Cable television or Community Antenna Television (CATV)
(often shortened to cable) is a system of providing television, FM radio programming and other services to consumers via radio frequency signals transmitted directly to people’s televisions through fixed optical fibers or coaxial cables as opposed to the over-the-air method used in traditional television broadcasting (via radio waves) in which a television antenna is required.
It is most commonplace in North America, Europe, Australia and East Asia, though it is present in many other countries, mainly in South America and the Middle East. Cable TV has had little success in Africa, as it is not cost-effective to lay cables in sparsely populated areas, and although so-called "wireless cable" or microwave-based systems are used, "direct-to-home" satellite television is far more popular, especially in South Africa.
Cable TV and CATV
Technically, both cable TV and CATV involve distributing a number of television channels collected at a central location (called a headend) to subscribers within a community by means of a network of optical fibers and/or coaxial cables and broadband amplifiers.
As in the case of radio broadcasting, the use of different frequencies allows many channels to be distributed through the same cable, without separate wires for each. The tuner of the TV, VCR or radio selects one channel from this mixed signal.
The same program is often simultaneously broadcast by radio and distributed by cable, usually at different frequencies. Other programs may be distributed by cable only; rules restricting content (e.g. regarding nudity and pornography) are often more relaxed for cable than for over-the-air TV.
Traditional cable TV systems worked strictly by way of analog signals (i.e. using standard radio waves) but many modern cable TV systems also employ the use of digital cable technology, which uses compressed digital signals, allowing them to provide many more channels than they could with analog alone.
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