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 televisual has become synonymous with postmodern culture. The word television is a hybridword, coming from both Greek and Latin. "Tele-" is Greek for "far", while "-vision" is from the Latin "visio", meaning "vision" or "sight".
Paul Gottlieb Nipkow proposed and patented the first electromechanical television system in 1884. However, some trace line-by-line image scanning technology and concepts to fax machines, which pre-date television technology.
In 1932 the BBC launched a service using Baird's 30-line system and these transmissions continued until 11th September1935. 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.
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.
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 manufacturingtechnology 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. ATSCHDTV 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.
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.
, modern television sets diverged into three different trends:
standalone TV sets;
integrated systems with DVD players and/or VHSVCR capabilities built into the TV set itself (mostly for small size TVs with up to 17" screen, the main idea is to have a complete portable system);
component systems with separate big-screen video monitor, tuner, audio system which the owner connects the pieces together as a high-end home theater system. This approach appeals to videophiles that prefer components that can be upgraded separately.
There are many kinds of video monitors used in modern TV sets. The most common are direct view CRTs 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 matrixLCD 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 brandedMSN TV).
Even for simple video, there are five standard ways to connect a device. These are as follows:
Component video - three separate connectors, with one brightness channel and two color channels (hue and saturation), and is usually referred to as "Y, B-Y, R-Y", "Y Pr Pb", or YUV. This provides for high quality pictures and is usually used inside professional studios. However, it is being used more in home theater for DVDs and high-end sources. Audio is not carried on this cable.
SCART - A large 21 pin connector that may carry composite video, S-Video or, for better quality, separate red, green and blue (RGB) signals and two-channel sound, along with a number of control signals. This system is standard in Europe but rarely found elsewhere.