Digital broadcasting
Encyclopedia
Digital broadcasting is the practice of using digital data rather than analogue waveforms to carry broadcasts over television channels or assigned radio frequency bands. It is becoming increasingly popular for television usage (especially satellite television
Satellite television
Satellite television is television programming delivered by the means of communications satellite and received by an outdoor antenna, usually a parabolic mirror generally referred to as a satellite dish, and as far as household usage is concerned, a satellite receiver either in the form of an...

) but is having a slower adoption rate for radio.

Digital links, thanks to the use of data compression, generally have more efficient bandwidth usage than analog links, which allows a content provider more room to provide services, or to provide a higher-quality signal than had been previously available.

It is estimated that the share of digital broadcasting increased from 7% of the total amount of broadcasted information in 2000, to 25% in 2007.

The premise behind digital broadcasting

NB: For more information on the premise of digital broadcasting refer to the 2002 edition of the World Radio TV Handbook
World Radio TV Handbook
The World Radio TV Handbook, known also with the acronym WRTH, is a directory of virtually every radio and TV station on Earth, published yearly. It began publication in 1947 as the World Radio Handbook...

.

Digital broadcasting has been helped greatly thanks to the presence of computers. In fact, with the invention of the integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

 in the 1960s and the microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...

 in the 1970s, digital broadcasting seems to have taken a footing in the global village that is broadcasting. However, most broadcasters are switching to digital broadcasting mostly because of a lack of frequency space.
  1. In the UK
    United Kingdom
    The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

    , the FM broadcasting
    FM broadcasting
    FM broadcasting is a broadcasting technology pioneered by Edwin Howard Armstrong which uses frequency modulation to provide high-fidelity sound over broadcast radio. The term "FM band" describes the "frequency band in which FM is used for broadcasting"...

     band is extremely limited. It is only possible to fit three BBC
    BBC
    The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...

     services comfortably: BBC Radio 1
    BBC Radio 1
    BBC Radio 1 is a British national radio station operated by the British Broadcasting Corporation which also broadcasts internationally, specialising in current popular music and chart hits throughout the day. Radio 1 provides alternative genres after 7:00pm including electronic dance, hip hop, rock...

    , BBC Radio 2
    BBC Radio 2
    BBC Radio 2 is one of the BBC's national radio stations and the most popular station in the United Kingdom. Much of its daytime playlist-based programming is best described as Adult Contemporary or AOR, although the station is also noted for its specialist broadcasting of other musical genres...

    , and BBC Radio 3
    BBC Radio 3
    BBC Radio 3 is a national radio station operated by the BBC within the United Kingdom. Its output centres on classical music and opera, but jazz, world music, drama, culture and the arts also feature. The station is the world’s most significant commissioner of new music, and its New Generation...

    . In most areas BBC Radio 4
    BBC Radio 4
    BBC Radio 4 is a British domestic radio station, operated and owned by the BBC, that broadcasts a wide variety of spoken-word programmes, including news, drama, comedy, science and history. It replaced the BBC Home Service in 1967. The station controller is currently Gwyneth Williams, and the...

     is also on FM, but for other locations Radio 4 uses AM
    AM broadcasting
    AM broadcasting is the process of radio broadcasting using amplitude modulation. AM was the first method of impressing sound on a radio signal and is still widely used today. Commercial and public AM broadcasting is carried out in the medium wave band world wide, and on long wave and short wave...

     and longwave
    Longwave
    In radio, longwave refers to parts of radio spectrum with relatively long wavelengths. The term is a historic one dating from the early 20th century, when the radio spectrum was considered to consist of long, medium and short wavelengths...

     because of the lack of space on FM. In fact, this is why BBC Radio Five Live
    BBC Radio Five Live
    BBC Radio 5 Live is the BBC's national radio service that specialises in live BBC News, phone-ins, and sports commentaries...

     exclusively uses AM. On the commercial radio front, only Classic FM
    Classic FM (UK)
    Classic FM, one of the United Kingdom's three Independent National Radio stations, broadcasts classical music in a popular and accessible style.-Overview:...

     can comfortably fit in FM: TalkSPORT
    TalkSPORT
    Talksport , owned by UTV radio, is one of the United Kingdom's three terrestrial analogue Independent National Radio broadcasters, offering a sports and talk radio service broadcast from London to the United Kingdom....

     and Virgin Radio
    Virgin Radio
    Absolute Radio is one of the UK's three Independent National Radio stations. The station rebranded to its current name at 7.45am on 29 September 2008.The station is based in London and plays popular rock music...

     use AM. In addition, local radio stations use a mixture of FM and AM. The same can also be said for British television, which exclusively uses the pan-European UHF
    Ultra high frequency
    Ultra-High Frequency designates the ITU Radio frequency range of electromagnetic waves between 300 MHz and 3 GHz , also known as the decimetre band or decimetre wave as the wavelengths range from one to ten decimetres...

     television band after VHF television (PAL
    PAL
    PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...

    -A) was discontinued in the 1980s. Only BBC1, BBC2, ITV1
    ITV1
    ITV1 is a generic brand that is used by twelve franchises of the British ITV Network in the English regions, Wales, southern Scotland , the Isle of Man and the Bailiwicks of Jersey and Guernsey. The ITV1 brand was introduced by Carlton and Granada in 2001, alongside the regional identities of their...

    , and Channel Four could comfortably fit. In addition, Channel Five could broadcast only in a few limited areas because of the strain of the TV band. There are also a few local television stations, but they are mostly low-power and are not affected, if any.
  2. In Canada
    Canada
    Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

    , the Canadian Broadcasting Corporation
    Canadian Broadcasting Corporation
    The Canadian Broadcasting Corporation, commonly known as CBC and officially as CBC/Radio-Canada, is a Canadian crown corporation that serves as the national public radio and television broadcaster...

    /Société Radio-Canada (CBC/Radio-Canada) operates four domestic radio networks: CBC Radio One
    CBC Radio One
    CBC Radio One is the English language news and information radio network of the publicly-owned Canadian Broadcasting Corporation. It is commercial free and offers both local and national programming...

    , CBC Radio 2, Première Chaîne and Espace musique
    Espace musique
    Espace musique is the French-language music radio service of Canada's national public broadcaster, the Canadian Broadcasting Corporation...

    . Originally, Radio One and Première Chaîne used AM and Radio 2 and Espace musique used FM. However, most CBC radio broadcasts use FM now, putting strains on the FM radio band. This has left the AM band almost dry, since most local broadcasters are using FM. However, Canada uses the NTSC
    NTSC
    NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...

     television system used in the US, so there aren't any problems with television, yet.
  3. In South Asia, the Sri Lanka Broadcasting Corporation
    Sri Lanka Broadcasting Corporation
    The Sri Lanka Broadcasting Corporation came into existence on January 5, 1967 when Radio Ceylon became a public corporation. Dudley Senanayake who was the Prime Minister of Ceylon in 1967 ceremonially opened the newly established Ceylon Broadcasting Corporation along with Minister Ranasinghe...

     formerly Radio Ceylon
    Radio Ceylon
    Radio Ceylon is the oldest radio station in Asia. Broadcasting was started on an experimental basis in Ceylon by the Telegraph Department in 1923, just three years after the inauguration of broadcasting in Europe.- Edward Harper :...

    , operates a pioneering FM radio station in Colombo.
  4. In addition, there are inherent problems with AM and FM. FM in particular is prone to multipath interference
    Multipath interference
    Multipath interference is a phenomenon in the physics of waves whereby a wave from a source travels to a detector via two or more paths and, under the right condition, the two components of the wave interfere...

     and the need to constantly retune the radio because of problems with the signal. AM, by contrast, doesn't suffer with multipath but when going under bridges or in tunnels, reception
    Reception
    Reception is a noun form of receiving, or to receive something, such as information, art, experience, or people. It is often used in the following contexts:...

     is absent. AM in particular (as well as LW and SW) is also prone to conditions on the Sun
    Sun
    The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

    . RDS
    Radio Data System
    Radio Data System, or RDS, is a communications protocol standard for embedding small amounts of digital information in conventional FM radio broadcasts. RDS standardises several types of information transmitted, including time, station identification and programme information.Radio Broadcast Data...

    , known in the US as RBRS, has alleviated some of the problems with FM, but hasn't been fully implemented in AM.


Thus, because of these problems, most broadcasters are switching to digital techniques.

Related links

  • Digital radio
    Digital radio
    Digital radio has several meanings:1. Today the most common meaning is digital radio broadcasting technologies, such as the digital audio broadcasting system, also known as Eureka 147. In these systems, the analog audio signal is digitized into zeros and ones, compressed using formats such as...

  • Digital television
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    Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...

  • ATSC Standards
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    ATSC tuner
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  • Digital Audio Broadcasting
    Digital audio broadcasting
    Digital Audio Broadcasting is a digital radio technology for broadcasting radio stations, used in several countries, particularly in Europe. As of 2006, approximately 1,000 stations worldwide broadcast in the DAB format....

  • Digital Radio Mondiale
    Digital Radio Mondiale
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  • Digital Video Broadcasting
  • HD Radio
    HD Radio
    HD Radio, which originally stood for "Hybrid Digital", is the trademark for iBiquity's in-band on-channel digital radio technology used by AM and FM radio stations to transmit audio and data via a digital signal in conjunction with their analog signals...

  • Satellite radio
    Satellite radio
    Satellite radio is an analogue or digital radio signal that is relayed through one or more satellites and thus can be received in a much wider geographical area than terrestrial FM radio stations...

  • Satellite television
    Satellite television
    Satellite television is television programming delivered by the means of communications satellite and received by an outdoor antenna, usually a parabolic mirror generally referred to as a satellite dish, and as far as household usage is concerned, a satellite receiver either in the form of an...

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