piscataway, NJ: Rutgers University Press, 2002. ISBN 0813531055
 +
* Taylor, Alan. ''We, the Media: Pedagogic Intrusion into U.S. Mainstream Film and Television News Broadcasting Rhetorics''. Peter Lang Academic Book Publishers, 2005. ISBN 3631518528
  
 
==External links==
 
==External links==
 +
All retrieved October 16, 2013.
  
* [http://www.gooya.co.uk/worldtv.html A directory of world television channels]
+
* [http://www.gooya.co.uk/worldtv.html GOOYA (UK)] &ndash; A directory of world television channels
* [http://www.lcdplasmatvguide.com/ TV Type Guide]
+
* [http://www.tvhistory.tv/ Television History—The First 75 Years]
* [http://www.tvhistory.tv/ Television History — The First 75 Years]
 
* [http://www.museum.tv/archives/etv/index.html The Encyclopedia of Television] at the [[Museum of Broadcast Communications]]
 
* [http://www.mztv.com MZTV Museum of Television] Some of the rarest sets in America
 
* [http://www.metvwiki.com/index.php/Main_Page CNET News.com's Me TV Wiki] about the future of television.
 
  
 
[[Category:Physical sciences]]
 
[[Category:Physical sciences]]
[[Category:Social sciences]]
+
[[Category:Politics and social sciences]]
 
[[Category:Electronics]]
 
[[Category:Electronics]]
 
[[Category:Engineering]]
 
[[Category:Engineering]]
 
[[Category:Technology]]
 
[[Category:Technology]]
 +
[[Category:Communication]]
  
 
{{credit|93690256}}
 
{{credit|93690256}}

Revision as of 20:46, 21 October 2013

File:523 Samsung 82inch 500x317px.jpg
An 82-inch (208-centimeter) LCD television.

Television (or TV) (from the Greek tele, meaning "far," and the Latin visio, meaning "sight") is a telecommunication system for broadcasting and receiving moving pictures and sound over long distances. The term has come to refer to all aspects of the system, from the receiver set to the programming and transmission.

With the growth and influence of the television industry, it is not surprising that TV sets rank among consumer goods purchased most often, and the number of sets sold per year is used as an economic indicator. Almost every household in the United States has at least one television set. The average household might have two or three, with a set even in the bathroom.

History

A Belweder TV set (OT-1471), Poland, 1957.

1. power switch / volume
2. brightness
3. pitch
4. vertical synchro

5. horizontal synchro
6. contrast
7. channel tuning
8. channel switch

A 1950s television set

The television was not invented by a single person, but by a number of scientists' advancements contributing to the ultimate all-electronic version of the invention. The origins of what would become today's television system can be traced back as far as the discovery of the photoconductivity of the element selenium by Willoughby Smith in 1873 followed by the work on the telectroscope and the invention of the scanning disk by Paul Nipkow in 1884. All practical television systems use the fundamental idea of scanning an image to produce a time series signal representation. That representation is then transmitted to a device to reverse the scanning process. The final device, the television (or T.V. set), relies on the human eye to integrate the result into a coherent image.

A transistor-based portable television, typical of NTSC models of the late 1960s and 1970s
Braun HF 1, Germany, 1958

Electromechanical techniques were developed from the 1900s into the 1920s, progressing from the transmission of still photographs to live still duotone images to moving duotone or silhouette images, with each step increasing the sensitivity and speed of the scanning photoelectric cell. John Logie Baird gave the world's first public demonstration of a working television system that transmitted live moving images with tone graduation (grayscale) on January 26, 1926, at his laboratory in London, and built a complete experimental broadcast system around his technology. Baird further demonstrated the world's first color television transmission on July 3, 1928. Other prominent developers of mechanical television included Charles Francis Jenkins, who demonstrated a primitive television system in 1923, Frank Conrad who demonstrated a movie-film-to-television converter at Westinghouse in 1928, and Frank Gray and Herbert E. Ives at Bell Labs who demonstrated wired long-distance television in 1927 and two-way television in 1930.

Color television systems were invented and patented even before black-and-white television was working.

Completely electronic television systems relied on the inventions of Philo Taylor Farnsworth, Vladimir Zworykin and others to produce a system suitable for mass distribution of television programming. Farnsworth gave the world's first public demonstration of an all-electronic television system at the Franklin Institute in Philadelphia on August 25, 1934.

Regular broadcast programming occurred in the United States,[1][2] the United Kingdom,[3] Germany,[4][5] France and the Soviet Union[6][7] before World War II. The first regular television broadcasts with a modern level of definition (240 or more lines) were made in England in 1936, soon upgraded to the so-called "System A" with 405 lines.

Regular network broadcasting began in the United States in 1946, and television became common in American homes by the middle 1950s. While North American over-the-air broadcasting was originally free of direct marginal cost to the consumer (cost in excess of acquisition and upkeep of the hardware) and broadcasters were compensated primarily by receipt of advertising revenue, increasingly United States television consumers obtain their programming by subscription to cable television systems or direct-to-home satellite transmissions. In the United Kingdom, France, and most of the rest of Europe, on the other hand, operators of television equipment must pay an annual license fee, which is usually used to fund (wholly or partly) the appropriate national public service broadcasters (British Broadcasting Corporation, France Télévisions, and so forth).

Technology

Elements of a television system

Digital video equipment in a cutting (editing) room

The elements of a simple television system are:

  • An image source—this may be a camera for live pick-up of images or a flying spot scanner for transmission of films
  • A sound source
  • A transmitter, which modulates one or more television signals with both picture and sound information for transmission
  • A receiver (television) which recovers the picture and sound signals from the television broadcast
  • A display device, which turns the electrical signals into visible light
  • A sound device, which turns electrical signals into sound waves to go along with the picture

Practical television systems include equipment for selecting different image sources, mixing images from several sources at once, insertion of pre-recorded video signals, synchronizing signals from many sources, and direct image generation by computer for such purposes as station identification. Transmission may be over the air from land-based transmitters, over metal or optical cables, or by radio from synchronous satellites. Digital systems may be inserted anywhere in the chain to provide better image transmission quality, reduction in transmission bandwidth, special effects, or security of transmission from reception by non-subscribers.

Display technology

Thanks to advances in display technology, there are now several kinds of video displays used in modern TV sets:

  • CRT (Cathode Ray Tube): The most common screens are direct-view CRTs for up to 40 inches (100 centimeters) (in 4:3) and 46 inches (115 centimeters) (in 16:9) diagonally. These are the least expensive and are a refined technology that can still provide the best value for overall picture quality. As they do not have a fixed native resolution, they are capable of displaying sources with a variety of different resolutions at the best possible image quality. The frame rate or refresh rate of a typical NTSC format CRT TV is 60 Hz, and for the PAL format, is 50 Hz. A typical NTSC broadcast signal's visible portion has an equivalent resolution of about 640 by 480 pixels. It actually could be slightly higher than that, but the Vertical Blanking Interval, or VBI, allows other signals to be carried along with the broadcast.
CeBIT 2006 Philips 3D Display 42 3D6W01 WOW Richardson Electronics KUKFilm 1298 by HDTVTotalDOTcom.jpg
  • Rear projection: Most very large screen TVs (up to over 100 inches (254 cm)) use projection technology. Three types of projection systems are used in projection TVs: CRT-based, LCD-based, and DLP (reflective micromirror chip) -based. Projection television has been commercially available since the 1970s, but at that time could not match the image sharpness of the CRT; current models are vastly improved, and offer a cost-effective large-screen display.
    • A variation is a video projector, using similar technology, which projects onto a screen.
  • Flat panel (LCD or plasma): Modern advances have brought flat panels to TV that use active matrix LCD or plasma display technology. Flat panel LCDs and plasma displays are as little as one inch thick and can be hung on a wall like a picture or put over a pedestal. Some models can also be used as computer monitors.
  • LED technology has become one of the choices for outdoor video and stadium uses, since the advent of ultra high brightness LEDs and driver circuits. LEDs enable scalable ultra-large flat panel video displays that other existing technologies may never be able to match in performance.

Each has its pros and cons. Flat panel LCD displays can have narrow viewing angles and so may not suit a home environment. Rear projection screens do not perform well in natural daylight or well-lit rooms and thus are best suited to dark viewing areas.

Samsung LE26R41BD HDTV.

Terminology for televisions

Pixel resolution is the amount of individual points known as pixels on a given screen. A typical resolution of 720 by 480 means that the television display has 720 pixels across and 480 pixels on the vertical axis. The higher the resolution on a specified display the sharper the image. Contrast ratio is a measurement of the range between the brightest and darkest points on the screen. The higher the contrast ratio, the better looking picture there is in terms of richness, deepness, and shadow detail.

The brightness of a picture measures how vibrant and impacting the colors are. Measured in equivalent to the amount of candles required to power the image.

Transmission band

There are various bands on which televisions operate depending upon the country. The VHF and UHF signals in bands III to V are generally used. Lower frequencies do not have enough bandwidth available for television. Although the BBC initially used Band I VHF at 45 MHz, this frequency is no longer in use for this purpose. Band II is used for FM radio transmissions. Higher frequencies behave more like light and do not penetrate buildings or travel around obstructions well enough to be used in a conventional broadcast TV system, so they are generally only used for satellite broadcasting, which uses frequencies around 10 GHz. TV systems in most countries relay the video as an AM (amplitude-modulation) signal and the sound as a FM (frequency-modulation) signal. An exception is France, where the sound is AM.

Aspect ratios

Aspect ratio refers to the ratio of the horizontal to vertical measurements of a television's picture. Mechanically scanned television as first demonstrated by John Logie Baird in 1926 used a 7:3 vertical aspect ratio, oriented for the head and shoulders of a single person in close-up.

Most of the early electronic TV systems from the mid-1930s onward shared the same aspect ratio of 4:3, which was chosen to match the Academy Ratio used in cinema films at the time. This ratio was also square enough to be conveniently viewed on round cathode-ray tubes (CRTs), which were all that could be produced given the manufacturing technology of the time (today's CRT technology allows the manufacture of much wider tubes, and the flat-screen technologies which are becoming steadily more popular have no technical aspect ratio limitations at all). The BBC's television service used a more squarish 5:4 ratio from 1936 to April 3, 1950, when it too switched to a 4:3 ratio. This did not present significant problems, as most sets at the time used round tubes which were easily adjusted to the 4:3 ratio when the transmissions changed.

In the 1950s, movie studios moved towards widescreen aspect ratios such as CinemaScope in an effort to distance their product from television. Although this was initially just a gimmick, widescreen is still the format of choice today and square aspect ratio movies are rare. Some people argue that widescreen is actually a disadvantage when showing objects that are tall instead of panoramic, others say that natural vision is more panoramic than tall, and therefore widescreen is easier on the eye.

The switch to digital television systems has been used as an opportunity to change the standard television picture format from the old ratio of 4:3 (1.33:1) to an aspect ratio of 16:9 (approximately 1.78:1). This enables TV to get closer to the aspect ratio of modern widescreen movies, which range from 1.66:1 through 1.85:1 to 2.35:1. There are two methods for transporting widescreen content, the better of which uses what is called anamorphic widescreen format. This format is very similar to the technique used to fit a widescreen movie frame inside a 1.33:1 35 millimeter film frame. The image is compressed horizontally when recorded, then expanded again when played back. The anamorphic widescreen 16:9 format was first introduced via European PALPlus television broadcasts and then later on "widescreen" DVDs; the ATSC HDTV system uses straight widescreen format, no horizontal compression or expansion is used.

Widescreen spread from television to computing where both desktop and laptop computers are commonly equipped with widescreen displays. There are some complaints about distortions of movie picture ratio due to some DVD playback software not taking account of aspect ratios, but this may subside as the DVD playback software matures. Furthermore, computer and laptop widescreen displays are in the 16:10 aspect ratio both physically in size and in pixel counts, and not in 16:9 of consumer televisions, leading to further complexity. This was a result of widescreen computer display engineers' uninformed assumption that people viewing 16:9 content on their computer would prefer that an area of the screen be reserved for playback controls, subtitles or their taskbar, as opposed to viewing content full-screen.

Aspect ratio incompatibility

The television industry's changing of aspect ratios is not without difficulties, and can present a considerable problem.

Displaying a widescreen aspect (rectangular) image on a conventional aspect (square or 4:3) display can be shown:

  • in "letterbox" format, with black horizontal bars at the top and bottom
  • with part of the image being cropped, usually the extreme left and right of the image being cut off (or in "pan and scan," parts selected by an operator)
  • with the image horizontally compressed

A conventional aspect (square or 4:3) image on a widescreen aspect (rectangular with longer horizon) display can be shown:

  • in “pillar box" format, with black vertical bars to the left and right
  • with upper and lower portions of the image cut off (or in "tilt and scan," parts selected by an operator)
  • with the image horizontally distorted

A common compromise is to shoot or create material at an aspect ratio of 14:9, and to lose some image at each side for 4:3 presentation, and some image at top and bottom for 16:9 presentation. In recent years, the cinematographic process known as Super 35 (championed by James Cameron) has been used to film a number of major movies such as Titanic, Legally Blonde, Austin Powers, and Crouching Tiger, Hidden Dragon. This process results in a camera-negative which can then be used to create both wide-screen theatrical prints, and standard full screen releases for television/VHS/DVD which avoid the need for either "letterboxing" or the severe loss of information caused by conventional "pan-and-scan" cropping.

Sound

The sound provided by television was originally was similar to monophonic radio. Original televisions that were sold to the public were a small box that showed the image and was attached to a radio. One technique for sound is called a simulcast (simultaneous broadcast) where the sound is broadcast on radio while the video is broadcast on television. Some television stations use FM band to broadcast their sound. With televisions becoming more advanced, it is now quite common to have them with built in stereo. Many televisions today have stereo jacks so people can attach amplifiers to the television for better sound.

Television add-ons

Today there are many television add-ons including video game consoles, VCRs, set-top boxes for cable television, satellite and DVB-T compliant digital television reception, DVD players, or digital video recorders (including personal video recorders, PVRs). The add-on market continues to grow as new technologies are developed.

Exterior designs

In the early days of television, the cabinet was made of wood grain; however, the wood grain began to disappear in the 1980s, being replaced by streamlined plastic exteriors.

Content

Advertising

Since their inception in the U.S. in 1940, TV commercials have become one of the most effective, most pervasive, and most popular methods of selling products of many sorts, especially consumer goods. Advertising rates in the U.S. are determined primarily by Nielsen Ratings.

Programming

Getting TV programming shown to the public can happen in many different ways. After production the next step is to market and deliver the product to whatever markets are open to using it. This typically happens on two levels:

  1. Original Run or First Run—a producer creates a program of one or multiple episodes and shows it on a station or network which has either paid for the production itself or to which a license has been granted by the producers to do the same.
  2. Syndication—this is the terminology rather broadly used to describe secondary programming usages (beyond original run). It includes secondary runs in the country of first issue, but also international usage which may or may not be managed by the originating producer. In many cases other companies, TV stations or individuals are engaged to do the syndication work, in other words to sell the product into the markets they are allowed to sell into by contract from the copyright holders, in most cases the producers.

In most countries, the first wave occurs primarily on free-to-air (FTA) television, while the second wave happens on subscription TV and in other countries. In the U.S., however, the first wave occurs on the FTA networks and subscription services, and the second wave travels via all means of distribution.

First-run programming is increasing on subscription services outside the U.S., but few domestically produced programs are syndicated on domestic FTA elsewhere. This practice is increasing however, generally on digital-only FTA channels, or with subscriber-only first run material appearing on FTA.

Unlike the U.S., repeat FTA screenings of a FTA network program almost only occur on that network. Also, affiliates rarely buy or produce non-network programming that isn't centered around local events.

Social aspects

Almost since the medium's inception there have been charges that some programming is, in one way or another, inappropriate, offensive, or indecent. Critics such as Jean Kilborne have claimed that television, as well as other mass media images, harm the self image of young girls. Other commentators, such as Sut Jhally, make the case that television advertising in the U.S. has been so effective that happiness has increasingly come to be equated with the purchase of products. George Gerbner has presented evidence that the frequent portrayals of crime, especially minority crime, has led to the Mean World Syndrome, the view among frequent viewers of television that crime rates are much higher than the actual data would indicate. In addition, a lot of television has been charged with presenting propaganda, political or otherwise, and being pitched at a low intellectual level. Paralleling television's growing primacy in family life and society, an increasingly vocal chorus of legislators, scientists, and parents is raising objections to the uncritical acceptance of the medium.

Fifty years of research on the impact of television on children's emotional and social development demonstrated that there are clear and lasting effects of viewing violence.[8] In a study published in February 2006,[9] the research team demonstrated that the brain activation patterns of children viewing violence show that children are aroused by the violence (increased heart rates), demonstrate fear (activation of the amygdala, the "fight or flight" sensor in the brain) in response to the video violence, and store the observed violence in an area of the brain (the posterior cingulate) that is reserved for long-term memory of traumatic events.

A 2002 article in Scientific American suggested that compulsive television watching, television addiction, was no different from any other addiction, a finding backed up by reports of withdrawal symptoms among families forced by circumstance to cease watching.[10]

A longitudinal study in New Zealand involving one thousand people (from childhood to 26 years of age) demonstrated that "television viewing in childhood and adolescence is associated with poor educational achievement by 26 years of age." In other words, the more the child watched television, the less likely he or she was to finish school and enroll in a university.

In Iceland, television broadcasting hours were restricted until 1984, with no television programs being broadcast on Thursday, or during the whole of July. Also, the Swedish government imposed a total ban on advertising to children under 12 in 1991.

Despite this research, some media scholars have dismissed the studies as flawed.[11]

Technology trends

In its infancy, television was an ephemeral medium. Fans of regular shows planned their schedules so that they could be available to watch their shows at their time of broadcast. The term “appointment television” was coined by marketers to describe this kind of attachment.

The viewership's dependence on schedule lessened with the invention of programmable video recorders, such as the videocassette recorder and the digital video recorder. Consumers could watch programs on their own schedule once they were broadcast and recorded. Television service providers also offer video on demand, a set of programs which could be watched at any time.

Both mobile phone networks and the Internet are capable of carrying video streams. There is already a fair amount of Internet TV available, either live or as downloadable programs.

See also

Notes

  1. Donna L. Halper, “How Television Came to Boston: The Forgotten Story of W1XAY.” TVhistory.tv. Retrieved May 29, 2007.
  2. H. A. Layer, “Charles Francis Jenkins television station W3XK. Retrieved May 29, 2007.
  3. J. L. Baird: Television in 1934. Bairdtelevision.com. Retrieved May 29, 2007.
  4. Joan Bleicher, Museum of Broadcast Communications: Germany. Retrieved May 29, 2007.
  5. 1936 German (Berlin) Olympics. TVhistory.tv. Retrieved May 29, 2007.
  6. R. W. Burns, Television: An International History of the Formative Years (IET, 1998, ISBN 0852969147), 488.
  7. James O’Neal, RCA's Russian Television Connection. Retrieved May 29, 2007.
  8. Norma Pecora, John P. Murray and Ellen A. Wartella, Children and Television: 50 Years of Research (Lawrence Erlbaum Associates, 2006, ISBN 0805841393).
  9. Media Psychology 8 (1): 25-37.
  10. Robert Kubey and Mihaly Csikszentmihalyi, “Television Addiction is no Mere Metaphor.” Scientific American (February 23, 2002). Retrieved May 29, 2007.
  11. David Gauntlett, “Ten Things Wrong With the Media 'Effects' Model.” University of Westminster. Retrieved May 29, 2007.

References
ISBN links support NWE through referral fees

  • Abramson, Albert. The History of Television, 1942 to 2000. Jefferson, NC: McFarland & Company, 2003. ISBN 0786412208
  • Barnouw, Erik. Tube of Plenty: The Evolution of American Television. New York: Oxford University Press, 1990. ISBN 0195064844
  • Bourdieu, Pierre. On Television. New York: The New Press, 1999. ISBN 1565845129
  • Brooks, Tim, and Earle March. The Complete Guide to Prime Time Network and Cable TV Shows. Ballantine, 2002. ISBN 0345455428
  • Burns, R.W. Television: An International History of the Formative Years. IET, 1998. ISBN 0852969147
  • Debord, Guy. The Society of the Spectacle. Zone Books, 1995. ISBN 0942299795
  • Derrida, Jacques, and Bernard Stiegler. Echographies of Television. Malden, MA: Blackwell Publishers, Inc., 2002. ISBN 074562037X
  • Fisher David E., and Marshall J. Fisher. Tube: the Invention of Television. Washington DC: Counterpoint, 1996. ISBN 1887178171
  • Mander, Jerry. Four Arguments for the Elimination of Television. Reprint edition, 2002. New York: HarperPerennial, 1977. ISBN 0688082742
  • Pecora, Norma, John P. Murray, and Ellen A. Wartella. Children and Television: 50 Years of Research. Lawrence Erlbaum Associates, 2006. ISBN 0805841393
  • Postman, Neil. Amusing Ourselves to Death: Public Discourse in the Age of Show Business. Penguin USA, 1985. ISBN 0670804541
  • Sigman, Aric. Remotely Controlled: How Television Is Damaging Our Lives. Random House UK, 2007. ISBN 0091906903
  • Smith-Shomade, Beretta E. Shaded Lives: African-American Women and Television. Piscataway, NJ: Rutgers University Press, 2002. ISBN 0813531055
  • Taylor, Alan. We, the Media: Pedagogic Intrusion into U.S. Mainstream Film and Television News Broadcasting Rhetorics. Peter Lang Academic Book Publishers, 2005. ISBN 3631518528

External links

All retrieved October 16, 2013.

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