Encyclopedia  |   World Factbook  |   World Flags  |   Reference Tables  |   List of Lists     
   Academic Disciplines  |   Historical Timeline  |   Themed Timelines  |   Biographies  |   How-Tos     
Sponsor by The Tattoo Collection
Television
Main Page | See live article | Alphabetical index

Television

See TV (disambiguation) for other uses of TV.

Television is a telecommunication system for broadcasting and receiving moving pictures and sound over a distance. The term has come to refer to all the aspects of television programming and transmission as well. The word television is a hybrid word, coming from both Greek and Latin. "Tele-" is Greek for "far", while "-vision" is from the Latin "visio", meaning "vision" or "sight".

Table of contents
1 History
2 TV standards
3 TV aspect ratio
4 Aspect ratio incompatibility
5 New developments
6 TV sets
7 Advertising
8 Geographical Usage
9 Distribution
10 Health effects
11 Colloquial names
12 Related articles
13 External links
14 Further Reading

History

The development of television technology can be partitioned along two lines: those developments that depended upon both mechanical and electronic principles, and those which are purely electronic. From the latter descended all modern televisons, but these would not have been possible without discoveries and insights from the mechanical systems.

Electromechanical Television

Paul Gottlieb Nipkow proposed and patented the first electromechanical television system in 1884. Nipkow's spinning disk design is credited with being the first television image rasterizer, but it is believed that he never built a prototype to prove the design (it wasn't until 1907 that developments in amplification tube technology made the design practical).

In 1907–1910, Boris Rosing and his student Vladimir Zworykin demonstrated a television system that used a mechanical mirror-drum scanner in the transmitter and the electronic Braun tube (cathode ray tube) in the receiver. Rosing dissapeared during the Bolshevik revolution of 1917, but Zworykin later went to work for RCA to build a purely electronic television, the design of which was eventually found to violate patents by Philo Taylor Farnsworth.

A semi-mechanical analogue television system was first demonstrated in London in February 1924 by John Logie Baird with an image of Felix the Cat and a moving picture by Baird on October 30, 1925. Baird's system was eventually adopted by the BBC, who discontinued its use in 1937 in favor of purely electronic television.

Electronic Television

Although the discoveries of Nipkov, Rosing, Baird and others were extraordinary, little of their technology is used in modern televsion. By 1934, all electromechanical television systems were outmoded.

A. Campbell Swinton wrote a letter to Nature on the 18th June 1908 describing his concept of electronic television using the cathode ray tube invented by Karl Ferdinand Braun. He proposed using an electron beam in both the camera and the receiver, which could be steered electronically to produce moving pictures. He lectured on the subject in 1911 and displayed circuit diagrams, but no one, including Swinton, knew how to realize the design. His system was never built.

A fully electronic system was first demonstrated by Philo Taylor Farnsworth in the autumn of 1927. Farnsworth, a Mormon farm boy from Idaho, first envisioned his system at age 14. He discussed the idea with his high school chemistry teacher, who could think of no reason why it would not work (Farnsworth would later credit this teacher, Justin Tolman, as providing key insights into his invention). He continued to persue the idea at Brigham Young Academy (now Brigham Young University). At age 21, he demonstrated a working system at his own laboratory in San Francisco. His breakthrough freed television from reliance on spinning discs and other mechanical parts. All modern picture tube televisions descend directly from his design.

Vladimir Zworykin is also sometimes cited as the father of electronic television because of his invention of the iconoscope in 1923 and his invention of the kinescope in 1929. His design was one of the first to demonstrate a television system with all the features of modern picture tubes. His previous work with Rosing on electromechanical television gave him key insights into how to produce such a system, but his (and RCA's) claim to being its original inventor was largely invalidated by three facts: a) Zworykin's 1923 patent presented an incomplete design, incapable of working in its given form (it was not until 1933 that Zworykin achieved a working implementation), b) the 1923 patent application was not granted until 1938, and not until it had been seriously revised, and c) courts eventually found that RCA was in violation of the television design patented by Philo Taylor Farnsworth, whose lab Zworykin had visited while working on his designs for RCA.

The controversy over whether it was first Farnsworth or Zworykin who invented modern television is still hotly debated today. Some of this debate stems from the fact that while Farnsworth appears to have gotten there first, it was RCA that first marketed working television sets, and it was RCA employees who first wrote the history of television. Even though Farnsworth eventually won the legal battle over this issue, he was never able to fully capitalize financially on his invention.

Broadcast Television

The first long distance public television broadcast was from Washington, DC to New York City and occurred on April 7, 1927. The image shown was of then Commerce Secretary Herbert Hoover. The first analogue service was WGY, Schenectady, New York inaugurated on May 11 1928. The first British Television Play, "The Man with the Flower in his Mouth", was transmitted in July 1930. CBS's New York City station began broadcasting the first regular seven days a week television schedule in the U. S. on July 21, 1931. The first broadcast included Mayor James J. Walker, Kate Smith, and George Gershwin. The first all-electronic television service was started in Los Angeles, CA by Don Lee Broadcasting. Their start date was December 23, 1931 on W6XAO - later KTSL. Originally, mechanical equipment was used, but in June of 1936 a 300 line all-electronic service was started.

In 1932 the BBC launched a service using Baird's 30-line system and these transmissions continued until 11th September 1935. On November 2, 1936 the BBC began broadcasting a dual-system service, alternating on a weekly basis between Marconi-EMI's high-resolution (405 lines per picture) service and Baird's improved 240-line standard from Alexandra Palace in London. Six months later, the corporation decided that Marconi-EMI's electronic picture gave the superior picture, and adopted that as their standard. This service is described as "the world's first regular high-definition public television service", since a regular television service had been broadcast earlier on a 180-line standard in Germany. The outbreak of the Second World War caused the service to be suspended. TV transmissions only resumed from Alexandra Palace in 1946.

The first regular television transmissions in Canada began in 1952 when the CBC put two stations on the air, one in Montreal, Quebec on September 6, and another in Toronto, Ontario two days later.

The first live transcontinental television broadcast took place in San Francisco, California from the Japanese Peace Treaty Conference on September 4, 1955. In 1958, the CBC completed the longest television network in the world, from Sydney, Nova Scotia to Victoria, British Columbia.

Programming is broadcast on television stations (sometimes called channels). At first, terrestrial broadcasting was the only way television could be distributed. Because bandwidth was limited, government regulation was normal. In the US, the Federal Communications Commission allowed stations to broadcast advertisements, but insisted on public service programming commitments as a requirement for a license. By contrast, the United Kingdom chose a different route, imposing a television licence fee (effectively a tax) to fund the BBC, which had public service as part of its Royal Charter. Development of cable and satellite means of distribution in the 1970s pushed businessmen to target channels towards a certain audience, and enabled the rise of subscription-based television channels, such as HBO and Sky. Practically every country in the world now has developed at least one television channel. Television has grown up all over the world, enabling every country to share aspects of their culture and society with others.

By the late 1980s, 98% of all homes in the U.S. had at least one TV set. On average, Americans watch four hours of television per day. An estimated two-thirds of Americans got most of their news about the world from TV, and nearly half got all of their news from TV.

TV standards

See broadcast television systems.

There many means of distributing television broadcasts, including both analogue and digital versions of:

TV aspect ratio

All of these early TV systems shared the same
aspect ratio of 4:3 which was chosen to match the Academy Ratio used in cinema films at the time. This ratio was also square enough to be conveniently viewed on round cathode-ray tubes (CRTs), which were all that could be produced given the manufacturing technology of the time. (Today's CRT technology allows the manufacture of much wider tubes, and the flat screen technologies which are becoming steadily more popular have no aspect ratio limitations at all.)

In the 1950s, movie studios moved towards wide-screen aspect ratios such as Cinerama in an effort to distance their product from television. Although this was just a gimmick, and many have argued that it is actually a disadvantage when showing objects that are tall instead of panoramic, wide-screen still is being pushed today.

The switch to digital television systems has been used as an opportunity to change the standard television picture format from the old ratio of 4:3 (1.33:1) to an aspect ratio of 16:9 (1.78:1). This enables TV to get closer to the aspect ratio of modern wide-screen movies, which range from 1.85:1 to 2.35:1. The 16:9 format was first introduced on "widescreen" DVDs. DVD provides two methods for transporting wide-screen content, the better of which uses what is called anamorphic wide-screen format. This format is very similar to the technique used to fit a wide-screen movie frame inside a 1.33:1 35mm film frame. The image is squashed horizontally when recorded, then expanded again when played back. The U.S. ATSC HDTV system uses straight wide-screen format, no image squashing or expanding is used.

There is no technical reason why the introduction of digital TV demands this aspect ratio change, however it has been decided to introduce these changes for marketing reasons.

Aspect ratio incompatibility

Displaying a wide-screen original image on a conventional aspect television screen presents a considerable problem since the image must be shown either: A conventional aspect image on a wide screen television can be shown: A common compromise is to shoot or create material at an aspect ratio of 14:9, and to lose some image at each side for 4:3 presentation, and some image at top and bottom for 16:9 presentation.

Horizontal expansion has advantages in situations in which several people are watching the same set, as it compensates for watching at an oblique angle.

New developments

TV sets

The earliest television sets were radios with the addition of a television device consisting of a
neon tube with a mechanically spinning disk (the Nipkow disk, invented by Paul Gottlieb Nipkow) that produced a red postage-stamp size image . The first publicly broadcast electronic service was in Germany in March 1935. It had 180 lines of resolution and was only available in 22 public viewing rooms. One of the first major broadcasts involved the 1936 Berlin Olympics. The Germans had a 441 line system in the autumn of 1937. (Source: Early Electronic TV)

Television usage skyrocketed after World War II with war-related technological advances and additional disposable income. (1930s TV receivers cost the equivalent of $7000 today (2001) and had little available programming.)

For many years different countries used different technical standards. France initially adopted the German 441-line standard but later upgraded to 819 lines, which gave the highest picture definition of any analogue TV system, approximately four times the resolution of the British 405 line system. Eventually the whole of Europe switched to the 625 line standard, once more following Germany's example. Meanwhile in North America the original 525 line standard was retained.

Television in its original and still most popular form involves sending images and sound over radio waves in the VHF and UHF bands, which are received by a receiver (a television set). In this sense, it is an extension of radio. Broadcast television requires an antenna (UK: aerial). This can be an external antenna mounted outside or smaller antennas mounted on or near the television. Typically this is an adjustable dipole antenna called "rabbit ears" for the VHF band and a small loop antenna for the UHF band.

Color television became available in the U.S. on December 30 of 1953, backed by the CBS network. The government approved the color broadcast system proposed by CBS, but when RCA came up with a subcarrier system that made it possible to view color broadcasts in black and white on unmodified old black and white TV sets, CBS dropped their own proposal and used the new one.

While many programs had unveiled "test broadcasts" in which a certain episode would be broadcast in color, NBC was the first network to have a regularly scheduled color program on the air (Bonanza, starting in 1959).

European colour television was developed somewhat later, in the 1960s, and was hindered by a continuing division on technical standards. The first colour broadcast in Europe was by BBC TWO (then BBC2) in the UK. The German PAL system was eventually adopted by West Germany, the UK, Australia, New Zealand, much of Africa, Asia and South America, and most Western European countries except France. France produced its own PAL-derived SECAM standard, which was eventually adopted in much of Eastern Europe as a form of cultural protectionism. Both systems brodcast on UHF frequencies and adopted a higher-definition 625 line system, with a lower frame rate.

Starting in the [[1990s, modern television sets diverged into three different trends:

There are many kinds of video monitors used in modern TV sets. The most common are direct view CRTss for up to 40" or 100cm (in 4:3) and 46" or 115cm (in 16:9) diagonally. Most big screen TVs (up to over 100") use projection technology. Three types of projection systems are used in projection TVs: CRT-based, LCD-based, and reflective imaging chip-based. Modern advances have brought flat screens to TV that use active matrix LCD or plasma display technology. Flat panel plasma and LCD displays are as little as 4" or 10cm thick and can be hung on a wall like a picture. They are extremely attractive and space-saving but they remain expensive.

Nowadays some TVs include a port to connect peripherals to it or to connect the set to an A/V home network (HAVI), like LG RZ-17LZ10 that includes a USB port, where one can connect a mouse, keyboard and so on (for WebTV, now branded MSN TV).

Even for simple video, there are five standard ways to connect a device. These are as follows:

Advertising

From the earliest days of the medium, television has been used as a vehicle for
advertising. Since their inception in the USA in the late 1940s, TV commercialss have become far and away the most effective, most pervasive, and most popular method of selling products of all sorts. US advertising rates are determined primarily by Nielsen ratings

Geographical Usage

US networks

In the US, the three original commercial television networks (ABC, CBS, and NBC) provide prime-time programs for their affiliate stations to air from 8pm-11pm Monday-Saturday and 7pm-11pm on Sunday. (7pm to 10pm, 6pm to 10pm respectively in the Central and Mountain time zones). Most stations procure other programming, often syndicated, off prime time. The FOX Network does not provide programming for the last hour of prime time; as a result, many FOX affiliates air a local news program at that time. Three newer broadcasting networks, The WB, PAX, and UPN, also do not provide the same amount of network programming as so-called traditional networks.

Canadian networks

In Canada, there are three national television networks. One, the CBC, is government-owned and controlled. The other two, CTV and Global, are privately-run. The private networks usually rebroadcast U.S. shows, while the CBC sticks to Canadian programming. The CRTC requires all television services in Canada to broadcast a minimum percentage of Canadian production. This proportion is set higher during the prime-time hours.

European networks

In much of Europe television broadcasting has historically been state dominated, rather than commercially organised, although commercial stations have grown in number recently. In the United Kingdom, the major state broadcaster is the BBC (British Broadcasting Corporation), commercial broadcasters include ITV (Independent Television), Channel 4 and Channel 5, as well as the satellite broadcaster British Sky Broadcasting. Other leading European networks include RAI (Italy), TF1 and France Télévisions (France), ARD (Germany), RTÉ (Ireland), TVP (Poland), TVE (Spain) and the largest private European broadcaster RTL Group. Euronews is a pan-European news station, broadcasting both by satellite and terrestrially (timesharing on State TV networks) to most of the continent. Broadcast in several languages (English, French, German, Spanish, Russian, Portuguese and Italian) it draws on contributions from State broadcasters and the ITN news network.

Asian networks and stations

In Asia, television has traditionally been state-controlled, although the number of private stations is increasing, as is competition from satellite television. Japan's NHK is a non-commercial network similar to the BBC, funded by a television licence fee, and has more editorial independence over news and current affairs than broadcasters like India's state-run Doordarshan or China's China Central Television.

Middle East networks and stations

Similarly in the Middle East, television has been heavily state-controlled, with considerable censorship of both news coverage and entertainment, particularly that imported from the West. This control of the medium has been eroded by the increasing availability of satellite TV, and the number of satellite channels in Arabic is second only to the number of satellite channels in English, the best known of which being the Qatar-based news service Al-Jazeera.

African networks and stations

Despite being the most economically advanced country on the continent, South Africa did not introduce TV until 1976, owing to opposition from the apartheid regime. Nigeria was one of the first countries in Africa to introduce television, in 1959, followed by Zimbabwe (then Rhodesia) in 1961, while Zanzibar was the first in Africa to introduce colour television, in 1973. (Tanzania itself did not introduce television until 1994). The main satellite TV providers are the South African Multichoice DStv service, and the predominantly French language Canal Horizons, owned by France's Canal Plus.

(See the list of television stations in Africa.)

Distribution

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

  1. Original Run - a producer creates a program of one or multiple episodes and shows it on a station or network which has either paid for the production itself or to which a license has been granted by the producers to do the same.

  2. Syndication - this is the terminology rather broadly used to describe secondary programming usages (beyond original run.) It includes secondary runs in the country of first issue, but also international usage which may or may not be managed by the originating producer. In many cases other companies, TV stations or individuals are engaged to do the syndication work, in other words to sell the product into the markets they are allowed to sell into by contract from the copyright holders, in most cases the producers. -- 13:49, 7 Jul 2004 (UTC) B. Kelley

Health effects

Excessive TV viewing may cause several mental and somatic deseases, including ADD [1], excessive weight and heart problems [1], diabetes [1] and increased aggression [1]. Doctors generally recommend to limit TV viewing by children to 1-2 hours a day.

Colloquial names

Related articles

External links

Further Reading

TV as social pathogen, opiate, mass mind control, etc


Alternate use of the term:
Television (band)