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Television, sometimes shortened to TV, is a telecommunication
medium Medium may refer to: Science and technology Aviation *Medium bomber, a class of war plane *Tecma Medium, a French hang glider design Communication * Media (communication), tools used to store and deliver information or data * Medium of ...
for
transmitting In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to th ...
moving images and sound. The term can refer to a
television set A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube, is a device that combines a tuner, display, and loudspeakers, for the purpose of viewing and hearing television broadcasts, or using ...
, or the medium of television transmission. Television is a
mass medium Mass media refers to a diverse array of media technologies that reach a large audience via mass communication. The technologies through which this communication takes place include a variety of outlets. Broadcast media transmit information ...
for advertising, entertainment, news, and sports. Television became available in crude experimental forms in the late 1920s, but only after several years of further development was the new technology marketed to consumers. After
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
, an improved form of black-and-white television broadcasting became popular in the United Kingdom and the United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing
public opinion Public opinion is the collective opinion on a specific topic or voting intention relevant to a society. It is the people's views on matters affecting them. Etymology The term "public opinion" was derived from the French ', which was first use ...
.Diggs-Brown, Barbara (2011
''Strategic Public Relations: Audience Focused Practice''
p. 48
In the mid-1960s, color broadcasting was introduced in the U.S. and most other developed countries. The availability of various types of archival storage media such as Betamax and VHS tapes, LaserDiscs, high-capacity hard disk drives, CDs,
DVD The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind ...
s,
flash drives A flash drive is a portable computer drive that uses flash memory. Flash drives are the larger memory modules consisting of a number of flash chips. A flash chip is used to read the contents of a single cell, but it can write entire block of cell ...
, high-definition
HD DVD HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the ...
s and Blu-ray Discs, and cloud
digital video recorders A digital video recorder (DVR) is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or networked mass storage device. The term includes set-top boxes with direct to d ...
has enabled viewers to watch pre-recorded material—such as movies—at home on their own time schedule. For many reasons, especially the convenience of remote retrieval, the storage of television and video programming now also occurs on the cloud (such as the video-on-demand service by
Netflix Netflix, Inc. is an American subscription video on-demand over-the-top streaming service and production company based in Los Gatos, California. Founded in 1997 by Reed Hastings and Marc Randolph in Scotts Valley, California, it offers a fi ...
). At the end of the first decade of the 2000s,
digital television Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative adva ...
transmissions greatly increased in popularity. Another development was the move from standard-definition television (SDTV) (
576i 576i is a standard-definition digital video mode, originally used for digitizing analog television in most countries of the world where the utility frequency for electric power distribution is 50 Hz. Because of its close association with ...
, with 576 interlaced lines of resolution and
480i 480i is the video mode used for standard-definition digital television in the Caribbean, Japan, South Korea, Taiwan, Philippines, Laos, Western Sahara, and most of the Americas (with the exception of Argentina, Paraguay, and Uruguay). The ...
) to
high-definition television High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
(HDTV), which provides a resolution that is substantially higher. HDTV may be transmitted in different formats:
1080p 1080p (1920×1080 progressively displayed pixels; also known as Full HD or FHD, and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen ve ...
,
1080i 1080i (also known as Full HD or BT.709) is a combination of frame resolution and scan type. 1080i is used in high-definition television (HDTV) and high-definition video. The number "1080" refers to the number of horizontal lines on the scre ...
and
720p 720p (1280×720 px; also called HD ready, standard HD or just HD) is a progressive HDTV signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcast ...
. Since 2010, with the invention of
smart television A smart TV, also known as a connected TV (CTV), is a traditional television set with integrated Internet and interactive Web 2.0 features, which allows users to stream music and videos, browse the internet, and view photos. Smart TVs are a techno ...
,
Internet television Streaming television is the digital distribution of television content, such as TV shows, as streaming media delivered over the Internet. Streaming television stands in contrast to dedicated terrestrial television delivered by over-the-air a ...
has increased the availability of television programs and movies via the Internet through streaming video services such as Netflix, Amazon Prime Video, iPlayer and Hulu. In 2013, 79% of the world's households owned a television set. The replacement of earlier cathode-ray tube (CRT) screen displays with compact, energy-efficient, flat-panel alternative technologies such as LCDs (both fluorescent-backlit and LED),
OLED An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light i ...
displays, and
plasma display A plasma display panel (PDP) is a type of flat panel display that uses small cells containing plasma: ionized gas that responds to electric fields. Plasma televisions were the first large (over 32 inches diagonal) flat panel displays to be releas ...
s was a hardware revolution that began with computer monitors in the late 1990s. Most television sets sold in the 2000s were flat-panel, mainly LEDs. Major manufacturers announced the discontinuation of CRT,
Digital Light Processing Digital Light Processing (DLP) is a set of chipsets based on optical micro-electro-mechanical technology that uses a digital micromirror device. It was originally developed in 1987 by Larry Hornbeck of Texas Instruments. While the DLP imagin ...
(DLP), plasma, and even fluorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are expected to be gradually replaced by OLEDs. Also, major manufacturers have announced that they will increasingly produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and
Web 2.0 Web 2.0 (also known as participative (or participatory) web and social web) refers to websites that emphasize user-generated content, ease of use, participatory culture and interoperability (i.e., compatibility with other products, systems, and ...
functions became the dominant form of television by the late 2010s. Television signals were initially distributed only as terrestrial television using high-powered
radio-frequency Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upp ...
television transmitter A television transmitter is a transmitter that is used for terrestrial (over-the-air) television broadcasting. It is an electronic device that radiates radio waves that carry a video signal representing moving images, along with a synchronized ...
s to broadcast the signal to individual television receivers. Alternatively television signals are distributed by coaxial cable or optical fiber,
satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioi ...
systems and, since the 2000s via the Internet. Until the early 2000s, these were transmitted as
analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog ...
signals, but a transition to digital television was expected to be completed worldwide by the late 2010s. A standard television set consists of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is correctly called a
video monitor A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...
rather than a television.


Etymology

The word ''television'' comes . The first documented usage of the term dates back to 1900, when the Russian scientist Constantin Perskyi used it in a paper that he presented in French at the first International Congress of Electricity, which ran from 18 to 25 August 1900 during the International World Fair in Paris. The anglicised version of the term is first attested in 1907, when it was still "...a theoretical system to transmit moving images over
telegraph Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas p ...
or telephone wires". It was "...formed in English or borrowed from French ." In the 19th century and early 20th century, other "...proposals for the name of a then-hypothetical technology for sending pictures over distance were telephote (1880) and televista (1904)." The abbreviation ''TV'' is from 1948. The use of the term to mean "a
television set A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube, is a device that combines a tuner, display, and loudspeakers, for the purpose of viewing and hearing television broadcasts, or using ...
" dates from 1941. The use of the term to mean "television as a medium" dates from 1927. The slang term ''telly'' is more common in the UK. The slang term "the tube" or the "boob tube" derives from the bulky cathode-ray tube used on most TVs until the advent of flat-screen TVs. Another slang term for the TV is "idiot box". Also, in the 1940s and throughout the 1950s, during the early rapid growth of television programming and television set ownership in the United States, another slang term became widely used in that period and continues to be used today to distinguish productions originally created for broadcast on television from films developed for presentation in movie theaters.Johnson, Richard (2018)
“Big movie stars are not making the cut on the small screen”
p. 6, ''
The New York Post The ''New York Post'' (''NY Post'') is a conservative daily tabloid newspaper published in New York City. The ''Post'' also operates NYPost.com, the celebrity gossip site PageSix.com, and the entertainment site Decider.com. It was established ...
'', 11 October 2018. Retrieved 24 November 2018.
The "small screen", as both a compound adjective and noun, became specific references to television, while the " big screen" was used to identify productions made for theatrical release.


History


Mechanical

Facsimile transmission Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...
systems for still photographs pioneered methods of mechanical scanning of images in the early 19th century. Alexander Bain introduced the facsimile machine between 1843 and 1846. Frederick Bakewell demonstrated a working laboratory version in 1851. Willoughby Smith discovered the
photoconductivity Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation ...
of the element
selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
in 1873. As a 23-year-old German university student, Paul Julius Gottlieb Nipkow proposed and patented the
Nipkow disk A Nipkow disk (sometimes Anglicized as Nipkov disk; patented in 1884), also known as scanning disk, is a mechanical, rotating, geometrically operating image scanning device, patented in 1885 by Paul Gottlieb Nipkow. This scanning disk was a funda ...
in 1884. This was a spinning disk with a spiral pattern of holes in it, so each hole scanned a line of the image. Although he never built a working model of the system, variations of Nipkow's spinning-disk " image rasterizer" became exceedingly common. Constantin Perskyi had coined the word ''television'' in a paper read to the International Electricity Congress at the International World Fair in Paris on 24 August 1900. Perskyi's paper reviewed the existing electromechanical technologies, mentioning the work of Nipkow and others. However, it was not until 1907 that developments in amplification tube technology by Lee de Forest and Arthur Korn, among others, made the design practical."Sending Photographs by Telegraph"
''The New York Times'', Sunday Magazine, 20 September 1907, p. 7.
The first demonstration of the live transmission of images was by Georges Rignoux and A. Fournier in Paris in 1909. A matrix of 64
selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
cells, individually wired to a mechanical commutator, served as an electronic
retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
. In the receiver, a type of Kerr cell modulated the light and a series of differently angled mirrors attached to the edge of a rotating disc scanned the modulated beam onto the display screen. A separate circuit regulated synchronization. The 8x8
pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the ...
resolution in this proof-of-concept demonstration was just sufficient to clearly transmit individual letters of the alphabet. An updated image was transmitted "several times" each second. In 1911, Boris Rosing and his student Vladimir Zworykin created a system that used a mechanical mirror-drum scanner to transmit, in Zworykin's words, "very crude images" over wires to the " Braun tube" ( cathode-ray tube or "CRT") in the receiver. Moving images were not possible because, in the scanner: "the sensitivity was not enough and the selenium cell was very laggy". In 1921, Edouard Belin sent the first image via radio waves with his belinograph. By the 1920s, when amplification made television practical, Scottish inventor
John Logie Baird John Logie Baird FRSE (; 13 August 188814 June 1946) was a Scottish inventor, electrical engineer, and innovator who demonstrated the world's first live working television system on 26 January 1926. He went on to invent the first publicly dem ...
employed the Nipkow disk in his prototype video systems. On 25 March 1925, Baird gave the first public demonstration of televised
silhouette A silhouette ( , ) is the image of a person, animal, object or scene represented as a solid shape of a single colour, usually black, with its edges matching the outline of the subject. The interior of a silhouette is featureless, and the silhou ...
images in motion, at
Selfridges Selfridges, also known as Selfridges & Co., is a chain of high-end department stores in the United Kingdom that is operated by Selfridges Retail Limited, part of the Selfridges Group of department stores. It was founded by Harry Gordon Selfridg ...
's department store in London. Since human faces had inadequate contrast to show up on his primitive system, he televised a ventriloquist's dummy named "Stooky Bill", whose painted face had higher contrast, talking and moving. By 26 January 1926, he had demonstrated the transmission of an image of a face in motion by radio. This is widely regarded as the world's first public television demonstration. Baird's system used the Nipkow disk for both scanning the image and displaying it. A brightly illuminated subject was placed in front of a spinning Nipkow disk set with lenses which swept images across a static photocell. The thallium sulphide (Thalofide) cell, developed by
Theodore Case Theodore Willard Case (December 12, 1888 – May 13, 1944) was an American chemist and inventor known for the invention of the Movietone sound-on-film system. Early life and education Theodore Willard Case was born in 1888 in Auburn, New Yo ...
in the U.S., detected the light reflected from the subject and converted it into a proportional electrical signal. This was transmitted by AM radio waves to a receiver unit, where the video signal was applied to a neon light behind a second Nipkow disk rotating synchronized with the first. The brightness of the neon lamp was varied in proportion to the brightness of each spot on the image. As each hole in the disk passed by, one
scan line A scan line (also scanline) is one line, or row, in a raster scanning pattern, such as a line of video on a cathode ray tube (CRT) display of a television set or computer monitor. On CRT screens the horizontal scan lines are visually discernible ...
of the image was reproduced. Baird's disk had 30 holes, producing an image with only 30 scan lines, just enough to recognize a human face. In 1927, Baird transmitted a signal over of telephone line between London and
Glasgow Glasgow ( ; sco, Glesca or ; gd, Glaschu ) is the most populous city in Scotland and the fourth-most populous city in the United Kingdom, as well as being the 27th largest city by population in Europe. In 2020, it had an estimated popul ...
. In 1928, Baird's company (Baird Television Development Company/Cinema Television) broadcast the first transatlantic television signal, between London and New York, and the first shore-to-ship transmission. In 1929, he became involved in the first experimental mechanical television service in Germany. In November of the same year, Baird and Bernard Natan of Pathé established France's first television company, Télévision- Baird-Natan. In 1931, he made the first outdoor remote broadcast, of The Derby. In 1932, he demonstrated ultra-short wave television. Baird's mechanical system reached a peak of 240-lines of resolution on
BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
telecasts in 1936, though the mechanical system did not scan the televised scene directly. Instead a 17.5 mm film was shot, rapidly developed and then scanned while the film was still wet. A U.S. inventor, Charles Francis Jenkins, also pioneered the television. He published an article on "Motion Pictures by Wireless" in 1913; transmitted moving silhouette images for witnesses in December 1923; and on 13 June 1925 publicly demonstrated synchronized transmission of silhouette pictures. In 1925 Jenkins used the Nipkow disk and transmitted the silhouette image of a toy windmill in motion, over a distance of 5 miles (8 km), from a naval radio station in Maryland to his laboratory in Washington, D.C., using a lensed disk scanner with a 48-line resolution. He was granted U.S. Patent No. 1,544,156 (Transmitting Pictures over Wireless) on 30 June 1925 (filed 13 March 1922).
Herbert E. Ives Herbert Eugene Ives (July 31, 1882 – November 13, 1953) was a scientist and engineer who headed the development of facsimile and television systems at AT&T in the first half of the twentieth century. He is best known for the 1938 Ives–Stilwel ...
and
Frank Gray Francis Tierney Gray (born 27 October 1954) is a Scottish football manager and former player. He played for Leeds United, Nottingham Forest, Sunderland and Darlington, while he also represented Scotland 32 times. Gray has managed Darlington, ...
of
Bell Telephone Laboratories Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...
gave a dramatic demonstration of mechanical television on 7 April 1927. Their reflected-light television system included both small and large viewing screens. The small receiver had a 2-inch-wide by 2.5-inch-high screen (5 by 6 cm). The large receiver had a screen 24 inches wide by 30 inches high (60 by 75 cm). Both sets could reproduce reasonably accurate, monochromatic, moving images. Along with the pictures, the sets received synchronized sound. The system transmitted images over two paths: first, a
copper wire Copper has been used in electrical wiring since the invention of the electromagnet and the telegraph in the 1820s. The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor. Copper is the electri ...
link from Washington to New York City, then a radio link from
Whippany, New Jersey Whippany is a Local government in New Jersey#Unincorporated communities, unincorporated community located within Hanover Township, New Jersey, Hanover Township in Morris County, New Jersey, Morris County, New Jersey, United States. Whippany's na ...
. Comparing the two transmission methods, viewers noted no difference in quality. Subjects of the telecast included Secretary of Commerce
Herbert Hoover Herbert Clark Hoover (August 10, 1874 – October 20, 1964) was an American politician who served as the 31st president of the United States from 1929 to 1933 and a member of the Republican Party, holding office during the onset of the Gr ...
. A
flying-spot scanner A flying-spot scanner (FSS) uses a scanning source of a spot of light, such as a high-resolution, high-light-output, low-persistence cathode ray tube (CRT), to scan an image. Usually the image to be scanned is on photographic film, such as motion ...
beam illuminated these subjects. The scanner that produced the beam had a 50-aperture disk. The disc revolved at a rate of 18 frames per second, capturing one frame about every 56 milliseconds. (Today's systems typically transmit 30 or 60 frames per second, or one frame every 33.3 or 16.7 milliseconds respectively.) Television historian Albert Abramson underscored the significance of the Bell Labs demonstration: "It was in fact the best demonstration of a mechanical television system ever made to this time. It would be several years before any other system could even begin to compare with it in picture quality." In 1928,
WRGB WRGB (channel 6) is a television station licensed to Schenectady, New York, United States, serving the Capital District as an affiliate of CBS. It is owned by Sinclair Broadcast Group alongside CW affiliate WCWN (channel 45, also licensed to Sc ...
, then W2XB, was started as the world's first television station. It broadcast from the
General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable en ...
facility in
Schenectady, NY Schenectady () is a city in Schenectady County, New York, United States, of which it is the county seat. As of the 2020 census, the city's population of 67,047 made it the state's ninth-largest city by population. The city is in eastern New Y ...
. It was popularly known as " WGY Television". Meanwhile, in the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
,
Léon Theremin Leon Theremin (born Lev Sergeyevich Termen rus, Лев Сергеевич Термéн, p=ˈlʲef sʲɪrˈɡʲejɪvʲɪtɕ tɨrˈmʲen; – 3 November 1993) was a Russian and Soviet inventor, most famous for his invention of the theremin, one o ...
had been developing a mirror drum-based television, starting with 16 lines resolution in 1925, then 32 lines and eventually 64 using interlacing in 1926. As part of his thesis, on 7 May 1926, he electrically transmitted, and then projected, near-simultaneous moving images on a screen. By 1927 Theremin had achieved an image of 100 lines, a resolution that was not surpassed until May 1932 by RCA, with 120 lines. On 25 December 1926
Kenjiro Takayanagi was a Japanese engineer and a pioneer in the development of television. Although he failed to gain much recognition in the West, he built the world's first all-electronic television receiver, and is referred to as "the father of Japanese televisi ...
demonstrated a television system with 40-line resolution that employed a Nipkow disk scanner and CRT display at Hamamatsu Industrial High School in Japan. This prototype is still on display at the Takayanagi Memorial Museum in
Shizuoka University is a List of national universities in Japan, national university in Shizuoka Prefecture, Japan. Shizuoka University is well known in the field of engineering, in creative innovation, and in the invention of next generation technology, with ...
, Hamamatsu Campus. His research in creating a production model was halted by the SCAP after
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
.''Kenjiro Takayanagi: The Father of Japanese Television''
, NHK (Japan Broadcasting Corporation), 2002. Retrieved 23 May 2009.
Because only a limited number of holes could be made in the disks, and disks beyond a certain diameter became impractical, image resolution on mechanical television broadcasts was relatively low, ranging from about 30 lines up to 120 or so. Nevertheless, the image quality of 30-line transmissions steadily improved with technical advances, and by 1933 the UK broadcasts using the Baird system were remarkably clear. A few systems ranging into the 200-line region also went on the air. Two of these were the 180-line system that Compagnie des Compteurs (CDC) installed in Paris in 1935, and the 180-line system that Peck Television Corp. started in 1935 at station VE9AK in
Montreal Montreal ( ; officially Montréal, ) is the second-most populous city in Canada and most populous city in the Canadian province of Quebec. Founded in 1642 as '' Ville-Marie'', or "City of Mary", it is named after Mount Royal, the triple ...
. The advancement of all-electronic television (including image dissectors and other camera tubes and cathode-ray tubes for the reproducer) marked the start of the end for mechanical systems as the dominant form of television. Mechanical television, despite its inferior image quality and generally smaller picture, would remain the primary television technology until the 1930s. The last mechanical telecasts ended in 1939 at stations run by a lot of public universities in the United States.


Electronic

In 1897, English
physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...
J. J. Thomson Sir Joseph John Thomson (18 December 1856 – 30 August 1940) was a British physicist and Nobel Laureate in Physics, credited with the discovery of the electron, the first subatomic particle to be discovered. In 1897, Thomson showed that ...
was able, in his three well-known experiments, to deflect cathode rays, a fundamental function of the modern cathode-ray tube (CRT). The earliest version of the CRT was invented by the German physicist
Ferdinand Braun Karl Ferdinand Braun (; 6 June 1850 – 20 April 1918) was a German electrical engineer, inventor, physicist and Nobel laureate in physics. Braun contributed significantly to the development of radio and television technology: he shared the ...
in 1897 and is also known as the "Braun" tube. It was a
cold-cathode A cold cathode is a cathode that is not electrically heated by a filament.A negatively charged electrode emits electrons or is the positively charged terminal. For more, see field emission. A cathode may be considered "cold" if it emits more ele ...
diode, a modification of the
Crookes tube A Crookes tube (also Crookes–Hittorf tube) is an early experimental electrical discharge tube, with partial vacuum, invented by English physicist William Crookes and others around 1869-1875, in which cathode rays, streams of electrons, were ...
, with a phosphor-coated screen. Braun was the first to conceive the use of a CRT as a display device. In 1906 the Germans Max Dieckmann and Gustav Glage produced
raster images upright=1, The Smiley, smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for ...
for the first time in a CRT. In 1907, Russian scientist Boris Rosing used a CRT in the receiving end of an experimental
video signal Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) sy ...
to form a picture. He managed to display simple geometric shapes onto the screen. In 1908,
Alan Archibald Campbell-Swinton Alan Archibald Campbell-Swinton FRS (18 October 1863 – 19 February 1930) was a Scottish consulting electrical engineer, who provided the theoretical basis for the electronic television, two decades before the technology existed to implement ...
, fellow of the
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
(UK), published a letter in the scientific journal ''
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
'' in which he described how "distant electric vision" could be achieved by using a cathode-ray tube, or Braun tube, as both a transmitting and receiving device, He expanded on his vision in a speech given in London in 1911 and reported in ''
The Times ''The Times'' is a British daily national newspaper based in London. It began in 1785 under the title ''The Daily Universal Register'', adopting its current name on 1 January 1788. ''The Times'' and its sister paper '' The Sunday Times'' (f ...
'' and the Journal of the Röntgen Society. Shiers, George and May (1997), ''Early television: a bibliographic guide to 1940''
New York: Garland, p. 56. Retrieved 13 June 2010.
In a letter to ''
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
'' published in October 1926, Campbell-Swinton also announced the results of some "not very successful experiments" he had conducted with G. M. Minchin and J. C. M. Stanton. They had attempted to generate an electrical signal by projecting an image onto a selenium-coated metal plate that was simultaneously scanned by a
cathode ray Cathode rays or electron beam (e-beam) are streams of electrons observed in discharge tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow, due to el ...
beam. These experiments were conducted before March 1914, when Minchin died, but they were later repeated by two different teams in 1937, by H. Miller and J. W. Strange from
EMI EMI Group Limited (originally an initialism for Electric and Musical Industries, also referred to as EMI Records Ltd. or simply EMI) was a British Transnational corporation, transnational Conglomerate (company), conglomerate founded in March 1 ...
, and by H. Iams and A. Rose from
RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
. Both teams succeeded in transmitting "very faint" images with the original Campbell-Swinton's selenium-coated plate. Although others had experimented with using a cathode-ray tube as a receiver, the concept of using one as a transmitter was novel. The first cathode-ray tube to use a
hot cathode In vacuum tubes and gas-filled tubes, a hot cathode or thermionic cathode is a cathode electrode which is heated to make it emit electrons due to thermionic emission. This is in contrast to a cold cathode, which does not have a heating elemen ...
was developed by John B. Johnson (who gave his name to the term Johnson noise) and Harry Weiner Weinhart of Western Electric, and became a commercial product in 1922. In 1926, Hungarian engineer
Kálmán Tihanyi Kálmán Tihanyi or in English language technical literature often mentioned as Coloman Tihanyi or Koloman Tihanyi (28 April 1897 – 26 February 1947) was a Hungarian physicist, electrical engineer and inventor. One of the early pioneers ...
designed a television system using fully electronic scanning and display elements and employing the principle of "charge storage" within the scanning (or "camera") tube.United States Patent Office, Patent No. 2,133,123, 11 October 1938.United States Patent Office, Patent No. 2,158,259, 16 May 1939 The problem of low sensitivity to light resulting in low electrical output from transmitting or "camera" tubes would be solved with the introduction of charge-storage technology by Kálmán Tihanyi beginning in 1924.
"Kálmán Tihanyi (1897–1947)", ''IEC Techline'', International Electrotechnical Commission (IEC), 15 July 2009.
His solution was a camera tube that accumulated and stored electrical charges ("photoelectrons") within the tube throughout each scanning cycle. The device was first described in a patent application he filed in
Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the ...
in March 1926 for a television system he called "Radioskop"."Kálmán Tihanyi's 1926 Patent Application 'Radioskop'"
''Memory of the World'', United Nations Educational, Scientific and Cultural Organization (
UNESCO The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It ...
), 2005. Retrieved 29 January 2009.
After further refinements included in a 1928 patent application, Tihanyi's patent was declared void in Great Britain in 1930,Tihanyi, Koloman, ''Improvements in television apparatus''
European Patent Office, Patent No. GB313456. Convention date UK application: 1928-06-11, declared void and published: 11 November 1930. Retrieved 25 April 2013.
so he applied for patents in the United States. Although his breakthrough would be incorporated into the design of
RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
's " iconoscope" in 1931, the U.S. patent for Tihanyi's transmitting tube would not be granted until May 1939. The patent for his receiving tube had been granted the previous October. Both patents had been purchased by RCA prior to their approval. Charge storage remains a basic principle in the design of imaging devices for television to the present day. On 25 December 1926, at Hamamatsu Industrial High School in Japan, Japanese inventor
Kenjiro Takayanagi was a Japanese engineer and a pioneer in the development of television. Although he failed to gain much recognition in the West, he built the world's first all-electronic television receiver, and is referred to as "the father of Japanese televisi ...
demonstrated a TV system with a 40-line resolution that employed a CRT display. This was the first working example of a fully electronic television receiver. Takayanagi did not apply for a patent. In the 1930s,
Allen B. DuMont Allen Balcom DuMont, also spelled Du Mont, (January 29, 1901 – November 14, 1965) was an American electronics engineer, scientist and invention, inventor best known for improvements to the cathode ray tube in 1931 for use in television receive ...
made the first CRTs to last 1,000 hours of use, which was one of the factors that led to the widespread adoption of television. On 7 September 1927, U.S. inventor
Philo Farnsworth Philo Taylor Farnsworth (August 19, 1906 – March 11, 1971) was an American inventor and television pioneer. He made many crucial contributions to the early development of all-electronic television. He is best known for his 1927 invention of t ...
's
image dissector An image dissector, also called a dissector tube, is a video camera tube in which photocathode emissions create an "electron image" which is then swept up, down and across an anode to produce an electrical signal representing the visual image. It e ...
camera tube transmitted its first image, a simple straight line, at his laboratory at 202 Green Street in San Francisco.Postman, Neil, "Philo Farnsworth"
''The TIME 100: Scientists & Thinkers'', ''Time'', 29 March 1999. Retrieved 28 July 2009.

, ''The Virtual Museum of the City of San Francisco''. Retrieved 15 July 2009.
By 3 September 1928, Farnsworth had developed the system sufficiently to hold a demonstration for the press. This is widely regarded as the first electronic television demonstration. In 1929, the system was improved further by the elimination of a motor generator, so that his television system now had no mechanical parts. That year, Farnsworth transmitted the first live human images with his system, including a three and a half-inch image of his wife Elma ("Pem") with her eyes closed (possibly due to the bright lighting required). Meanwhile, Vladimir Zworykin was also experimenting with the cathode-ray tube to create and show images. While working for
Westinghouse Electric The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in ...
in 1923, he began to develop an electronic camera tube. But in a 1925 demonstration, the image was dim, had low contrast, and poor definition, and was stationary. Zworykin's imaging tube never got beyond the laboratory stage. But RCA, which acquired the Westinghouse patent, asserted that the patent for Farnsworth's 1927 image dissector was written so broadly that it would exclude any other electronic imaging device. Thus RCA, on the basis of Zworykin's 1923 patent application, filed a patent interference suit against Farnsworth. The U.S. Patent Office examiner disagreed in a 1935 decision, finding priority of invention for Farnsworth against Zworykin. Farnsworth claimed that Zworykin's 1923 system would be unable to produce an electrical image of the type to challenge his patent. Zworykin received a patent in 1928 for a color transmission version of his 1923 patent application;Zworykin, Vladimir K., Television System
. Patent No. 1691324, U.S. Patent Office. Filed 1925-07-13, issued 13 November 1928. Retrieved 28 July 2009
he also divided his original application in 1931.Zworykin, Vladimir K., Television System
. Patent No. 2022450, U.S. Patent Office. Filed 1923-12-29, issued 26 November 1935. Retrieved 10 May 2010.
Zworykin was unable or unwilling to introduce evidence of a working model of his tube that was based on his 1923 patent application. In September 1939, after losing an appeal in the courts, and determined to go forward with the commercial manufacturing of television equipment, RCA agreed to pay Farnsworth US$1 million over a ten-year period, in addition to license payments, to use his patents.Everson, George (1949), ''The Story of Television, The Life of Philo T. Farnsworth'' New York: W.W. Norton & Co,. , 266 pp. In 1933, RCA introduced an improved camera tube that relied on Tihanyi's charge storage principle. Called the "Iconoscope" by Zworykin, the new tube had a light sensitivity of about 75,000 lux, and thus was claimed to be much more sensitive than Farnsworth's image dissector. However, Farnsworth had overcome his power issues with his Image Dissector through the invention of a completely unique "multipactor" device that he began work on in 1930, and demonstrated in 1931.Abramson, Albert (1987), ''The History of Television, 1880 to 1941''. Jefferson, NC: Albert Abramson. p. 148. .Everson, George (1949), ''The Story of Television, The Life of Philo T. Farnsworth'' New York: W.W. Norton & Co,. , pp. 137–141. This small tube could amplify a signal reportedly to the 60th power or betterEverson, George (1949), ''The Story of Television, The Life of Philo T. Farnsworth'' New York: W.W. Norton & Co,. , p. 139. and showed great promise in all fields of electronics. Unfortunately, an issue with the multipactor was that it wore out at an unsatisfactory rate.Everson, George (1949), ''The Story of Television, The Life of Philo T. Farnsworth'' New York: W.W. Norton & Co,. , p. 141. At the
Berlin Radio Show The IFA ( ) or Internationale Funkausstellung Berlin (International radio exhibition Berlin, a.k.a. 'Berlin Radio Show') is one of the oldest industrial exhibitions in Germany. Between 1924 and 1939 it was an annual event, but from 1950 it was ...
in August 1931,
Manfred von Ardenne Manfred von Ardenne (20 January 1907 – 26 May 1997) was a German researcher and applied physicist and inventor. He took out approximately 600 patents in fields including electron microscopy, medical technology, nuclear technology, plasma physics ...
gave a public demonstration of a television system using a CRT for both transmission and reception. However, Ardenne had not developed a camera tube, using the CRT instead as a
flying-spot scanner A flying-spot scanner (FSS) uses a scanning source of a spot of light, such as a high-resolution, high-light-output, low-persistence cathode ray tube (CRT), to scan an image. Usually the image to be scanned is on photographic film, such as motion ...
to scan slides and film. Philo Farnsworth gave the world's first public demonstration of an all-electronic television system, using a live camera, at the
Franklin Institute The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memori ...
of
Philadelphia Philadelphia, often called Philly, is the List of municipalities in Pennsylvania#Municipalities, largest city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, the List of United States cities by population, sixth-largest city i ...
on 25 August 1934, and for ten days afterwards.Burns, R.W. ''Television: An international history of the formative years''. (1998). IEE History of Technology Series, 22. London: IEE, p. 370. . Mexican inventor
Guillermo González Camarena Guillermo González Camarena (17 February 1917 – 18 April 1965) was a Mexican electrical engineer who was the inventor of a color-wheel type of color television. Early life González Camarena was born in Guadalajara, Mexico. He was the younge ...
also played an important role in early television. His experiments with television (known as telectroescopía at first) began in 1931 and led to a patent for the "trichromatic field sequential system" color television in 1940. In Britain, the
EMI EMI Group Limited (originally an initialism for Electric and Musical Industries, also referred to as EMI Records Ltd. or simply EMI) was a British Transnational corporation, transnational Conglomerate (company), conglomerate founded in March 1 ...
engineering team led by Isaac Shoenberg applied in 1932 for a patent for a new device they called "the Emitron", which formed the heart of the cameras they designed for the BBC. On 2 November 1936, a 405-line broadcasting service employing the Emitron began at studios in Alexandra Palace, and transmitted from a specially built mast atop one of the Victorian building's towers. It alternated for a short time with Baird's mechanical system in adjoining studios, but was more reliable and visibly superior. This was the world's first regular "high-definition" television service.Burns, R.W., ''Television: An international history of the formative years''. (1998). IEE History of Technology Series, 22. London: IEE, p. 576. . The original U.S. iconoscope was noisy, had a high ratio of interference to signal, and ultimately gave disappointing results, especially when compared to the high definition mechanical scanning systems then becoming available. The
EMI EMI Group Limited (originally an initialism for Electric and Musical Industries, also referred to as EMI Records Ltd. or simply EMI) was a British Transnational corporation, transnational Conglomerate (company), conglomerate founded in March 1 ...
team, under the supervision of Isaac Shoenberg, analyzed how the iconoscope (or Emitron) produces an electronic signal and concluded that its real efficiency was only about 5% of the theoretical maximum. They solved this problem by developing, and patenting in 1934, two new camera tubes dubbed super-Emitron and CPS Emitron. The super-Emitron was between ten and fifteen times more sensitive than the original Emitron and iconoscope tubes and, in some cases, this ratio was considerably greater. It was used for
outside broadcasting Outside broadcasting (OB) is the electronic field production (EFP) of television or radio programmes (typically to cover television news and sports television events) from a mobile remote broadcast television studio. Professional video camera ...
by the BBC, for the first time, on
Armistice Day Armistice Day, later known as Remembrance Day in the Commonwealth and Veterans Day in the United States, is commemorated every year on 11 November to mark the armistice signed between the Allies of World War I and Germany at Compiègne, Fran ...
1937, when the general public could watch on a television set as the King laid a wreath at the Cenotaph. This was the first time that anyone had broadcast a live street scene from cameras installed on the roof of neighboring buildings, because neither Farnsworth nor RCA would do the same until the 1939 New York World's Fair. On the other hand, in 1934, Zworykin shared some patent rights with the German licensee company Telefunken. The "image iconoscope" ("Superikonoskop" in Germany) was produced as a result of the collaboration. This tube is essentially identical to the super-Emitron. The production and commercialization of the super-Emitron and image iconoscope in Europe were not affected by the patent war between Zworykin and Farnsworth, because Dieckmann and Hell had priority in Germany for the invention of the image dissector, having submitted a patent application for their ''Lichtelektrische Bildzerlegerröhre für Fernseher'' (''Photoelectric Image Dissector Tube for Television'') in Germany in 1925, two years before Farnsworth did the same in the United States. The image iconoscope (Superikonoskop) became the industrial standard for public broadcasting in Europe from 1936 until 1960, when it was replaced by the vidicon and plumbicon tubes. Indeed, it was the representative of the European tradition in electronic tubes competing against the American tradition represented by the image orthicon. The German company Heimann produced the Superikonoskop for the 1936 Berlin Olympic Games, later Heimann also produced and commercialized it from 1940 to 1955; finally the Dutch company
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
produced and commercialized the image iconoscope and multicon from 1952 to 1958. U.S. television broadcasting, at the time, consisted of a variety of markets in a wide range of sizes, each competing for programming and dominance with separate technology, until deals were made and standards agreed upon in 1941.Everson, George (1949), ''The Story of Television, The Life of Philo T. Farnsworth'' New York: W.W. Norton & Co,. , p. 248. RCA, for example, used only Iconoscopes in the New York area, but Farnsworth Image Dissectors in Philadelphia and San Francisco.Abramson, Albert (1987), ''The History of Television, 1880 to 1941''. Jefferson, NC: Albert Abramson. p. 254. . In September 1939, RCA agreed to pay the Farnsworth Television and Radio Corporation royalties over the next ten years for access to Farnsworth's patents.Schatzkin, Paul (2002), ''The Boy Who Invented Television''. Silver Spring, Maryland: Teamcom Books, pp. 187–88. . With this historic agreement in place, RCA integrated much of what was best about the Farnsworth Technology into their systems. In 1941, the United States implemented 525-line television. Electrical engineer
Benjamin Adler Benjamin Adler (10 November 1903 – 16 April 1990) was an American electrical engineer and inventor who helped develop the first commercial television set. He was born in New York City to Romanian Jewish immigrants. He graduated from the-now New ...
played a prominent role in the development of television. The world's first 625-line television standard was designed in the Soviet Union in 1944 and became a national standard in 1946."On the beginning of broadcast in 625 lines 60 years ago"
''625'' magazine (in Russian).
The first broadcast in 625-line standard occurred in Moscow in 1948. The concept of 625 lines per frame was subsequently implemented in the European CCIR standard. In 1936,
Kálmán Tihanyi Kálmán Tihanyi or in English language technical literature often mentioned as Coloman Tihanyi or Koloman Tihanyi (28 April 1897 – 26 February 1947) was a Hungarian physicist, electrical engineer and inventor. One of the early pioneers ...
described the principle of
plasma display A plasma display panel (PDP) is a type of flat panel display that uses small cells containing plasma: ionized gas that responds to electric fields. Plasma televisions were the first large (over 32 inches diagonal) flat panel displays to be releas ...
, the first
flat panel display A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment. Flat-panel displays are thin, lightweight, provide better l ...
system. Early electronic
television sets A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube, is a device that combines a tuner, display, and loudspeakers, for the purpose of viewing and hearing television broadcasts, or using ...
were large and bulky, with analog circuits made of
vacuum tubes A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a ...
. Following the invention of the first working
transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...
at
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial Research and development, research and scientific developm ...
,
Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professiona ...
founder
Masaru Ibuka Masaru Ibuka (井深 大 ''Ibuka Masaru''; April 11, 1908 – December 19, 1997) was a Japanese electronics industrialist and co-founder of Sony, along with Akio Morita.Kirkup, James"Obituary: Masaru Ibuka,"''Independent'' (London). December 2 ...
predicted in 1952 that the transition to
electronic circuits An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. It is a type of electrical ...
made of transistors would lead to smaller and more portable television sets. The first fully transistorized, portable solid-state television set was the 8-inch Sony TV8-301, developed in 1959 and released in 1960. This began the transformation of television viewership from a communal viewing experience to a solitary viewing experience. By 1960, Sony had sold over 4million portable television sets worldwide.


Color

The basic idea of using three monochrome images to produce a color image had been experimented with almost as soon as black-and-white televisions had first been built. Although he gave no practical details, among the earliest published proposals for television was one by Maurice Le Blanc, in 1880, for a color system, including the first mentions in television literature of line and frame scanning. Polish inventor
Jan Szczepanik Jan Szczepanik (June 13, 1872 – April 18, 1926) was a Polish inventor, with several hundred patents and over 50 discoveries to his name, many of which are still applied today, especially in the motion picture industry, as well as in photography ...
patented a color television system in 1897, using a
selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
photoelectric cell at the transmitter and an electromagnet controlling an oscillating mirror and a moving prism at the receiver. But his system contained no means of analyzing the spectrum of colors at the transmitting end, and could not have worked as he described it. Another inventor,
Hovannes Adamian Hovhannes (Ivan) Abgari Adamian (5 February 1879 – 12 September 1932) was an Armenian engineer, an author of more than 20 inventions. The first experimental color television was shown in London in 1928 based on Adamian's tricolor principle, and h ...
, also experimented with color television as early as 1907. The first color television project is claimed by him, and was patented in Germany on 31 March 1908, patent No. 197183, then in Britain, on 1 April 1908, patent No. 7219, in France (patent No. 390326) and in Russia in 1910 (patent No. 17912).A. Rokhlin, Tak rozhdalos' dal'novidenie (in Russian)
Scottish inventor
John Logie Baird John Logie Baird FRSE (; 13 August 188814 June 1946) was a Scottish inventor, electrical engineer, and innovator who demonstrated the world's first live working television system on 26 January 1926. He went on to invent the first publicly dem ...
demonstrated the world's first color transmission on 3 July 1928, using scanning discs at the transmitting and receiving ends with three spirals of apertures, each spiral with filters of a different primary color; and three light sources at the receiving end, with a commutator to alternate their illumination. Baird also made the world's first color broadcast on 4 February 1938, sending a mechanically scanned 120-line image from Baird's
Crystal Palace Crystal Palace may refer to: Places Canada * Crystal Palace Complex (Dieppe), a former amusement park now a shopping complex in Dieppe, New Brunswick * Crystal Palace Barracks, London, Ontario * Crystal Palace (Montreal), an exhibition building ...
studios to a projection screen at London's
Dominion Theatre The Dominion Theatre is a West End theatre and former cinema on Tottenham Court Road, close to St Giles Circus and Centre Point, in the London Borough of Camden. Planned as primarily a musical theatre, it opened in 1929, but the following year ...
. Mechanically scanned color television was also demonstrated by
Bell Laboratories Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...
in June 1929 using three complete systems of photoelectric cells, amplifiers, glow-tubes, and color filters, with a series of mirrors to superimpose the red, green, and blue images into one full color image. The first practical hybrid system was again pioneered by John Logie Baird. In 1940 he publicly demonstrated a color television combining a traditional black-and-white display with a rotating colored disk. This device was very "deep", but was later improved with a mirror folding the light path into an entirely practical device resembling a large conventional console. However, Baird was unhappy with the design, and, as early as 1944, had commented to a British government committee that a fully electronic device would be better. In 1939, Hungarian engineer
Peter Carl Goldmark Peter Carl Goldmark (born Péter Károly Goldmark; December 2, 1906 – December 7, 1977) was a Hungarian-American engineer who, during his time with Columbia Records, was instrumental in developing the long-playing microgroove 33 rpm phonogr ...
introduced an electro-mechanical system while at
CBS CBS Broadcasting Inc., commonly shortened to CBS, the abbreviation of its former legal name Columbia Broadcasting System, is an American commercial broadcast television and radio network serving as the flagship property of the CBS Entertainm ...
, which contained an Iconoscope sensor. The CBS field-sequential color system was partly mechanical, with a disc made of red, blue, and green filters spinning inside the television camera at 1,200 rpm, and a similar disc spinning in synchronization in front of the cathode-ray tube inside the receiver set. The system was first demonstrated to the
Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdicti ...
(FCC) on 29 August 1940, and shown to the press on 4 September."Color Television Success in Test", ''The New York Times'', 30 August 1940, p. 21. CBS began experimental color field tests using film as early as 28 August 1940, and live cameras by 12 November.
NBC The National Broadcasting Company (NBC) is an American English-language commercial broadcast television and radio network. The flagship property of the NBC Entertainment division of NBCUniversal, a division of Comcast, its headquarters are l ...
(owned by RCA) made its first field test of color television on 20 February 1941. CBS began daily color field tests on 1 June 1941. These color systems were not compatible with existing black-and-white
television sets A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube, is a device that combines a tuner, display, and loudspeakers, for the purpose of viewing and hearing television broadcasts, or using ...
, and, as no color television sets were available to the public at this time, viewing of the color field tests was restricted to RCA and CBS engineers and the invited press. The
War Production Board The War Production Board (WPB) was an agency of the United States government that supervised war production during World War II. President Franklin D. Roosevelt established it in January 1942, with Executive Order 9024. The WPB replaced the Su ...
halted the manufacture of television and radio equipment for civilian use from 22 April 1942, to 20 August 1945, limiting any opportunity to introduce color television to the general public. As early as 1940, Baird had started work on a fully electronic system he called Telechrome. Early Telechrome devices used two electron guns aimed at either side of a phosphor plate. The phosphor was patterned so the electrons from the guns only fell on one side of the patterning or the other. Using cyan and magenta phosphors, a reasonable limited-color image could be obtained. He also demonstrated the same system using monochrome signals to produce a 3D image (called " stereoscopic" at the time). A demonstration on 16 August 1944 was the first example of a practical color television system. Work on the Telechrome continued and plans were made to introduce a three-gun version for full color. However, Baird's untimely death in 1946 ended development of the Telechrome system. Similar concepts were common through the 1940s and 1950s, differing primarily in the way they re-combined the colors generated by the three guns. The
Geer tube Geer (; wa, Djer) is a Municipalities of Belgium, municipality of Wallonia located in the Liège Province, province of Liège, Belgium. On January 1, 2006, Geer had a total population of 2,854. The total area is 23.62 km² which gives a p ...
was similar to Baird's concept, but used small pyramids with the phosphors deposited on their outside faces, instead of Baird's 3D patterning on a flat surface. The
Penetron The penetron, short for penetration tube, is a type of limited-color television used in some military applications. Unlike a conventional color television, the penetron produces a limited color gamut, typically two colors and their combination. Pene ...
used three layers of phosphor on top of each other and increased the power of the beam to reach the upper layers when drawing those colors. The
Chromatron The Chromatron is a color television cathode ray tube design invented by Nobel prize-winner Ernest Lawrence and developed commercially by Paramount Pictures, Sony, Litton Industries and others. The Chromatron offered brighter images than convention ...
used a set of focusing wires to select the colored phosphors arranged in vertical stripes on the tube. One of the great technical challenges of introducing color broadcast television was the desire to conserve
bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...
, potentially three times that of the existing
black-and-white Black-and-white (B&W or B/W) images combine black and white in a continuous spectrum, producing a range of shades of grey. Media The history of various visual media began with black and white, and as technology improved, altered to color. ...
standards, and not use an excessive amount of
radio spectrum The radio spectrum is the part of the electromagnetic spectrum with frequencies from 0  Hz to 3,000 GHz (3  THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particula ...
. In the United States, after considerable research, the National Television Systems CommitteeNational Television System Committee (1951–1953), [Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplementary references cited in the Reports, and the Petition for adoption of transmission standards for color television before the Federal Communications Commission, n.p., 1953], 17 v. illus., diagrams., tables. 28 cm. LC Control No.:5402138
Library of Congress Online Catalog
/ref> approved an all-electronic system developed by
RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
, which encoded the color information separately from the brightness information and greatly reduced the resolution of the color information to conserve bandwidth. As black-and-white televisions could receive the same transmission and display it in black-and-white, the color system adopted is ackwards"compatible". ("Compatible Color", featured in RCA advertisements of the period, is mentioned in the song " America", of
West Side Story ''West Side Story'' is a musical conceived by Jerome Robbins with music by Leonard Bernstein, lyrics by Stephen Sondheim, and a book by Arthur Laurents. Inspired by William Shakespeare's play '' Romeo and Juliet'', the story is set in the mid ...
, 1957.) The brightness image remained compatible with existing black-and-white television sets at slightly reduced resolution, while color televisions could decode the extra information in the signal and produce a limited-resolution color display. The higher resolution black-and-white and lower resolution color images combine in the brain to produce a seemingly high-resolution color image. The NTSC standard represented a major technical achievement. The first color broadcast (the first episode of the live program '' The Marriage'') occurred on 8 July 1954, but during the following ten years most network broadcasts, and nearly all local programming, continued to be in black-and-white. It was not until the mid-1960s that color sets started selling in large numbers, due in part to the color transition of 1965 in which it was announced that over half of all network prime-time programming would be broadcast in color that fall. The first all-color prime-time season came just one year later. In 1972, the last holdout among daytime network programs converted to color, resulting in the first completely all-color network season. Early color sets were either floor-standing console models or tabletop versions nearly as bulky and heavy, so in practice they remained firmly anchored in one place. GE's relatively compact and lightweight
Porta-Color General Electric's Porta-Color was the first "portable" color television introduced in the United States in 1966. The Porta-Color set introduced a new variation of the shadow mask display tube. It had the electron guns arranged in an in-line confi ...
set was introduced in the spring of 1966. It used a
transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...
-based UHF tuner. The first fully transistorized color television in the United States was the Quasar television introduced in 1967. These developments made watching color television a more flexible and convenient proposition. The MOSFET (metal-oxide-semiconductor field-effect transistor, or MOS transistor) was invented by Mohamed M. Atalla and
Dawon Kahng Dawon Kahng ( ko, 강대원; May 4, 1931 – May 13, 1992) was a Korean-American electrical engineer and inventor, known for his work in solid-state electronics. He is best known for inventing the MOSFET (metal–oxide–semiconductor field-effe ...
at
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial Research and development, research and scientific developm ...
in 1959, and presented in 1960. By the mid-1960s,
RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
were using MOSFETs in their consumer television products.
RCA Laboratories The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
researchers W.M. Austin, J.A. Dean, D.M. Griswold and O.P. Hart in 1966 described the use of the MOSFET in television circuits, including
RF amplifier A radio-frequency power amplifier (RF power amplifier) is a type of electronic amplifier that converts a low-power radio-frequency signal into a higher-power signal. Typically, RF power amplifiers drive the antenna of a transmitter. Design goa ...
, low-level video, chroma and AGC circuits. The power MOSFET was later widely adopted for television receiver circuits. In 1972, sales of color sets finally surpassed sales of black-and-white sets. Color broadcasting in Europe was not standardized on the
PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...
format until the 1960s, and broadcasts did not start until 1967. By this point many of the technical issues in the early sets had been worked out, and the spread of color sets in Europe was fairly rapid. By the mid-1970s, the only stations broadcasting in black-and-white were a few high-numbered UHF stations in small markets, and a handful of low-power repeater stations in even smaller markets such as vacation spots. By 1979, even the last of these had converted to color and, by the early 1980s, B&W sets had been pushed into niche markets, notably low-power uses, small portable sets, or for use as
video monitor A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...
screens in lower-cost consumer equipment. By the late 1980s even these areas switched to color sets.


Digital

Digital television (DTV) is the transmission of audio and video by digitally processed and multiplexed signals, in contrast to the totally analog and channel separated signals used by analog television. Due to
data compression In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compressio ...
, digital television can support more than one program in the same channel bandwidth. It is an innovative service that represents the most significant evolution in television broadcast technology since color television emerged in the 1950s. Digital television's roots have been tied very closely to the availability of inexpensive, high performance computers. It was not until the 1990s that digital television became possible. Digital television was previously not practically possible due to the impractically high
bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...
requirements of uncompressed digital video, requiring around 200
Mbit/s In telecommunications, data-transfer rate is the average number of bits ( bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mu ...
for a standard-definition television (SDTV) signal, and over 1
Gbit/s In telecommunications, data-transfer rate is the average number of bits ( bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mu ...
for
high-definition television High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
(HDTV). A digital television service was proposed in 1986 by
Nippon Telegraph and Telephone , commonly known as NTT, is a Japanese telecommunications company headquartered in Tokyo, Japan. Ranked 55th in ''Fortune'' Global 500, NTT is the fourth largest telecommunications company in the world in terms of revenue, as well as the third la ...
(NTT) and the Ministry of Posts and Telecommunication (MPT) in Japan, where there were plans to develop an "Integrated Network System" service. However, it was not possible to practically implement such a digital television service until the adoption of DCT video compression technology made it possible in the early 1990s. In the mid-1980s, as Japanese
consumer electronics Consumer electronics or home electronics are electronic ( analog or digital) equipment intended for everyday use, typically in private homes. Consumer electronics include devices used for entertainment, communications and recreation. Usuall ...
firms forged ahead with the development of
HDTV High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
technology, the
MUSE In ancient Greek religion and mythology, the Muses ( grc, Μοῦσαι, Moûsai, el, Μούσες, Múses) are the inspirational goddesses of literature, science, and the arts. They were considered the source of the knowledge embodied in the ...
analog format proposed by
NHK , also known as NHK, is a Japanese public broadcaster. NHK, which has always been known by this romanized initialism in Japanese, is a statutory corporation funded by viewers' payments of a television license fee. NHK operates two terrestr ...
, a Japanese company, was seen as a pacesetter that threatened to eclipse U.S. electronics companies' technologies. Until June 1990, the Japanese MUSE standard, based on an analog system, was the front-runner among the more than 23 other technical concepts under consideration. Then, a U.S. company, General Instrument, demonstrated the possibility of a digital television signal. This breakthrough was of such significance that the
FCC The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdictio ...
was persuaded to delay its decision on an ATV standard until a digitally-based standard could be developed. In March 1990, when it became clear that a digital standard was possible, the FCC made a number of critical decisions. First, the Commission declared that the new ATV standard must be more than an enhanced analog signal, but be able to provide a genuine HDTV signal with at least twice the resolution of existing television images.(7) Then, to ensure that viewers who did not wish to buy a new digital television set could continue to receive conventional television broadcasts, it dictated that the new ATV standard must be capable of being "
simulcast Simulcast (a portmanteau of simultaneous broadcast) is the broadcasting of programmes/programs or events across more than one resolution, bitrate or medium, or more than one service on the same medium, at exactly the same time (that is, simulta ...
" on different channels.(8)The new ATV standard also allowed the new DTV signal to be based on entirely new design principles. Although incompatible with the existing
NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
standard, the new DTV standard would be able to incorporate many improvements. The last standards adopted by the FCC did not require a single standard for scanning formats, aspect ratios, or lines of resolution. This compromise resulted from a dispute between the
consumer electronics Consumer electronics or home electronics are electronic ( analog or digital) equipment intended for everyday use, typically in private homes. Consumer electronics include devices used for entertainment, communications and recreation. Usuall ...
industry (joined by some broadcasters) and the computer industry (joined by the
film industry The film industry or motion picture industry comprises the technological and commercial institutions of filmmaking, i.e., film production companies, film studios, cinematography, animation, film production, screenwriting, pre-production, p ...
and some public interest groups) over which of the two scanning processes—interlaced or progressive—would be best suited for the newer digital HDTV compatible display devices. Interlaced scanning, which had been specifically designed for older analogue CRT display technologies, scans even-numbered lines first, then odd-numbered ones. In fact, interlaced scanning can be looked at as the first video compression model as it was partly designed in the 1940s to double the image resolution to exceed the limitations of the television broadcast bandwidth. Another reason for its adoption was to limit the flickering on early CRT screens whose phosphor coated screens could only retain the image from the electron scanning gun for a relatively short duration. However interlaced scanning does not work as efficiently on newer display devices such as Liquid-crystal (LCD), for example, which are better suited to a more frequent progressive refresh rate.
Progressive scanning Progressive scanning (alternatively referred to as noninterlaced scanning) is a format of displaying, storing, or transmitting moving images in which all the lines of each frame are drawn in sequence. This is in contrast to interlaced video used ...
, the format that the computer industry had long adopted for computer display monitors, scans every line in sequence, from top to bottom. Progressive scanning in effect doubles the amount of data generated for every full screen displayed in comparison to interlaced scanning by painting the screen in one pass in 1/60-second, instead of two passes in 1/30-second. The computer industry argued that progressive scanning is superior because it does not "flicker" on the new standard of display devices in the manner of interlaced scanning. It also argued that progressive scanning enables easier connections with the Internet, and is more cheaply converted to interlaced formats than vice versa. The film industry also supported progressive scanning because it offered a more efficient means of converting filmed programming into digital formats. For their part, the consumer electronics industry and broadcasters argued that interlaced scanning was the only technology that could transmit the highest quality pictures then (and currently) feasible, i.e., 1,080 lines per picture and 1,920 pixels per line. Broadcasters also favored interlaced scanning because their vast archive of interlaced programming is not readily compatible with a progressive format. William F. Schreiber, who was director of the Advanced Television Research Program at the
Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
from 1983 until his retirement in 1990, thought that the continued advocacy of interlaced equipment originated from consumer electronics companies that were trying to get back the substantial investments they made in the interlaced technology. Digital television transition started in late 2000s. All governments across the world set the deadline for analog shutdown by 2010s. Initially, the adoption rate was low, as the first digital tuner-equipped television sets were costly. But soon, as the price of digital-capable television sets dropped, more and more households were converting to digital television sets. The transition is expected to be completed worldwide by mid to late 2010s.


Smart television

The advent of digital television allowed innovations like smart television sets. A smart television, sometimes referred to as connected TV or hybrid TV, is a television set or
set-top box A set-top box (STB), also colloquially known as a cable box and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of sign ...
with integrated Internet and
Web 2.0 Web 2.0 (also known as participative (or participatory) web and social web) refers to websites that emphasize user-generated content, ease of use, participatory culture and interoperability (i.e., compatibility with other products, systems, and ...
features, and is an example of
technological convergence Technological convergence is the tendency for technologies that were originally unrelated to become more closely integrated and even unified as they develop and advance. For example, watches, telephones, television, computers, and social media ...
between computers, television sets and set-top boxes. Besides the traditional functions of television sets and set-top boxes provided through traditional Broadcasting media, these devices can also provide Internet TV, online
interactive media Interactive media normally refers to products and services on digital computer-based systems which respond to the user's actions by presenting content such as text, moving image, animation, video and audio. Since its early conception, various f ...
, over-the-top content, as well as on-demand streaming media, and home networking access. These TVs come pre-loaded with an operating system. Smart TV should not to be confused with Internet TV, Internet Protocol television (IPTV) or with Web TV.
Internet television Streaming television is the digital distribution of television content, such as TV shows, as streaming media delivered over the Internet. Streaming television stands in contrast to dedicated terrestrial television delivered by over-the-air a ...
refers to the receiving of television content over the Internet instead of by traditional systems—terrestrial, cable and satellite (although Internet itself is received by these methods). IPTV is one of the emerging Internet television technology standards for use by television networks.
Web television Streaming television is the digital distribution of television content, such as TV shows, as streaming media delivered over the Internet. Streaming television stands in contrast to dedicated terrestrial television delivered by over-the-air ae ...
(WebTV) is a term used for programs created by a wide variety of companies and individuals for broadcast on Internet TV. A first patent was filed in 1994 (and extended the following year) for an "intelligent" television system, linked with data processing systems, by means of a digital or analog network. Apart from being linked to data networks, one key point is its ability to automatically download necessary software routines, according to a user's demand, and process their needs. Major TV manufacturers have announced production of smart TVs only, for middle-end and high-end TVs in 2015. Smart TVs have gotten more affordable compared to when they were first introduced, with 46 million of U.S. households having at least one as of 2019.


3D

3D television conveys depth perception to the viewer by employing techniques such as stereoscopic display, multi-view display,
2D-plus-depth 2D-plus-Depth is a stereoscopic video coding format that is used for 3D displays, such as Philips WOWvx. Philips discontinued work on the WOWvx line in 2009, citing "current market developments". Currently, this Philips technology is used by See ...
, or any other form of
3D display A 3D display is a display device capable of conveying depth to the viewer. Many 3D displays are stereoscopic displays, which produce a basic 3D effect by means of stereopsis, but can cause eye strain and visual fatigue. Newer 3D displays such ...
. Most modern 3D
television set A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube, is a device that combines a tuner, display, and loudspeakers, for the purpose of viewing and hearing television broadcasts, or using ...
s use an active shutter 3D system or a
polarized 3D system A polarized 3D system uses polarization glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye (an example of stereoscopy). To present stereoscopic images and films, two images are projected s ...
, and some are autostereoscopic without the need of glasses. Stereoscopic 3D television was demonstrated for the first time on 10 August 1928, by
John Logie Baird John Logie Baird FRSE (; 13 August 188814 June 1946) was a Scottish inventor, electrical engineer, and innovator who demonstrated the world's first live working television system on 26 January 1926. He went on to invent the first publicly dem ...
in his company's premises at 133 Long Acre, London. Baird pioneered a variety of 3D television systems using electromechanical and cathode-ray tube techniques. The first 3D television was produced in 1935. The advent of digital television in the 2000s greatly improved 3D television sets. Although 3D television sets are quite popular for watching 3D home media such as on Blu-ray discs, 3D programming has largely failed to make inroads with the public. Many 3D television channels which started in the early 2010s were shut down by the mid-2010s. According to DisplaySearch 3D televisions shipments totaled 41.45 million units in 2012, compared with 24.14 in 2011 and 2.26 in 2010. As of late 2013, the number of 3D TV viewers started to decline.


Broadcast systems


Terrestrial television

Programming is broadcast by television stations, sometimes called "channels", as stations are
licensed A license (or licence) is an official permission or permit to do, use, or own something (as well as the document of that permission or permit). A license is granted by a party (licensor) to another party (licensee) as an element of an agreeme ...
by their governments to broadcast only over assigned
channels Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austral ...
in the television
band Band or BAND may refer to: Places *Bánd, a village in Hungary *Band, Iran, a village in Urmia County, West Azerbaijan Province, Iran * Band, Mureș, a commune in Romania *Band-e Majid Khan, a village in Bukan County, West Azerbaijan Province, I ...
. At first, terrestrial broadcasting was the only way television could be widely distributed, and because
bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...
was limited, i.e., there were only a small number of
channels Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austral ...
available, government regulation was the norm. In the U.S., the
Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdicti ...
(FCC) allowed stations to broadcast advertisements beginning in July 1941, but required public service programming commitments as a requirement for a license. By contrast, the United Kingdom chose a different route, imposing a television license fee on owners of television reception equipment to fund the
British Broadcasting Corporation #REDIRECT BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board ex ...
(BBC), which had public service as part of its
Royal Charter A royal charter is a formal grant issued by a monarch under royal prerogative as letters patent. Historically, they have been used to promulgate public laws, the most famous example being the English Magna Carta (great charter) of 1215, but s ...
.
WRGB WRGB (channel 6) is a television station licensed to Schenectady, New York, United States, serving the Capital District as an affiliate of CBS. It is owned by Sinclair Broadcast Group alongside CW affiliate WCWN (channel 45, also licensed to Sc ...
claims to be the world's oldest television station, tracing its roots to an experimental station founded on 13 January 1928, broadcasting from the
General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable en ...
factory in
Schenectady, NY Schenectady () is a city in Schenectady County, New York, United States, of which it is the county seat. As of the 2020 census, the city's population of 67,047 made it the state's ninth-largest city by population. The city is in eastern New Y ...
, under the call letters W2XB. It was popularly known as "WGY Television" after its sister radio station. Later in 1928, General Electric started a second facility, this one in New York City, which had the call letters W2XBS and which today is known as
WNBC WNBC (channel 4) is a television station in New York City, serving as the flagship of the NBC network. It is owned and operated by the network's NBC Owned Television Stations division alongside Linden, New Jersey–licensed Telemundo stati ...
. The two stations were experimental in nature and had no regular programming, as receivers were operated by engineers within the company. The image of a
Felix the Cat Felix the Cat is a cartoon character created in 1919 by Pat Sullivan and Otto Messmer during the silent film era. An anthropomorphic black cat with white eyes, a black body, and a giant grin, he was one of the most recognized cartoon characte ...
doll rotating on a turntable was broadcast for 2 hours every day for several years as new technology was being tested by the engineers. On 2 November 1936, the
BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
began transmitting the world's first public regular high-definition service from the Victorian Alexandra Palace in north London. It therefore claims to be the birthplace of television broadcasting as we know it from now on. With the widespread adoption of cable across the United States in the 1970s and 1980s, terrestrial television broadcasts have been in decline; in 2013 it was estimated that about 7% of US households used an antenna. A slight increase in use began around 2010 due to switchover to
digital terrestrial television Digital terrestrial television (DTTV or DTT, or DTTB with "broadcasting") is a technology for terrestrial television in which land-based (terrestrial) television stations broadcast television content by radio waves to televisions in consumers' ...
broadcasts, which offered pristine image quality over very large areas, and offered an alternative to cable television (CATV) for
cord cutters In broadcast television, cord-cutting refers to the pattern of viewers, referred to as cord-cutters, cancelling their subscriptions to multichannel video programming distributor, multichannel television services available over cable or satellite ...
. All other countries around the world are also in the process of either shutting down analog terrestrial television or switching over to digital terrestrial television.


Cable television

Cable television is a system of broadcasting television programming to paying subscribers via radio frequency (RF) signals transmitted through coaxial cables or light pulses through
fiber-optic An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means t ...
cables. This contrasts with traditional terrestrial television, in which the television signal is transmitted over the air by radio waves and received by a television antenna attached to the television. In the 2000s, FM radio programming, high-speed Internet, telephone service, and similar non-television services may also be provided through these cables. The abbreviation CATV is sometimes used for cable television in the United States. It originally stood for Community Access Television or Community Antenna Television, from cable television's origins in 1948: in areas where over-the-air reception was limited by distance from transmitters or mountainous terrain, large "community antennas" were constructed, and cable was run from them to individual homes.


Satellite television

Satellite television is a system of supplying
television programming Broadcast programming is the practice of organizing or ordering (scheduling) of broadcast media shows, typically radio and television, in a daily, weekly, monthly, quarterly or season-long schedule. Modern broadcasters use broadcast automation ...
using broadcast signals relayed from
communication satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...
s. The signals are received via an outdoor parabolic reflector antenna usually referred to as a satellite dish and a low-noise block downconverter (LNB). A satellite receiver then decodes the desired television program for viewing on a
television set A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube, is a device that combines a tuner, display, and loudspeakers, for the purpose of viewing and hearing television broadcasts, or using ...
. Receivers can be external
set-top box A set-top box (STB), also colloquially known as a cable box and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of sign ...
es, or a built-in television tuner. Satellite television provides a wide range of channels and services, especially to geographic areas without terrestrial television or cable television. The most common method of reception is
direct-broadcast satellite television Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commo ...
(DBSTV), also known as "direct to home" (DTH). In DBSTV systems, signals are relayed from a
direct broadcast satellite Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna comm ...
on the Ku wavelength and are completely digital. Satellite TV systems formerly used systems known as
television receive-only Television receive-only (TVRO) is a term used chiefly in North America, South America to refer to the reception of satellite television from FSS-type satellites, generally on C-band analog; free-to-air and unconnected to a commercial DBS prov ...
. These systems received analog signals transmitted in the C-band spectrum from FSS type satellites, and required the use of large dishes. Consequently, these systems were nicknamed "big dish" systems, and were more expensive and less popular. The direct-broadcast satellite television signals were earlier analog signals and later digital signals, both of which require a compatible receiver. Digital signals may include
high-definition television High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
(HDTV). Some transmissions and channels are
free-to-air Free-to-air (FTA) services are television (TV) and radio services broadcast in unencrypted form, allowing any person with the appropriate receiving equipment to receive the signal and view or listen to the content without requiring a subscripti ...
or
free-to-view Free-to-view (FTV) is a term used for audiovisual transmissions that are provided free without any form of continual subscription . It differs from free-to-air (FTA) in that the program is encrypted. Free-to-view vs. free-to-air The free-to-vi ...
, while many other channels are
pay television Pay television, also known as subscription television, premium television or, when referring to an individual service, a premium channel, refers to subscription-based television services, usually provided by multichannel television providers, b ...
requiring a subscription. In 1945, British science fiction writer Arthur C. Clarke proposed a worldwide communications system which would function by means of three satellites equally spaced apart in earth orbit. This was published in the October 1945 issue of the ''
Wireless World ''Electronics World'' (''Wireless World'', founded in 1913, and in September 1984 renamed ''Electronics & Wireless World'') is a technical magazine in electronics and RF engineering aimed at professional design engineers. It is produced monthly in ...
'' magazine and won him the
Franklin Institute The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memori ...
's
Stuart Ballantine Medal {{notability, date=February 2018 The Stuart Ballantine Medal was a science and engineering award presented by the Franklin Institute, of Philadelphia, Pennsylvania, USA. It was named after the US inventor Stuart Ballantine. Laureates *1947 - Geo ...
in 1963. The first satellite television signals from Europe to North America were relayed via the Telstar satellite over the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
on 23 July 1962. The signals were received and broadcast in North American and European countries and watched by over 100 million. Launched in 1962, the ''
Relay 1 The Relay program consisted of Relay 1 and Relay 2, two early American satellites in elliptical medium Earth orbit. Both were primarily experimental communications satellites funded by NASA and developed by RCA. As of December 2, 2016, both sate ...
'' satellite was the first satellite to transmit television signals from the US to Japan. The first
geosynchronous A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...
communication satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...
, Syncom 2, was launched on 26 July 1963. The world's first commercial communications satellite, called
Intelsat I Intelsat I (nicknamed Early Bird for the proverb "The early bird catches the worm") was the first commercial communications satellite to be placed in geosynchronous orbit, on April 6, 1965. It was built by the Space and Communications Group of ...
and nicknamed "Early Bird", was launched into geosynchronous orbit on 6 April 1965. The first national network of television satellites, called Orbita, was created by the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
in October 1967, and was based on the principle of using the highly elliptical Molniya satellite for rebroadcasting and delivering of television
signals In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
to ground
downlink In a telecommunications network, a link is a communication channel that connects two or more devices for the purpose of data transmission. The link may be a dedicated physical link or a virtual circuit that uses one or more physical links or shar ...
stations. The first commercial North American satellite to carry television transmissions was Canada's geostationary Anik 1, which was launched on 9 November 1972.
ATS-6 ATS-6 (Applications Technology Satellite-6) was a NASA experimental satellite, built by Fairchild Space and Electronics Division It has been called the world's first educational satellite as well as world's first experimental Direct Broadca ...
, the world's first experimental educational and
Direct Broadcast Satellite Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna comm ...
(DBS), was launched on 30 May 1974. It transmitted at 860 MHz using wideband FM modulation and had two sound channels. The transmissions were focused on the Indian subcontinent but experimenters were able to receive the signal in Western Europe using home constructed equipment that drew on UHF television design techniques already in use.Long Distance Television Reception (TV-DX) For the Enthusiast, Roger W. Bunney, The first in a series of Soviet geostationary satellites to carry
Direct-To-Home Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commo ...
television,
Ekran : ''For the Soviet animation studio see page Studio Ekran'' Ekran (russian: "Экран", meaning ''"Screen"'') was a Soviet-Russian type of geostationary satellite, developed for a national system of Direct-To-Home television. The first satel ...
1, was launched on 26 October 1976. It used a 714 MHz UHF downlink frequency so that the transmissions could be received with existing UHF television technology rather than microwave technology.


Internet television

Internet television (Internet TV) (or online television) is the
digital distribution Digital distribution, also referred to as content delivery, online distribution, or electronic software distribution, among others, is the delivery or distribution of digital media content such as audio, video, e-books, video games, and other s ...
of television content via the Internet as opposed to traditional systems like terrestrial, cable, and satellite, although the Internet itself is received by terrestrial, cable, or satellite methods. Internet television is a general term that covers the delivery of television series, and other video content, over the Internet by video streaming technology, typically by major traditional television broadcasters. Internet television should not be confused with
Smart TV A smart TV, also known as a connected TV (CTV), is a traditional television set with integrated Internet and interactive Web 2.0 features, which allows users to stream music and videos, browse the internet, and view photos. Smart TVs are a techn ...
,
IPTV Internet Protocol television (IPTV) is the delivery of television content over Internet Protocol (IP) networks. This is in contrast to delivery through traditional terrestrial, satellite, and cable television formats. Unlike downloaded med ...
or with Web TV.
Smart television A smart TV, also known as a connected TV (CTV), is a traditional television set with integrated Internet and interactive Web 2.0 features, which allows users to stream music and videos, browse the internet, and view photos. Smart TVs are a techno ...
refers to the television set which has a built-in operating system. Internet Protocol television (IPTV) is one of the emerging Internet television technology standards for use by television networks.
Web television Streaming television is the digital distribution of television content, such as TV shows, as streaming media delivered over the Internet. Streaming television stands in contrast to dedicated terrestrial television delivered by over-the-air ae ...
is a term used for programs created by a wide variety of companies and individuals for broadcast on Internet television.


Sets

A television set, also called a television receiver, television, TV set, TV, or "telly", is a device that combines a tuner, display, an amplifier, and speakers for the purpose of viewing television and hearing its audio components. Introduced in the late 1920s in mechanical form, television sets became a popular consumer product after World War II in electronic form, using cathode-ray tubes. The addition of color to broadcast television after 1953 further increased the popularity of television sets and an outdoor antenna became a common feature of suburban homes. The ubiquitous television set became the display device for recorded media in the 1970s, such as Betamax and VHS, which enabled viewers to record TV shows and watch prerecorded movies. In the subsequent decades, Television sets were used to watch DVDs and Blu-ray Discs of movies and other content. Major TV manufacturers announced the discontinuation of CRT, DLP, plasma and fluorescent-backlit LCDs by the mid-2010s. Televisions since 2010s mostly use
LEDs A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (cor ...
. LEDs are expected to be gradually replaced by OLEDs in the near future.


Display technologies


Disk

The earliest systems employed a spinning disk to create and reproduce images. These usually had a low resolution and screen size and never became popular with the public.


CRT

The cathode-ray tube (CRT) is a
vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as ...
containing one or more
electron gun An electron gun (also called electron emitter) is an electrical component in some vacuum tubes that produces a narrow, collimated electron beam that has a precise kinetic energy. The largest use is in cathode-ray tubes (CRTs), used in nearly ...
s (a source of
electrons The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...
or electron emitter) and a
fluorescent Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, ...
screen used to view images. It has a means to accelerate and deflect the electron beam(s) onto the screen to create the images. The images may represent electrical
waveform In electronics, acoustics, and related fields, the waveform of a signal is the shape of its graph as a function of time, independent of its time and magnitude scales and of any displacement in time.David Crecraft, David Gorham, ''Electro ...
s ( oscilloscope), pictures (television, computer monitor),
radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...
targets or others. The CRT uses an evacuated glass envelope which is large, deep (i.e. long from front screen face to rear end), fairly heavy, and relatively fragile. As a matter of safety, the face is typically made of thick
lead glass Lead glass, commonly called crystal, is a variety of glass in which lead replaces the calcium content of a typical potash glass. Lead glass contains typically 18–40% (by weight) lead(II) oxide (PbO), while modern lead crystal, historically al ...
so as to be highly shatter-resistant and to block most
X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10  picometers to 10  nanometers, corresponding to frequencies in the range 30&nb ...
emissions, particularly if the CRT is used in a consumer product. In television sets and computer monitors, the entire front area of the tube is scanned repetitively and systematically in a fixed pattern called a raster. An image is produced by controlling the intensity of each of the three
electron beams Cathode rays or electron beam (e-beam) are streams of electrons observed in discharge tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow, due to el ...
, one for each additive primary color (red, green, and blue) with a
video signal Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) sy ...
as a reference. In all modern CRT monitors and televisions, the beams are bent by ''magnetic deflection'', a varying magnetic field generated by coils and driven by electronic circuits around the neck of the tube, although
electrostatic deflection Electrostatic deflection refers to a way for modifying the path of a beam of charged particles by the use of an electric field applied transverse to the path of the particles. The technique is called electro''static'' because the strength and di ...
is commonly used in oscilloscopes, a type of diagnostic instrument.


DLP

Digital Light Processing (DLP) is a type of
video projector A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. Video projectors use a very bright ultra-high-performance lamp (a special mercury arc lamp), X ...
technology that uses a
digital micromirror device The digital micromirror device, or DMD, is the microoptoelectromechanical system (MOEMS) that is the core of the trademarked DLP projection technology from Texas Instruments (TI). Texas Instrument's DMD was created by solid-state physicist and ...
. Some DLPs have a TV tuner, which makes them a type of TV display. It was originally developed in 1987 by Dr. Larry Hornbeck of
Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globa ...
. While the DLP imaging device was invented by Texas Instruments, the first DLP based projector was introduced by Digital Projection Ltd in 1997. Digital Projection and Texas Instruments were both awarded Emmy Awards in 1998 for invention of the DLP projector technology. DLP is used in a variety of display applications from traditional static displays to interactive displays and also non-traditional embedded applications including medical, security, and industrial uses. DLP technology is used in DLP front projectors (standalone projection units for classrooms and business primarily), but also in private homes; in these cases, the image is projected onto a projection screen. DLP is also used in DLP rear projection television sets and digital signs. It is also used in about 85% of
digital cinema Digital cinema refers to adoption of digital technology within the film industry to distribute or project motion pictures as opposed to the historical use of reels of motion picture film, such as 35 mm film. Whereas film reels have to be sh ...
projection.


Plasma

A plasma display panel (PDP) is a type of
flat panel display A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment. Flat-panel displays are thin, lightweight, provide better l ...
common to large television displays or larger. They are called " plasma" displays because the technology uses small cells containing
electrically Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...
charged
ionized Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule ...
gases Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...
, or what are in essence chambers more commonly known as
fluorescent lamp A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet ligh ...
s.


LCD

Liquid-crystal-display televisions (LCD TV) are television sets that use LCD display technology to produce images. LCD televisions are much thinner and lighter than cathode-ray tube (CRTs) of similar display size, and are available in much larger sizes (e.g., 90-inch diagonal). When manufacturing costs fell, this combination of features made LCDs practical for television receivers. LCDs come in two types: those using
cold cathode A cold cathode is a cathode that is not electrically heated by a filament.A negatively charged electrode emits electrons or is the positively charged terminal. For more, see field emission. A cathode may be considered "cold" if it emits more el ...
fluorescent lamps, simply called LCDs and those using LED as backlight called as LED-backlit LCD television, LEDs. In 2007, LCD television sets surpassed sales of CRT-based television sets worldwide for the first time, and their sales figures relative to other technologies accelerated. LCD television sets have quickly displaced the only major competitors in the large-screen market, the Plasma display panel and rear-projection television. In mid 2010s LCDs especially LEDs became, by far, the most widely produced and sold television display type. LCDs also have disadvantages. Other technologies address these weaknesses, including organic light-emitting diode, OLEDs, Field emission display, FED and Surface-conduction electron-emitter display, SED, but none of these have entered widespread production.


OLED

An OLED (organic light-emitting diode) is a light-emitting diode (LED) in which the emission (electromagnetic radiation), emissive electroluminescence, electroluminescent layer is a film of organic compound which emits light in response to an electric current. This layer of organic semiconductor is situated between two electrodes. Generally, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television set, television screens. It is also used for computer monitors, portable systems such as mobile phones, handheld game consoles and personal digital assistant, PDAs. There are two main groups of OLED: those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates a light-emitting electrochemical cell or LEC, which has a slightly different mode of operation. OLED displays can use either Passive matrix addressing, passive-matrix (PMOLED) or Active matrix addressing, active-matrix (AMOLED) addressing schemes. Active-matrix OLEDs require a thin-film transistor backplane to switch each individual pixel on or off, but allow for higher resolution and larger display sizes. An OLED display works without a backlight. Thus, it can display deep black levels and can be thinner and lighter than a liquid crystal display (LCD). In low ambient light conditions such as a dark room an OLED screen can achieve a higher contrast ratio than an LCD, whether the LCD uses
cold cathode A cold cathode is a cathode that is not electrically heated by a filament.A negatively charged electrode emits electrons or is the positively charged terminal. For more, see field emission. A cathode may be considered "cold" if it emits more el ...
fluorescent lamps or LED-backlit LCD television, LED backlight. OLEDs are expected to replace other forms of display in near future.


Display resolution


LD

Low-definition television or LDTV refers to television systems that have a lower screen resolution than standard-definition television systems such 240p (320*240). It is used in handheld television. The most common source of LDTV programming is the Internet, where mass distribution of higher-resolution video files could overwhelm computer servers and take too long to download. Many mobile phones and portable devices such as Apple Inc., Apple's iPod Nano, or Sony's PlayStation Portable use LDTV video, as higher-resolution files would be excessive to the needs of their small screens (QVGA, 320×240 and 480×272
pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the ...
s respectively). The current generation of iPod Nanos have LDTV screens, as do the first three generations of iPod Touch and iPhone (480×320). For the first years of its existence, YouTube offered only one, low-definition resolution of 320x240p at 30fps or less. A standard, consumer grade videotape can be considered SDTV due to its resolution (approximately 360 × 480i/576i).


SD

Standard-definition television or SDTV refers to two different resolutions:
576i 576i is a standard-definition digital video mode, originally used for digitizing analog television in most countries of the world where the utility frequency for electric power distribution is 50 Hz. Because of its close association with ...
, with 576 interlaced lines of resolution, derived from the European-developed
PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...
and SECAM systems; and
480i 480i is the video mode used for standard-definition digital television in the Caribbean, Japan, South Korea, Taiwan, Philippines, Laos, Western Sahara, and most of the Americas (with the exception of Argentina, Paraguay, and Uruguay). The ...
based on the American National Television System Committee
NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
system. SDTV is a television system that uses a resolution that is not considered to be either
high-definition television High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
(
720p 720p (1280×720 px; also called HD ready, standard HD or just HD) is a progressive HDTV signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcast ...
,
1080i 1080i (also known as Full HD or BT.709) is a combination of frame resolution and scan type. 1080i is used in high-definition television (HDTV) and high-definition video. The number "1080" refers to the number of horizontal lines on the scre ...
,
1080p 1080p (1920×1080 progressively displayed pixels; also known as Full HD or FHD, and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen ve ...
, 1440p, 4K UHDTV, and 8K UHD) or enhanced-definition television (EDTV 480p). In North America, digital SDTV is broadcast in the same 4:3 aspect ratio as NTSC signals with widescreen content being center cut. However, in other parts of the world that used the PAL or SECAM color systems, standard-definition television is now usually shown with a 16:9 aspect ratio (image), aspect ratio, with the transition occurring between the mid-1990s and mid-2000s. Older programs with a 4:3 aspect ratio are shown in the United States as 4:3 with non-ATSC countries preferring to reduce the horizontal resolution by anamorphically scaling a pillarboxed image.


HD

High-definition television (HDTV) provides a resolution that is substantially higher than that of standard-definition television. HDTV may be transmitted in various formats: *
1080p 1080p (1920×1080 progressively displayed pixels; also known as Full HD or FHD, and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen ve ...
: 1920×1080p: 2,073,600 pixels (~2.07 megapixels) per frame (video), frame *
1080i 1080i (also known as Full HD or BT.709) is a combination of frame resolution and scan type. 1080i is used in high-definition television (HDTV) and high-definition video. The number "1080" refers to the number of horizontal lines on the scre ...
: 1920×1080i: 1,036,800 pixels (~1.04 MP) per field (video), field or 2,073,600 pixels (~2.07 MP) per frame ** A non-standard CEA resolution exists in some countries such as 1440×1080i: 777,600 pixels (~0.78 MP) per field or 1,555,200 pixels (~1.56 MP) per frame *
720p 720p (1280×720 px; also called HD ready, standard HD or just HD) is a progressive HDTV signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcast ...
: 1280×720p: 921,600 pixels (~0.92 MP) per frame


UHD

Ultra-high-definition television (also known as Super Hi-Vision, Ultra HD television, UltraHD, UHDTV, or XVGA#UHD (4K) (3840×2160), UHD) includes 4K resolution#Resolutions, 4K UHD (2160p) and 8K resolution#Resolutions, 8K UHD (4320p), which are two digital video formats proposed by NHK Science & Technology Research Laboratories and defined and approved by the International Telecommunication Union (ITU). The Consumer Electronics Association announced on 17 October 2012, that "Ultra High Definition", or "Ultra HD", would be used for displays that have an display aspect ratio, aspect ratio of at least 16:9 and at least one digital input capable of carrying and presenting natural video at a minimum resolution of 3840×2160 pixels.


Market share

North American consumers purchase a new television set on average every seven years, and the average household owns 2.8 televisions. , 48 million are sold each year at an average price of $460 and size of .


Content


Programming

Getting TV programming shown to the public can happen in many other ways. After production, the next step is to market and deliver the product to whichever 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 television producers to do the same. # Broadcast 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 not be managed by the originating producer. In many cases, other companies, television 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. First-run programming is increasing on subscription services outside of the United States, but few domestically produced programs are syndicated on domestic
free-to-air Free-to-air (FTA) services are television (TV) and radio services broadcast in unencrypted form, allowing any person with the appropriate receiving equipment to receive the signal and view or listen to the content without requiring a subscripti ...
(FTA) elsewhere. This practice is increasing, however, generally on digital-only FTA channels or with subscriber-only, first-run material appearing on FTA. Unlike United States, repeat FTA screenings of an FTA network program usually only occur on that network. Also, Network affiliate, affiliates rarely buy or produce non-network programming that is not focused on local programming.


Genres

Television genres include a broad range of programming types that entertain, inform, and educate viewers. The most expensive entertainment genres to produce are usually dramas and dramatic miniseries. However, other genres, such as historical Western genres, may also have high production costs. Pop culture entertainment genres include action-oriented shows such as police, crime, detective dramas, horror, or thriller shows. As well, there are also other variants of the drama genre, such as medical dramas and daytime soap operas. Sci-fi series can fall into either the drama or action category, depending on whether they emphasize philosophical questions or high adventure. Comedy is a popular genre which includes situation comedy (sitcom) and animated series for the adult demographic such as Comedy Central's ''South Park''. The least expensive forms of entertainment programming genres are game shows, talk shows, variety shows, and reality television. Game shows feature contestants answering questions and solving puzzles to win prizes. Talk shows contain interviews with film, television, music and sports celebrity, celebrities and public figures. Variety shows feature a range of musical performers and other entertainers, such as comedians and magicians, introduced by a host or Master of Ceremonies. There is some crossover between some talk shows and variety shows because leading talk shows often feature performances by bands, singers, comedians, and other performers in between the interview segments. Reality television series "regular" people (i.e., not actors) facing unusual challenges or experiences ranging from arrest by police officers (''Cops (TV series), COPS'') to significant weight loss (''The Biggest Loser''). A derived version of reality shows depicts celebrities doing mundane activities such as going about their everyday life (''The Osbournes'', ''Snoop Dogg's Father Hood'') or doing regular jobs (''The Simple Life''). Fictional television programs that some television scholars and broadcasting advocacy groups argue are "quality television", include series such as ''Twin Peaks'' and ''The Sopranos''. Kristin Thompson argues that some of these television series exhibit traits also found in art films, such as psychological realism, narrative complexity, and ambiguous plotlines. Nonfiction television programs that some television scholars and broadcasting advocacy groups argue are "quality television", include a range of serious, noncommercial, programming aimed at a niche audience, such as documentaries and public affairs shows.


Funding

Around the world, broadcast television is financed by government, advertising, licensing (a form of tax), subscription, or any combination of these. To protect revenues, subscription television channels are usually encrypted to ensure that only subscribers receive the decryption codes to see the signal. Unencrypted channels are known as free to air or FTA. In 2009, the global TV market represented 1,217.2 million TV households with at least one TV and total revenues of 268.9 billion EUR (declining 1.2% compared to 2008). North America had the biggest TV revenue market share with 39% followed by Europe (31%), Asia-Pacific (21%), Latin America (8%), and Africa and the Middle East (2%). Globally, the different TV revenue sources divide into 45–50% TV advertising revenues, 40–45% subscription fees and 10% public funding.


Advertising

Television's broad reach makes it a powerful and attractive medium for advertisers. Many television networks and stations sell blocks of broadcast time to advertisers ("sponsors") to fund their programming.Karen Hornick
"That Was the Year That Was" ''American Heritage'', Oct. 2006.
Television advertisements (variously called a television commercial, commercial or ad in American English, and known in British English as an advert) is a span of television programming produced and paid for by an organization, which conveys a message, typically to market a product or service. Advertising revenue provides a significant portion of the funding for most privately owned television networks. The vast majority of television advertisements today consist of brief advertising spots, ranging in length from a few seconds to several minutes (as well as program-length infomercials). Advertisements of this sort have been used to promote a wide variety of goods, services and ideas since the beginning of television. The effects of television advertising upon the viewing public (and the effects of mass media in general) have been the subject of discourse by philosophers including Marshall McLuhan. The viewership of television programming, as measured by companies such as Nielsen Media Research, is often used as a metric for television advertisement placement, and consequently, for the rates charged to advertisers to air within a given network, television program, or time of day (called a "daypart"). In many countries, including the United States, television Campaign advertising, campaign advertisements are considered indispensable for a political campaign. In other countries, such as France, political advertising on television is heavily restricted, while some countries, such as Norway, completely ban political advertisements. The first official, paid television advertisement was broadcast in the United States on 1 July 1941, over New York station WNBT (now
WNBC WNBC (channel 4) is a television station in New York City, serving as the flagship of the NBC network. It is owned and operated by the network's NBC Owned Television Stations division alongside Linden, New Jersey–licensed Telemundo stati ...
) before a baseball game between the Brooklyn Dodgers and Philadelphia Phillies. The announcement for Bulova watches, for which the company paid anywhere from $4.00 to $9.00 (reports vary), displayed a WNBT test pattern modified to look like a clock with the hands showing the time. The Bulova logo, with the phrase "Bulova Watch Time", was shown in the lower right-hand quadrant of the test pattern while the second hand swept around the dial for one minute. The first TV ad broadcast in the U.K. was on ITV (TV network), ITV on 22 September 1955, advertising Gibbs SR toothpaste. The first TV ad broadcast in Asia was on Nippon Television in Tokyo on 28 August 1953, advertising Seikosha (now Seiko), which also displayed a clock with the current time.


United States

Since inception in the US in 1941, television commercials have become one of the most effective, persuasive, and popular methods of selling products of many sorts, especially consumer goods. During the 1940s and into the 1950s, programs were hosted by single advertisers. This, in turn, gave great creative control to the advertisers over the content of the show. Perhaps due to the quiz show scandals in the 1950s, networks shifted to the magazine concept, introducing advertising breaks with other advertisers. U.S. advertising rates are determined primarily by Nielsen ratings. The time of the day and popularity of the channel determine how much a TV commercial can cost. For example, it can cost approximately $750,000 for a 30-second block of commercial time during the highly popular singing competition ''American Idol'', while the same amount of time for the Super Bowl can cost several million dollars. Conversely, lesser-viewed time slots, such as early mornings and weekday afternoons, are often sold in bulk to producers of infomercials at far lower rates. In recent years, the paid program or infomercial has become common, usually in lengths of 30 minutes or one hour. Some Pharmaceutical company, drug companies and other businesses have even created "news" items for broadcast, known in the industry as video news releases, paying program directors to use them. Some television programs also deliberately place products into their shows as advertisements, a practice started in feature films and known as product placement. For example, a character could be drinking a certain kind of soda, going to a particular Restaurant chain, chain restaurant, or driving a certain make of car. (This is sometimes very subtle, with shows having vehicles provided by manufacturers for low cost in exchange as a product placement). Sometimes, a specific brand or Trademark, trade mark, or music from a certain artist or group, is used. (This excludes guest appearances by artists who perform on the show.)


United Kingdom

The TV regulator oversees TV advertising in the United Kingdom. Its restrictions have applied since the early days of commercially funded TV. Despite this, an early TV mogul, Roy Thomson, 1st Baron Thomson of Fleet, Roy Thomson, likened the broadcasting licence as being a "licence to print money". Restrictions mean that the big three national commercial TV channels: ITV (TV channel), ITV, Channel 4, and Channel 5 (UK), Channel 5 can show an average of only seven minutes of advertising per hour (eight minutes in the peak period). Other broadcasters must average no more than nine minutes (twelve in the peak). This means that many imported TV shows from the U.S. have unnatural pauses where the British company does not use the narrative breaks intended for more frequent U.S. advertising. Advertisements must not be inserted in the course of certain specific proscribed types of programs which last less than half an hour in scheduled duration; this list includes any news or current affairs programs, documentaries, and programs for children; additionally, advertisements may not be carried in a program designed and broadcast for reception in schools or in any religious broadcasting service or other devotional program or during a formal Royal ceremony or occasion. There also must be clear demarcations in time between the programs and the advertisements. The
BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
, being strictly non-commercial, is not allowed to show advertisements on television in the U.K., although it has many advertising-funded channels abroad. The majority of its budget comes from television license fees (see below) and broadcast syndication, the sale of content to other broadcasters.


Ireland

Broadcast advertising is regulated by the Broadcasting Authority of Ireland.


Subscription

Some TV channels are partly funded from subscriptions; therefore, the signals are encrypted during broadcast to ensure that only the paying subscribers have access to the decryption codes to watch
pay television Pay television, also known as subscription television, premium television or, when referring to an individual service, a premium channel, refers to subscription-based television services, usually provided by multichannel television providers, b ...
or specialty channels. Most subscription services are also funded by advertising.


Taxation or license

Television services in some countries may be funded by a television licence or a form of taxation, which means that advertising plays a lesser role or no role at all. For example, some channels may carry no advertising at all and some very little, including: * Australia (Australian Broadcasting Corporation, ABC Television) * Belgium (VRT (broadcaster), VRT for Flanders and RTBF for Wallonia) * Denmark (Danmarks Radio, DR) * Ireland (RTÉ) * Japan (
NHK , also known as NHK, is a Japanese public broadcaster. NHK, which has always been known by this romanized initialism in Japanese, is a statutory corporation funded by viewers' payments of a television license fee. NHK operates two terrestr ...
) * Norway (NRK) * Sweden (Sveriges Television, SVT) * Switzerland (Swiss Broadcasting Corporation, SRG SSR) * Taiwan, Republic of China (Taiwan) (Public Television Service, PTS) * United Kingdom (BBC Television) * United States (PBS) The
British Broadcasting Corporation #REDIRECT BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board ex ...
's TV service carries no television advertising on its UK channels and is funded by an annual television licence paid by the occupiers of premises receiving live telecasts. it was estimated that approximately 26.8 million UK private domestic households owned televisions, with approximately 25 million TV licences in all premises in force as of 2010. This television license fee is set by the government, but the BBC is not answerable to or controlled by the government. two main BBC TV channels were watched by almost 90% of the population each week and overall had 27% share of total viewing, despite the fact that 85% of homes were multi-channel, with 42% of these having access to 200 free-to-air channels via satellite and another 43% having access to 30 or more channels via Freeview (UK), Freeview. the licence that funds the advertising-free BBC TV channels cost £159 for a colour TV Licence and £53.50 for a black and white TV Licence (free or reduced for some groups). The Australian Broadcasting Corporation's television services in Australia carry no advertising by external sources; it is banned under the ''Australian Broadcasting Corporation Act 1983'', which also ensures its the editorial independence. The ABC receives most of its funding from the Australian Government (some revenue is received from its ABC Commercial, Commercial division), but it has suffered progressive funding cuts under Liberal Party of Australia, Liberal governments since the 1996 Howard government, with particularly deep cuts in 2014 under the Turnbull government, and an ongoing indexation freeze . The funds provide for the ABC Television (Australian TV network), ABC's television, ABC Radio (Australia), radio, ABC Online, online, and international outputs, although ABC Australia (Southeast Asian TV channel), ABC Australia, which broadcasts throughout the Asia-Pacific region, receives additional funds through DFAT and some advertising on the channel. In France, government-funded channels carry advertisements, yet those who own television sets have to pay an annual tax ("la redevance audiovisuelle"). In Japan,
NHK , also known as NHK, is a Japanese public broadcaster. NHK, which has always been known by this romanized initialism in Japanese, is a statutory corporation funded by viewers' payments of a television license fee. NHK operates two terrestr ...
is paid for by license fees (known in Japanese as ). The broadcast law that governs NHK's funding stipulates that any television equipped to receive NHK is required to pay. The fee is standardized, with discounts for office workers and students who commute, as well a general discount for residents of Okinawa prefecture.


Broadcast programming

Broadcast programming, or TV listings in the United Kingdom, is the practice of organizing television programs in a schedule, with broadcast automation used to regularly change the scheduling of TV programs to build an audience for a new show, retain that audience, or compete with other broadcasters' programs.


Social aspects

Television has played a pivotal role in the socialization of the 20th and 21st centuries. There are many aspects of television that can be addressed, including negative issues such as media violence. Current research is discovering that individuals suffering from social isolation can employ television to create what is termed a parasocial or faux relationship with characters from their favorite television shows and movies as a way of deflecting feelings of loneliness and social deprivation.Butler, Fionnuala, Cynthia Pickett. "Imaginary Friends." ''Scientific American''. 28 July 2009. Web. 26 March 2010. http://www.scientificamerican.com/article.cfm?id=imaginary-friends Several studies have found that educational television has many advantages. The article "The Good Things about Television" argues that television can be a very powerful and effective learning tool for children if used wisely. With respect to faith, many Christian denominations use television for religious broadcasting.


Religious opposition

Methodist denominations in the conservative holiness movement, such as the Allegheny Wesleyan Methodist Connection and the Evangelical Wesleyan Church, eschew the use of the television. Some Baptists, such as those affiliated with Pensacola Christian College, also eschew television. Many Traditional Catholic congregations such as the Society of Saint Pius X (SSPX), as with Laestadianism, Laestadian Lutherans, and Conservative Anabaptists such as the Dunkard Brethren Church, oppose the presence of television in the household, teaching that it is an occasion of sin.


Negative impacts

Children, especially those aged 5 or younger, are at risk of injury from falling televisions. A Cathode-ray tube, CRT-style television that falls on a child will, because of its weight, hit with the equivalent force of falling multiple stories from a building. Newer Flat-panel display, flat-screen televisions are "top-heavy and have narrow bases", which means that a small child can easily pull one over. , TV tip-overs were responsible for more than 10,000 injuries per year to children in the U.S., at a cost of more than $8 million per year in Emergency medicine, emergency care. A 2017 study in ''The Journal of Human Resources'', found that exposure to cable television reduced cognitive ability and high school graduation rates for boys. This effect was stronger for boys from more educated families. The article suggests a mechanism where light television entertainment crowds out more cognitively stimulating activities. With high lead content in cathode-ray tube, CRTs and the rapid diffusion of new flat-panel display technologies, some of which (LCDs) use lamps which contain mercury (element), mercury, there is growing concern about electronic waste from discarded televisions. Related occupational health concerns exist, as well, for disassemblers removing copper wiring and other materials from CRTs. Further environmental concerns related to television design and use relate to the devices' increasing electrical energy requirements.


See also

* B-television * Broadcast-safe * Content discovery platform * Information-action ratio * List of countries by number of television broadcast stations * List of television manufacturers * List of years in television * Lists of television channels * Media psychology * MicroLED * Sign language on television * Telephilia * Television studies * TV accessory


References


Further reading

* * Pierre Bourdieu, ''On Television'', The New Press, 2001. * Tim Brooks and Earle March, ''The Complete Guide to Prime Time Network and Cable TV Shows'', 8th ed., Ballantine, 2002. * Jacques Derrida and Bernard Stiegler, ''Echographies of Television'', Polity Press, 2002. * David E. Fisher and Marshall J. Fisher, ''Tube: the Invention of Television'', Counterpoint, Washington, D.C., 1996, . * Steven Berlin Johnson, Steven Johnson, ''Everything Bad is Good for You: How Today's Popular Culture Is Actually Making Us Smarter'', New York, Riverhead (Penguin), 2005, 2006, . * * Jerry Mander, ''Four Arguments for the Elimination of Television'', Perennial, 1978. * Jerry Mander, ''In the Absence of the Sacred'', Sierra Club Books, 1992, . * Neil Postman, ''Amusing Ourselves to Death: Public Discourse in the Age of Show Business'', New York, Penguin US, 1985, . * Evan I. Schwartz, ''The Last Lone Inventor: A Tale of Genius, Deceit, and the Birth of Television'', New York, Harper Paperbacks, 2003, . * Beretta E. Smith-Shomade, ''Shaded Lives: African-American Women and Television'', Rutgers University Press, 2002. * Alan Taylor, ''We, the Media: Pedagogic Intrusions into US Mainstream Film and Television News Broadcasting Rhetoric'', Peter Lang, 2005, . * Amanda D. Lotz, ''The Television Will Be Revolutionized'', New York University Press,


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