22-inch flat screen CRT television.
(
TV) is a widely used
telecommunication medium for transmitting and receiving moving
images, either
monochromatic ("black and white") or
color, usually accompanied by
sound. "Television" may also refer specifically to a
television set,
television programming or
television transmission. The word is derived from mixed
Latin and
Greek roots, meaning "far sight": Greek
tele (), far, and Latin
visio, sight (from
video, vis- to see, or to view in the first person).
Commercially available since the late 1930s, the television set has become a common communications receiver in homes, businesses and institutions, particularly as a source of
entertainment and news. Since the 1970s the availability of
video cassettes,
laserdiscs,
DVDs and now
Blu-ray Discs, have resulted in the television set frequently being used for viewing recorded as well as broadcast material.
Although other forms such as
closed-circuit television are in use, the most common usage of the medium is for
broadcast television, which was modeled on the existing
radio broadcasting systems developed in the 1920s, and uses high-powered
radio-frequency transmitters to
broadcast the television signal to individual TV receivers.
Broadcast TV is typically disseminated via
radio transmissions on designated channels in the 54–890
megahertz frequency band. Signals are now often transmitted with
stereo and/or
surround sound in many countries. Until the 2000s broadcast TV programs were generally recorded and transmitted as an
analog signal, but in recent years public and commercial broadcasters have been progressively introducing
digital television broadcasting technology.
A standard television set comprises multiple internal
electronic circuits, including those for
receiving and decoding
broadcast signals. A visual
display device which lacks a tuner is properly called a
monitor, rather than a television. A television system may use different technical standards such as
digital television (DTV) and
high-definition television (HDTV). Television systems are also used for surveillance, industrial process control, and guiding of weapons, in places where direct observation is difficult or dangerous.
Amateur television (
ham TV or
ATV) is also used for experimentation, pleasure and public service events by
amateur radio operators. Ham TV stations were on the air in many cities before commercial TV stations came on the air.
History
thumb|right|[[BBC Broadcasting House. The
BBC is the largest and oldest broadcaster in the world.]]
In its early stages of development, television employed a combination of
optical, mechanical and
electronic technologies to capture, transmit and display a visual image. By the late 1920s, however, those employing only optical and electronic technologies were being explored. All modern television systems rely on the latter, although the knowledge gained from the work on mechanical-dependent systems was crucial in the development of fully electronic television.
The first time images were transmitted electrically were via early mechanical
fax machines, including the
pantelegraph, developed in the late 1800s. The concept of electrically-powered transmission of television images in motion, was first sketched in 1878 as the
telephonoscope, shortly after the invention of the
telephone. At the time, it was imagined by early science fiction authors, that someday that
light could be transmitted over wires, as sounds were.
The idea of using
scanning to transmit images was put to actual practical use in 1881 in the pantelegraph, through the use of a
pendulum-based scanning mechanism. From this period forward, scanning in one form or another, has been used in nearly every image transmission technology to date, including television. This is the concept of "
rasterization", the process of converting a visual image into a stream of electrical pulses.
In 1884
Paul Gottlieb Nipkow, a 20-year old university student in Germany, patented the first electromechanical television system which employed a
scanning disk, a spinning disk with a series of holes spiraling toward the center, for rasterization. The holes were spaced at equal
angular intervals such that in a single rotation the disk would allow light to pass through each hole and onto a light-sensitive
selenium sensor which produced the electrical pulses. As an image was focused on the rotating disk, each hole captured a horizontal "slice" of the whole image, in a scanning fashion.
Nipkow's design would not be practical until advances in
amplifier tube technology became available in 1907. Even then the device was only useful for transmitting still "
halftone" images - represented by equally spaced dots of varying size - over telegraph or
telephone lines. Later designs would use a rotating mirror-drum scanner to capture the image and a
cathode ray tube (CRT) as a display device, but moving images were still not possible, due to the poor sensitivity of the
selenium sensors.
Scottish inventor
John Logie Baird demonstrated the transmission of moving silhouette images in
London in 1925, and of moving,
monochromatic images in 1926. Baird's scanning disk produced an image of 30 lines resolution, just enough to discern a human face, from a double spiral of
lenses.. Remarkably, in 1927 Baird also invented the world's first
video recording system, "Phonovision" -- by modulating the output signal of his
TV camera down to the audio range he was able to capture the signal on a 10-inch wax audio disc using conventional audio recording technology. A handful of Baird's 'Phonovision' recordings survive and these were finally decoded and rendered into viewable images in the 1990s using modern digital signal-processing technology.
In 1926,
Hungarian engineer
Kálmán Tihanyi designed a television system utilizing fully electronic scanning and display elements, and employing the principle of "charge storage" within the scanning (or "camera") tube.
[United States Patent Office, Patent No. 2,133,123, Oct. 11, 1938.][United States Patent Office, Patent No. 2,158,259, May 16, 1939]By 1927, Russian inventor
Léon Theremin developed a mirror drum-based television system which used
interlacing to achieve an
image resolution of 100 lines.
Also in 1927,
Herbert E. Ives of
Bell Labs transmitted moving images from a 50-
aperture disk producing 16 frames per minute over a
cable from
Washington, DC to
New York City, and via
radio from
Whippany, New Jersey. Ives used viewing screens as large as 24 by 30 inches (60 by 75
centimeters). His subjects included
Secretary of Commerce Herbert Hoover.
In 1927,
Philo Farnsworth made the world's first working television system with electronic scanning of both the pickup and display devices,
[, The Virtual Museum of the City of San Francisco] which he first demonstrated to the press on 1 September 1928.
[Farnsworth, Elma G., Distant Vision: Romance and Discovery on an Invisible Frontier, Salt Lake City, PemberlyKent, 1989, p. 108.]The first practical use of television was in Germany. Regular television broadcasts began in Germany in 1929 and in 1936 the
Olympic Games in Berlin were broadcast to television stations in Berlin and Leipzig where the public could view the games live.
In 1936,
Kálmán Tihanyi described the principle of
plasma television, the first flat panel system.
Geographical usage
Television introduction by country
Content
Programming
Getting TV programming shown to the public can happen in many different ways. After production the next step is to market and deliver the product to whatever markets are open to using it. This typically happens on two levels:
- Original Run or First Run: a producer creates a program of one or multiple episodes and shows it on a station or network which has either paid for the production itself or to which a license has been granted by the producers to do the same.
- 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 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.
First run programming is increasing on subscription services outside the U.S., but few domestically produced programs are syndicated on domestic
free-to-air (FTA) elsewhere. This practice is increasing however, generally on digital-only FTA channels, or with subscriber-only first run material appearing on FTA.
Unlike the U.S., repeat FTA screenings of a FTA network program almost only occur on that network. Also,
affiliates rarely buy or produce non-network programming that is not centred around local events.
Funding
Television sets per 1000 people of the world
Around the globe, broadcast television is financed by either government, advertising, licensing (a form of tax), subscription or any combination of these. To protect revenues, subscription TV channels are usually encrypted to ensure that only subscription payers receive the decryption codes to see the signal. Non-encrypted channels are known as
free to air or
FTA.
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") in order to fund their programming.
United States
Since inception in the U.S. in 1940,
TV commercials have become one of the most effective, persuasive, and popular method of selling products of many sorts, especially consumer goods. U.S.
advertising rates are determined primarily by
Nielsen Ratings. The time of the day and popularity of the channel determine how much a television commercial can cost. For example, the highly popular
American Idol can cost approximately $750,000 for a thirty second block of commercial time; while the same amount of time for the
World Cup and the
Super Bowl can cost several million dollars.
In recent years, the paid program or
infomercial has become common, usually in lengths of 30 minutes or one hour. Some
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 TV programs also weave advertisements into their shows, a practice begun in film and known as
product placement. For example, a character could be drinking a certain kind of soda, going to a particular
chain restaurant, or driving a certain make of car. (This is sometimes very subtle, where shows have vehicles provided by manufacturers for low cost, rather than wrangling them.) Sometimes a specific brand or
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,
Lew Grade, likened the broadcasting licence as being a "licence to print money". Restrictions mean that the big three national commercial TV channels:
ITV,
Channel 4, and
Five 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 US have unnatural breaks where the UK company has edited out the breaks intended for US 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 program, documentaries, and programs for children. Nor may advertisements be carried in a program designed and broadcast for reception in schools or in any religious 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, being strictly
non-commercial is not allowed to show advertisements on television in the UK, although it has many advertising-funded channels abroad. The majority of its budget comes from TV licencing (see below) and the sale of content to other broadcasters.
Republic of Ireland
The
Broadcasting Commission of Ireland (
BCI) () oversees advertising on television and radio within the
Republic of Ireland on both private and state owned broadcasters. Similar to other European countries, advertising is found on both private and state owned broadcasters. There are some restrictions based on advertising, especially in relation to the advertising of alcohol. Such advertisements are prohibited until after 7pm. Broadcasters in the
Republic of Ireland adhere to broadcasting legislation implemented by the
Broadcasting Commission of Ireland and the
European Union. Sponsorship of current affairs programming is prohibited at all times.
As of October 1, 2009 the responsibilities held by the BCI are gradually being transferred to the
Broadcasting Authority of Ireland.
Taxation or license
Television services in some countries may be funded by a
television licence, a form of taxation which means 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:
The
BBC carries no advertising on its UK channels and is funded by an annual licence paid by all households owning a television. This licence fee is set by government, but the BBC is not answerable to or controlled by government and is therefore genuinely independent.
The two main BBC TV channels are watched by almost 90 percent of the population each week and overall have 27 per cent share of total viewing. This in spite of the fact that 85% of homes are multichannel, 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. The licence that funds the seven advertising-free BBC TV channels currently costs £139.50 a year (about US$215) irrespective of the number of TV sets owned. When the same sporting event has been presented on both BBC and commercial channels, the BBC always attracts the lion's share of the audience, indicating viewers prefer to watch TV uninterrupted by advertising.
The
Australian Broadcasting Corporation (ABC) carries no advertising (except for the ABC Shop) as it is banned under law . The ABC receives its funding from the Australian Government every three years. In the 2006/07 Federal Budget the ABC received Au$822.67 Million this covers most of the ABC funding commitments and, as with the BBC, also funds radio channels, transmitters and the ABC web sites. The ABC also receives funds from its many ABC Shops across Australia.
In
France and the
Republic of Ireland government-funded channels carry advertisements yet those who own television sets have to pay an annual tax ("la redevance audiovisuelle").
Subscription
Some TV channels are partly funded from subscriptions and therefore the signals are encrypted during broadcast to ensure that only paying subscribers have access to the decryption codes. Most subscription services are also funded by advertising.
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 drama and dramatic miniseries. However, other genres, such as historical Western genres, may also have high production costs.
Popular 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.
Science fiction shows 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 shows for the adult demographic such as
Family Guy.
The least expensive forms of entertainment programming are
game shows,
talk shows,
variety shows, and
reality TV. Game shows show contestants answering questions and solving puzzles to win prizes. Talk shows feature interviews with film, television and music 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 TV shows "regular" people (
i.e., not
actors) who are facing unusual challenges or experiences, ranging from arrest by police officers (
COPS) to weight loss (
The Biggest Loser). A variant version of reality shows depicts celebrities doing mundane activities such as going about their everyday life (
Snoop Dogg's Father Hood) or doing manual labour (
Simple Life).
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
media violence research.
Environmental aspects
With high
lead content in
CRTs, and the rapid diffusion of new, flat-panel display technologies, some of which (
LCDs) use lamps containing
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.
In numismatics
Television has had such an impact in today's life, that it has been the main motif for numerous collectors' coins and medals. One of the most recent ones is the
Euro gold and silver commemorative coins (Austria) minted in March 9, 2005. The obverse of the coin shows a "
test pattern", while the reverse shows several milestones in the history of television.
See also
