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Broadcasting is the distribution of audio and/or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum (radio waves), in a one-to-many model.
Broadcasting began with AM radio broadcasting which sprang up spontaneously around 1920. Before this, all forms of electronic communication, radio, telephone, and telegraph, were “one-to-one”, with the message intended for a single recipient.
The term “broadcasting”, borrowed from the agricultural method of sowing seeds in a field by casting them broadly about, was coined by either KDKA manager Frank Conrad or RCA historian George Clark around 1920 to distinguish this new activity of “one-to-many” communication; a single radio station transmitting to multiple listeners.
Over the air Broadcasting is usually associated with radio and television, though in practice radio and television transmissions take place using both wires and radio waves. The receiving parties may include the general public or a relatively small subset; the point is that anyone with the appropriate receiving technology can receive the signal.
U.S. Code of Federal Regulations, title 47, part 97 defines “broadcasting” as “transmissions intended for reception by the general public, either direct or relayed”. Private or two-way telecommunications transmissions do not qualify under this definition.
Transmission of radio and television programs from a radio or television station to home receivers over the spectrum is referred to as OTA (over the air) or terrestrial broadcasting and in most countries requires a broadcasting license. Transmissions using a combination of satellite and wired transmission, like cable television (which also retransmits OTA stations with their consent), are also considered broadcasts, and do not require a license. Transmissions of television and radio via streaming digital technology have increasingly been referred to as broadcasting as well, though strictly speaking this is incorrect.
The earliest broadcasting consisted of sending telegraph signals over the airwaves, using Morse code. This was particularly important for ship-to-ship and ship-to-shore communication, but it became increasingly important for business and general news reporting, and as an arena for personal communication by radio amateurs (Douglas, op. cit.).
Audio broadcasting began experimentally in the first decade of the 20th century. By the early 1920s radio broadcasting became a household medium, at first on the AM band and later on FM.
Television broadcasting started experimentally in the 1920s and became widespread after World War II, using VHF and UHF spectrum.
Satellite broadcasting was initiated in the 1960s and moved into general industry usage in the 1970s, with DBS (Direct Broadcast Satellites) emerging in the 1980s.
Originally all broadcasting was composed of analog signals using analog transmission techniques but more recently broadcasters have switched to digital signals using digital transmission.
In general usage, broadcasting most frequently refers to the transmission of information and entertainment programming from various sources to the general public.
Methods of Broadcasting
Historically, there have been several methods used for broadcasting electronic media audio and/or video to the general public:
• Telephone broadcasting (1881–1932): the earliest form of electronic broadcasting (not counting data services offered by stock telegraph companies from 1867, if ticker-tapes are excluded from the definition). Telephone broadcasting began with the advent of Théâtrophone (“Theatre Phone”) systems, which were telephone-based distribution systems allowing subscribers to listen to live opera and theatre performances over telephone lines, created by French inventor Clément Ader in 1881. Telephone broadcasting also grew to include telephone newspaper services for news and entertainment programming which were introduced in the 1890s, primarily located in large European cities. These telephone-based subscription services were the first examples of electrical/electronic broadcasting and offered a wide variety of programming.
• Radio broadcasting (experimentally from 1906, commercially from 1920); audio signals sent through the air as radio waves from a transmitter, picked up by an antenna and sent to a receiver. Radio stations can be linked in radio networks to broadcast common radio programs, either in broadcast syndication, simulcast or subchannels.
• Television broadcasting (telecast), experimentally from 1925, commercially from the 1930s: an extension of radio to include video signals.
• Cable radio (also called “cable FM”, from 1928) and cable television (from 1932): both via coaxial cable, originally serving principally as transmission media for programming produced at either radio or television stations, but later expanding into a broad universe of cable-originated channels.
• Direct-broadcast satellite (DBS) (from circa 1974) and satellite radio (from circa 1990): meant for direct-to-home broadcast programming (as opposed to studio network uplinks and downlinks), provides a mix of traditional radio or television broadcast programming, or both, with dedicated satellite radio programming.
• Webcasting of video/television (from circa 1993) and audio/radio (from circa 1994) streams: offers a mix of traditional radio and television station broadcast programming with dedicated internet radio.
There are several means of providing financial support for continuous broadcasting:
• Commercial broadcasting: for-profit, usually privately owned stations, channels, networks, or services providing programming to the public, supported by the sale of time to advertisers for radio or television advertisements during or in breaks between programs, often in combination with cable or pay cable subscription fees.
• Public broadcasting: usually non-profit, publicly owned stations or networks supported by license fees, government funds, grants from foundations, corporate underwriting, and audience memberships and/or contributions, or a combination of these.
• Community broadcasting: is designed to fulfil social and cultural needs by allowing members of the audience to participate in decisions about programming and, in the case of radio, in the ownership of stations. It serves local communities, reflecting the diversity of their views and needs, and provides access to volunteer participants.
Recorded broadcasts and live broadcasts
The first regular television broadcasts started in 1937.
Broadcasts can be classified as “recorded” or “live”. The former allows correcting errors, and removing superfluous or undesired material, rearranging it, applying slow motion and repetitions, and other techniques to enhance the program. However, some live events like sports television can include some of the aspects including slow motion clips of important goals/hits, etc., in between the live television telecast.
A disadvantage of recording first is that the public may know the outcome of an event from another source, which may be a “spoiler”. In addition, prerecording prevents live radio announcers from deviating from an officially approved script.
Many events are advertised as being live, although they are often “recorded live” (sometimes called “live-to-tape”). This is particularly true of performances of musical artists on radio when they visit for an in-studio concert performance. Similar situations have occurred in television production and news broadcasting.
A broadcast may be distributed through several physical means. If coming directly from the radio studio at a single station or television station, it is simply sent through the studio/transmitter link to the transmitter and hence from the television antenna located on the radio masts and towers out to the world. Programming may also come through a communications satellite, played either live or recorded for later transmission. Networks of stations may simulcast the same programming at the same time, originally via microwave link, now usually by satellite.
Distribution to stations or networks may also be through physical media, such as magnetic tape, compact disc (CD), DVD, and sometimes other formats. Usually these are included in another broadcast, such as when electronic news gathering (ENG) returns a story to the station for inclusion on a news programme.
The final leg of broadcast distribution is how the signal gets to the listener or viewer. It may come over the air as with a radio station or television station to an antenna and radio receiver, or may come through cable television or cable radio (or “wireless cable”) via the station or directly from a network. The Internet may also bring either internet radio or streaming media television to the recipient, especially with multicasting allowing the signal and bandwidth to be shared.
The term “broadcast network” is often used to distinguish networks that broadcast an over-the-air television signals that can be received using a tuner (television) inside a television set with a television antenna from so-called networks that are broadcast only via cable television (cablecast) or satellite television that uses a dish antenna. The term “broadcast television” can refer to the television programs of such networks.
Our Source: http://bit.ly/broadcastinghistory