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Digital radio

January 01, 1970

Not to be confused with Internet radio.
"Digital audio broadcasting" redirects here. For the specific technical standard, see Digital Audio Broadcasting.

Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services.

Types edit

In digital broadcasting systems, the analog audio signal is digitized, compressed using an audio coding format such as AAC+ (MDCT)[1] or MP2, and transmitted using a digital modulation scheme. The aim is to increase the number of radio programs in a given spectrum, to improve the audio quality, to eliminate fading problems in mobile environments, to allow additional datacasting services, and to decrease the transmission power or the number of transmitters required to cover a region. However, analog radio (AM and FM) is still more popular and listening to radio over IP (Internet Protocol) is growing in popularity.

In 2012 four digital wireless radio systems are recognized by the International Telecommunication Union: the two European systems Digital Audio Broadcasting (DAB) and Digital Radio Mondiale (DRM), the Japanese ISDB-T and the in-band on-channel technique used in the US and Arab world and branded as HD Radio.

An older definition, still used in communication engineering literature, is wireless digital transmission technologies, i.e. microwave and radio frequency communication standards where analog information signals as well as digital data are carried by a digital signal, by means of a digital modulation method. This definition includes broadcasting systems such as digital TV and digital radio broadcasting, but also two-way digital radio standards such as the second generation (2G) cell-phones and later, short-range communication such as digital cordless phones, wireless computer networks, digital micro-wave radio links, deep space communication systems such as communications to and from the two Voyager space probes, etc.

A less common definition is radio receiver and transmitter implementations that are based on digital signal processing, but may transmit or receive analog radio transmission standards, for example FM radio. This may reduce noise and distortion induced in the electronics. It also allows software radio implementations, where the transmission technology is changed just by selecting another piece of software. In most cases, this would however increase the energy consumption of the receiver equipment[citation needed].

One-way (broadcasting) systems edit

Broadcast standards edit

Digital audio radio service standards may provide terrestrial or satellite radio service. Digital radio broadcasting systems are typically designed for handheld mobile devices, like mobile-TV systems and unlike other digital TV systems which typically require a fixed directional antenna. Some digital radio systems provide in-band on-channel (IBOC) solutions that may coexist with or simulcast with analog AM or FM transmissions, while others are designed for designated radio frequency bands. The latter allows one wideband radio signal to carry a multiplex of several radio-channels of various bitrates as well as data services and other forms of media. Some digital broadcasting systems allow single-frequency network (SFN), where all terrestrial transmitters in a region sending the same multiplex of radio programs may use the same frequency channel without self-interference problems, further improving the system spectral efficiency.

While digital broadcasting offers many potential benefits, its introduction has been hindered by a lack of global agreement on standards and many disadvantages. The DAB Eureka 147 standard for digital radio is coordinated by the World DMB Forum. This standard of digital radio technology was defined in the late 1980s, and is now being introduced in some European countries. Commercial DAB receivers began to be sold in 1999 and, by 2006, 500 million people were in the coverage area of DAB broadcasts, although by this time sales had only taken off in the UK and Denmark. In 2006 there are approximately 1,000 DAB stations in operation.[2] There have been criticisms of the Eureka 147 standard and so a new 'DAB+' standard has been introduced.

The DRM standard has been used for several years to broadcast digitally on frequencies below 30 MHz (shortwave, mediumwave and longwave). Also there is now the extended standard DRM+, which is designed for VHF bands.[3] Tests of DRM+ has been made in countries such as in Brazil, Germany, France, India, Sri Lanka, the UK, Slovakia, Italy (incl. the Vatican), as well as Sweden.[4]

DRM+ is regarded [by whom?] as a more transparent and less costly standard than DAB+ and thus a better choice for local radio [citation needed]; commercial or community broadcasters. Although DAB+ has been introduced in Australia the government concluded in 2011 that a preference for DRM and DRM+ above HD Radio could be used to supplement DAB+ services in (some) local and regional areas. [citation needed]

To date the following standards have been defined for one-way digital radio:

Digital audio broadcasting systems edit

Digital television (DTV) broadcasting systems edit

See also software radio for a discussion of radios which use digital signal processing.

Status by country edit

DAB adopters edit

Further information: Countries using DAB/DMB

Digital Audio Broadcasting (DAB), also known as Eureka 147, has been adopted by around 20 countries worldwide. It is based on the MPEG-1 Audio Layer II audio coding format and this has been co-ordinated by the WorldDMB.

WorldDMB announced in November 2006 that DAB would be adopting the HE-AACv2 audio coding format, also known as eAAC+. Also being adopted are the MPEG Surround format, and stronger error correction coding called Reed–Solomon coding.[5] The update has been named DAB+. Receivers that support the new DAB standard began being released during 2007 with firmware updated available for some older receivers.

DAB and DAB+ cannot be used for mobile TV because they do not include any video codecs. DAB related standards Digital Multimedia Broadcasting (DMB) and DAB-IP are suitable for mobile radio and TV both because they have MPEG 4 AVC and WMV9 respectively as video coding formats. However a DMB video sub-channel can easily be added to any DAB transmission - as DMB was designed from the outset to be carried on a DAB subchannel. DMB broadcasts in Korea carry conventional MPEG 1 Layer II DAB audio services alongside their DMB video services.

United States edit

The United States has opted for the proprietary HD Radio technology, a type of in-band on-channel (IBOC) technology. According to iBiquity, "HD Radio" is the company's trade name for its proprietary digital radio system, but the name does not imply either high definition or "hybrid digital" as it is commonly incorrectly referenced.

Transmissions use orthogonal frequency-division multiplexing, a technique which is also used for European terrestrial digital TV broadcast (DVB-T). HD Radio technology was developed and is licensed by iBiquity Digital Corporation. It is widely believed[by whom?] that a major reason for HD radio technology is to offer some limited digital radio services while preserving the relative "stick values" of the stations involved and to ensure that new programming services will be controlled by existing licensees.

The FM digital schemes in the U.S. provide audio at rates from 96 to 128 kilobits per second (kbit/s), with auxiliary "subcarrier" transmissions at up to 64 kbit/s. The AM digital schemes have data rates of about 48 kbit/s, with auxiliary services provided at a much lower data rate. Both the FM and AM schemes use lossy compression techniques to make the best use of the limited bandwidth.

Lucent Digital Radio, USA Digital Radio (USADR), and Digital Radio Express commenced tests in 1999 of their various schemes for digital broadcast, with the expectation that they would report their results to the National Radio Systems Committee (NRSC) in December 1999.[6] Results of these tests remain unclear, which in general describes the status of the terrestrial digital radio broadcasting effort in North America.

While traditional terrestrial radio broadcasters are trying to "go digital", most major US automobile manufacturers are promoting digital satellite radio. HD Radio technology has also made inroads in the automotive sector with factory-installed options announced by BMW, Ford, Hyundai, Jaguar, Lincoln, Mercedes, MINI, and Volvo.[7]

Satellite radio is distinguished by its freedom from FCC censorship in the United States, its relative lack of advertising, and its ability to allow people on the road to listen to the same stations at any location in the country. Listeners must currently pay an annual or monthly subscription fee in order to access the service.

Sirius Satellite Radio launched a constellation of three Sirius satellites during the course of 2000. The satellites were built by Space Systems/Loral and were launched by Russian Proton boosters. As with XM Satellite Radio, Sirius implemented a series of terrestrial ground repeaters where satellite signal would otherwise be blocked by large structures including natural structures and high-rise buildings.

XM Satellite Radio has a constellation of three satellites, two of which were launched in the spring of 2001, with one following later in 2005. The satellites are Boeing 702 comsats, and were put into orbit by Sea Launch boosters. Back-up ground transmitters (repeaters) will be built in cities where satellite signals could be blocked by big buildings.

On February 19, 2007, Sirius Satellite Radio and XM Satellite Radio merged, to form Sirius XM Radio.

The FCC has auctioned bandwidth allocations for satellite broadcast in the S band range, around 2.3 GHz.

Terrestrial broadcasting has advantages in being free and local. Satellite radio is neither of these things; however, in the early 21st century it has grown by providing uncensored content (most notably, the crossover of Howard Stern from terrestrial radio to satellite radio) and commercial-free, all-digital music channels that offer similar radio formats to local stations.

The "HD Radio" signal of an FM broadcast station in the US has a limited listening distance from the broadcast tower site. FCC regulations currently limit the power of the digital part of the station's transmission to 10% of the existing analog power permitted the station. Even at this power level, the presence of the digital signal right next to the station's analog signal can result in older radios picking up noise due to trouble rejecting the adjacent digital signal. "There are still some concerns that HD Radio on FM will increase interference between different stations even though HD Radio at the 10% power level fits within the FCC spectral mask." HD Radio HD Radio#cite note-14.

"HD Radio" allows each existing broadcast station to add additional "channels" in the US by transmitting a digital signal on both sides of its channel, just beyond their existing analog Frequency Modulation signal. The HD Radio signal occupies the 0.1 MHz that begins 0.1 MHz above and below the carrier frequency station. For instance, if a station's analog signal's carrier frequency is 93.3 MHz, the digital signal will fill 93.1–93.2 MHz and 93.4–93.5 MHz within the FM Broadcast Band. Several digital audio streams, or "subchannels", can be carried within this single digital data stream, with the number of audio of subchannels and bandwidth allocations at the choice of the station. On the radio tuner, these will appear as (in the above case) "93.3-2", "93.3-3", and so on. The frequencies that are used do not change as more channels are added to the one radio station (93.3 MHz in the example above). Instead, a fixed total amount of bandwidth is simply reallocated across the audio streams such that each now receives less bandwidth, and therefore lower audio quality, than before.

There is no federally mandated transition to HD Radio for both FM and AM Stations. However, on October 27, 2020, the FCC approved voluntary all-digital AM operation nationwide.[8]

Canada edit

Canada has begun allowing experimental HD Radio broadcasts in December 2012 and digital audio subchannels on a case-by-case basis, with the first stations in the country being CFRM-FM in Little Current, CING-FM in Hamilton, and CJSA-FM in Toronto (with a fourth, CFMS-FM in the Toronto suburb of Markham applying to operate HD Radio technology), all within the province of Ontario.[9][10]

United Kingdom edit

Main article: Digital radio in the United Kingdom

In the United Kingdom, 44.3% of the population now has a DAB digital radio set and 34.4% of listening is to different digital platforms. Because of the early success of the old DAB standard, the transition to the more efficient DAB+ takes more time. If DAB was switched off, older receivers would become worthless. In 2020, about half of the stations in the UK use DAB+.

26 million people, or 39.6% of the population of 65.64 million, now tune into digital radio each week, up 2.6 million year on year, according to RAJAR in Q1 2013. But FM listening has increased to 61% and DAB decreased to 21% DAB listeners may also use AM & FM too.[11]

The UK currently has the world's biggest digital radio network, with about 500 transmitters, two nationwide DAB ensembles and 48 local and regional DAB ensembles, broadcasting over 250 commercial and 34 BBC radio stations; about 100 stations can be received in London. On DAB digital radio most listeners can receive around 30 additional stations.

Digital radio stations are also distributed on digital television platforms such as Sky, Virgin Media and Freeview, as well as internet radio.

The Government will make a decision on a radio switchover subject to listening and coverage criteria being met. A digital radio switchover would maintain FM as a platform, while moving some services to DAB-only distribution.

DAB+ devices in the UK has been available to the public by 2010

Germany edit

In 2020, DAB+ signals cover more than 90% of Germany. A national multiplex contains three public stations by Deutschlandfunk and 12 commercial stations. In most areas, additional multiplexes with public broadcasters and regional commercial stations are available.

The first DAB station network was deployed in Bavaria since 17 October 1995 until full coverage in 1999. Other states had funded a station network but the lack of success led them to scrap the funding - the MDR switched off in 1998 already and Brandenburg declared a failure in 2004. Instead Berlin/Brandenburg began to switch to digital radio based on an audio-only DVB-T mode given the success of the DVB-T standard in the region when earlier analogue television was switched off in August 2003 (being the first region to switch in Germany). During that time the DVB-H variant of the DVB family was released for transmission to mobile receivers in 2004. During 2005 most radio stations left the DAB network with only one public service broadcaster ensemble to remain in the now fully state-funded station network. At last the KEF [de] (commission to determine the financial needs of broadcasters) blocked federal funding on 15. July 2009 until economic viability of DAB broadcasting would be proven - and pointing to DVB-T as a viable alternative.

Digital radio deployment was rebooted during 2011 - a joint commission of public and private radio broadcasters decided upon "DAB+" as the new national standard in December 2010. The new station network started as planned on 1. August 2011 with 27 stations with 10 kW each giving a coverage of 70% across the nation. A single "Bundesmux" ("fed-mux": short for "federal multiplex") was created on band 5C as a single-frequency network on channel 5C (see [1]). With the initial market success of DAB+ the contractors decided on an expansion of the digital radio station network in November 2012.

Norway edit

Norway was the first country where analog FM radio was switched off in 2017 being replaced by nationwide DAB+ distribution.

Local stations can continue broadcasting in FM.

Other European Countries edit

With DAB being available across Belgium, Netherlands, Switzerland, Denmark, Norway and Northern Italy there is good coverage across the European Backbone area (see countries using DAB/DMB) indicating a sufficient momentum on the market. France, Spain, Sweden and Poland use DAB+ only in the big cities.

Portugal and Finland abandoned DAB. Finland is requesting the EU to mandate that automakers support FM similarly to DAB.

Australia edit

Australia commenced regular digital audio broadcasting using the DAB+ standard on 4 May 2009,[12] after many years of trialling alternative systems. Normal radio services operate on the AM and FM bands, as well as four stations (ABC and SBS) on digital TV channels. The services are currently operating in the five state capital cities: Adelaide, Brisbane, Melbourne, Perth and Sydney, and is being trialled in Canberra and Darwin.[13]

Japan edit

Japan has started terrestrial sound broadcasting using ISDB-Tsb and MobaHO! 2.6 GHz Satellite Sound digital broadcasting

Korea edit

On 1 December 2005 South Korea launched its T-DMB service which includes both television and radio stations. T-DMB is a derivative of DAB with specifications published by ETSI. More than 110,000 receivers had been sold in one month only in 2005.

Hong Kong edit

Hong Kong replaced DAB with DVB-T2 Lite.

Developing nations edit

Digital radio is now being provided to the developing world. A satellite communications company named WorldSpace was setting up a network of three satellites, including "AfriStar", "AsiaStar", and "AmeriStar", to provide digital audio information services to Africa, Asia, and Latin America. AfriStar and AsiaStar are in orbit. AmeriStar cannot be launched from the United States as Worldspace transmits on the L-band and would interfere with USA military as mentioned above.[citation needed]. in its heyday provided service to over 170,000 subscribers in eastern and southern Africa, the Middle East, and much of Asia with 96% coming from India. Timbre Media along with Saregama India plan to relaunch the company. As of 2013 Worldspace is defunct, but two satellites are in orbit which still have a few channels. See main WorldSpace article.

Each satellite provides three transmission beams that can support 50 channels each, carrying news, music, entertainment, and education, and including a computer multimedia service. Local, regional, and international broadcasters were working with WorldStar to provide services.

A consortium of broadcasters and equipment manufacturers are also working to bring the benefits of digital broadcasting to the radio spectrum currently used for terrestrial AM radio broadcasts, including international shortwave transmissions. Over seventy broadcasters are now transmitting programs using the new standard, known as Digital Radio Mondiale (DRM), and / commercial DRM receivers are available (though there are few models on the DRM website and some are discontinued). DRM's system uses the MPEG-4 based standard aacPlus to code the music and CELP or HVXC for speech programs. At present these are priced too high to be affordable by many in the third world, however. Take-up of DRM has been minuscule and many traditional Shortwave broadcasters now only stream on Internet, use fixed satellite (TV set-boxes) or Local Analogue FM relays to save on costs. Very few (expensive) DRM radio sets are available and some Broadcasters (RTE in Ireland on 252 kHz) have ceased trials without launching a service.

Low-cost DAB radio receivers are now available from various Japanese manufacturers, and WorldSpace has worked with Thomson Broadcast to introduce a village communications center known as a Telekiosk to bring communications services to rural areas. The Telekiosks are self-contained and are available as fixed or mobile units

Two-way digital radio standards edit

The key breakthrough or key feature in digital radio transmission systems is that they allow lower transmission power, they can provide robustness to noise and cross-talk and other forms of interference, and thus allow the same radio frequency to be reused at shorter distance. Consequently, the spectral efficiency (the number of phonecalls per MHz and base station, or the number of bit/s per Hz and transmitter, etc.) may be sufficiently increased. Digital radio transmission can also carry any kind of information whatsoever — just as long at it has been expressed digitally. Earlier radio communication systems had to be made expressly for a given form of communications: telephone, telegraph, or television, for example. All kinds of digital communications can be multiplexed or encrypted at will.

See also edit

References edit

  1. ^ Britanak, Vladimir; Rao, K. R. (2017). Cosine-/Sine-Modulated Filter Banks: General Properties, Fast Algorithms and Integer Approximations. Springer. p. 478. ISBN 9783319610801. from the original on 2023-07-01. Retrieved 2019-10-24.
  2. ^ . Archived from the original on 2007-10-17.
  3. ^ "Digital Radio Mondiale - Technical Info". www.drm.org. from the original on 23 October 2017. Retrieved 29 April 2018.
  4. ^ "Digital Radio Mondiale - DRM+ Testing gets underway today in Stockholm, Sweden". www.drm.org. from the original on 2 February 2018. Retrieved 29 April 2018.
  5. ^ (PDF). Archived from the original (PDF) on 2008-03-08. Retrieved 2016-02-06.
  6. ^ Behrens, Steve. "Field testing resumes for radio’s digital best hope." Current, Aug. 16, 1999. Available at . Archived from the original on 2009-07-20. Retrieved 2009-06-15.
  7. ^ "iBiquity Digital Corporation - Automotive". from the original on 2008-11-17.
  8. ^ "FCC AUTHORIZES ALL-DIGITAL AM RADIO" (PDF). fcc.gov. Federal Communications Commission. October 27, 2020. (PDF) from the original on 2020-10-29. Retrieved 2020-10-27.
  9. ^ (CRTC), Government of Canada, Canadian Radio-television and Telecommunications Commission (15 December 2006). "Digital radio policy - In this public notice, the Commission sets out its revised policy for digital radio broadcasting". www.crtc.gc.ca. from the original on 2014-09-18.{{cite web}}: CS1 maint: multiple names: authors list (link)
  10. ^ "CRTC looking at bringing HD Radio to Canada". Fagstein. 16 January 2014. Archived from the original on 2014-04-29.
  11. ^ "Analogue radio will CONTINUE in Blighty as Minister of Fun dodges D-Day death sentence". The Register. from the original on 2016-11-10.
  12. ^ "Digital Radio Launch". Radioinfo. August 2009. from the original on 2019-05-28. Retrieved 2019-05-28.
  13. ^ Digital Radio Plus 2011-07-29 at the Wayback Machine (accessed 26 July 2011)

External links edit

  • "Digital, DTV, Internet, Mobile phone and MP3 Listening" - December 2006, RAJAR organisation.
  • - Search & and Listen to Live Radio Digitally

January 01, 1970
digital, radio, confused, with, internet, radio, digital, audio, broadcasting, redirects, here, specific, technical, standard, digital, audio, broadcasting, digital, technology, transmit, receive, across, radio, spectrum, digital, transmission, radio, waves, i. Not to be confused with Internet radio Digital audio broadcasting redirects here For the specific technical standard see Digital Audio Broadcasting Digital radio is the use of digital technology to transmit or receive across the radio spectrum Digital transmission by radio waves includes digital broadcasting and especially digital audio radio services Contents 1 Types 2 One way broadcasting systems 2 1 Broadcast standards 2 1 1 Digital audio broadcasting systems 2 1 2 Digital television DTV broadcasting systems 2 2 Status by country 2 2 1 DAB adopters 2 2 2 United States 2 2 3 Canada 2 2 4 United Kingdom 2 2 5 Germany 2 2 6 Norway 2 2 7 Other European Countries 2 2 8 Australia 2 2 9 Japan 2 2 10 Korea 2 2 11 Hong Kong 2 2 12 Developing nations 3 Two way digital radio standards 4 See also 5 References 6 External linksTypes editIn digital broadcasting systems the analog audio signal is digitized compressed using an audio coding format such as AAC MDCT 1 or MP2 and transmitted using a digital modulation scheme The aim is to increase the number of radio programs in a given spectrum to improve the audio quality to eliminate fading problems in mobile environments to allow additional datacasting services and to decrease the transmission power or the number of transmitters required to cover a region However analog radio AM and FM is still more popular and listening to radio over IP Internet Protocol is growing in popularity In 2012 four digital wireless radio systems are recognized by the International Telecommunication Union the two European systems Digital Audio Broadcasting DAB and Digital Radio Mondiale DRM the Japanese ISDB T and the in band on channel technique used in the US and Arab world and branded as HD Radio An older definition still used in communication engineering literature is wireless digital transmission technologies i e microwave and radio frequency communication standards where analog information signals as well as digital data are carried by a digital signal by means of a digital modulation method This definition includes broadcasting systems such as digital TV and digital radio broadcasting but also two way digital radio standards such as the second generation 2G cell phones and later short range communication such as digital cordless phones wireless computer networks digital micro wave radio links deep space communication systems such as communications to and from the two Voyager space probes etc A less common definition is radio receiver and transmitter implementations that are based on digital signal processing but may transmit or receive analog radio transmission standards for example FM radio This may reduce noise and distortion induced in the electronics It also allows software radio implementations where the transmission technology is changed just by selecting another piece of software In most cases this would however increase the energy consumption of the receiver equipment citation needed One way broadcasting systems editBroadcast standards edit Digital audio radio service standards may provide terrestrial or satellite radio service Digital radio broadcasting systems are typically designed for handheld mobile devices like mobile TV systems and unlike other digital TV systems which typically require a fixed directional antenna Some digital radio systems provide in band on channel IBOC solutions that may coexist with or simulcast with analog AM or FM transmissions while others are designed for designated radio frequency bands The latter allows one wideband radio signal to carry a multiplex of several radio channels of various bitrates as well as data services and other forms of media Some digital broadcasting systems allow single frequency network SFN where all terrestrial transmitters in a region sending the same multiplex of radio programs may use the same frequency channel without self interference problems further improving the system spectral efficiency While digital broadcasting offers many potential benefits its introduction has been hindered by a lack of global agreement on standards and many disadvantages The DAB Eureka 147 standard for digital radio is coordinated by the World DMB Forum This standard of digital radio technology was defined in the late 1980s and is now being introduced in some European countries Commercial DAB receivers began to be sold in 1999 and by 2006 500 million people were in the coverage area of DAB broadcasts although by this time sales had only taken off in the UK and Denmark In 2006 there are approximately 1 000 DAB stations in operation 2 There have been criticisms of the Eureka 147 standard and so a new DAB standard has been introduced The DRM standard has been used for several years to broadcast digitally on frequencies below 30 MHz shortwave mediumwave and longwave Also there is now the extended standard DRM which is designed for VHF bands 3 Tests of DRM has been made in countries such as in Brazil Germany France India Sri Lanka the UK Slovakia Italy incl the Vatican as well as Sweden 4 DRM is regarded by whom as a more transparent and less costly standard than DAB and thus a better choice for local radio citation needed commercial or community broadcasters Although DAB has been introduced in Australia the government concluded in 2011 that a preference for DRM and DRM above HD Radio could be used to supplement DAB services in some local and regional areas citation needed To date the following standards have been defined for one way digital radio Digital audio broadcasting systems edit Eureka 147 branded as DAB DAB ISDB TSB Internet radio Technically not a true Broadcast system T DMB V Radio FM band in band on channel FM IBOC HD Radio OFDM modulation over FM and AM band IBOC sidebands FMeXtra FM band IBOC subcarriers Digital Radio Mondiale extension DRM OFDM modulation over AM band IBOC sidebands Convergent Digital Radio CDR OFDM modulation over FM band IBOC sidebands AM band in band on channel AM IBOC HD Radio AM IBOC sideband Digital Radio Mondiale branded as DRM for the short medium and long wave bands Satellite radio WorldSpace in Asia and Africa Sirius XM Radio in North America MobaHo in Japan and the Republic of South Korea Systems also designed for digital TV DMB DVB H ISDB T DTMB Low bandwidth digital data broadcasting over existing FM radio Radio Data System branded as RDS Radio pagers FLEX ReFLEX POCSAG NTT Digital television DTV broadcasting systems edit Digital Video Broadcasting DVB Integrated Services Digital Broadcasting ISDB Digital Multimedia Broadcasting DMB Digital Terrestrial Television DTTV or DTT to fixed mainly roof top antennas DVB T based on OFDM modulation ISDB T based on OFDM modulation ATSC based on 8VSB modulation T DMB based on OFDM modulation Digital Terrestrial Multimedia Broadcast DTMB based on OFDM modulation Mobile TV reception in handheld devices DVB H based on OFDM modulation MediaFLO based on OFDM modulation DMB based on OFDM modulation Multimedia Broadcast Multicast Service MBMS via the GSM EDGE and UMTS cellular networks DVB SH based on OFDM modulation China Multimedia Mobile Broadcasting CMMB based on OFDM modulation Satellite TV DVB S for Satellite TV ISDB S 4DTV S DMB MobaHo Advanced Broadcasting System Satellite ABS S See also software radio for a discussion of radios which use digital signal processing Status by country edit DAB adopters edit Further information Countries using DAB DMB Digital Audio Broadcasting DAB also known as Eureka 147 has been adopted by around 20 countries worldwide It is based on the MPEG 1 Audio Layer II audio coding format and this has been co ordinated by the WorldDMB WorldDMB announced in November 2006 that DAB would be adopting the HE AACv2 audio coding format also known as eAAC Also being adopted are the MPEG Surround format and stronger error correction coding called Reed Solomon coding 5 The update has been named DAB Receivers that support the new DAB standard began being released during 2007 with firmware updated available for some older receivers DAB and DAB cannot be used for mobile TV because they do not include any video codecs DAB related standards Digital Multimedia Broadcasting DMB and DAB IP are suitable for mobile radio and TV both because they have MPEG 4 AVC and WMV9 respectively as video coding formats However a DMB video sub channel can easily be added to any DAB transmission as DMB was designed from the outset to be carried on a DAB subchannel DMB broadcasts in Korea carry conventional MPEG 1 Layer II DAB audio services alongside their DMB video services United States edit The United States has opted for the proprietary HD Radio technology a type of in band on channel IBOC technology According to iBiquity HD Radio is the company s trade name for its proprietary digital radio system but the name does not imply either high definition or hybrid digital as it is commonly incorrectly referenced Transmissions use orthogonal frequency division multiplexing a technique which is also used for European terrestrial digital TV broadcast DVB T HD Radio technology was developed and is licensed by iBiquity Digital Corporation It is widely believed by whom that a major reason for HD radio technology is to offer some limited digital radio services while preserving the relative stick values of the stations involved and to ensure that new programming services will be controlled by existing licensees The FM digital schemes in the U S provide audio at rates from 96 to 128 kilobits per second kbit s with auxiliary subcarrier transmissions at up to 64 kbit s The AM digital schemes have data rates of about 48 kbit s with auxiliary services provided at a much lower data rate Both the FM and AM schemes use lossy compression techniques to make the best use of the limited bandwidth Lucent Digital Radio USA Digital Radio USADR and Digital Radio Express commenced tests in 1999 of their various schemes for digital broadcast with the expectation that they would report their results to the National Radio Systems Committee NRSC in December 1999 6 Results of these tests remain unclear which in general describes the status of the terrestrial digital radio broadcasting effort in North America While traditional terrestrial radio broadcasters are trying to go digital most major US automobile manufacturers are promoting digital satellite radio HD Radio technology has also made inroads in the automotive sector with factory installed options announced by BMW Ford Hyundai Jaguar Lincoln Mercedes MINI and Volvo 7 Satellite radio is distinguished by its freedom from FCC censorship in the United States its relative lack of advertising and its ability to allow people on the road to listen to the same stations at any location in the country Listeners must currently pay an annual or monthly subscription fee in order to access the service Sirius Satellite Radio launched a constellation of three Sirius satellites during the course of 2000 The satellites were built by Space Systems Loral and were launched by Russian Proton boosters As with XM Satellite Radio Sirius implemented a series of terrestrial ground repeaters where satellite signal would otherwise be blocked by large structures including natural structures and high rise buildings XM Satellite Radio has a constellation of three satellites two of which were launched in the spring of 2001 with one following later in 2005 The satellites are Boeing 702 comsats and were put into orbit by Sea Launch boosters Back up ground transmitters repeaters will be built in cities where satellite signals could be blocked by big buildings On February 19 2007 Sirius Satellite Radio and XM Satellite Radio merged to form Sirius XM Radio The FCC has auctioned bandwidth allocations for satellite broadcast in the S band range around 2 3 GHz Terrestrial broadcasting has advantages in being free and local Satellite radio is neither of these things however in the early 21st century it has grown by providing uncensored content most notably the crossover of Howard Stern from terrestrial radio to satellite radio and commercial free all digital music channels that offer similar radio formats to local stations The HD Radio signal of an FM broadcast station in the US has a limited listening distance from the broadcast tower site FCC regulations currently limit the power of the digital part of the station s transmission to 10 of the existing analog power permitted the station Even at this power level the presence of the digital signal right next to the station s analog signal can result in older radios picking up noise due to trouble rejecting the adjacent digital signal There are still some concerns that HD Radio on FM will increase interference between different stations even though HD Radio at the 10 power level fits within the FCC spectral mask HD Radio HD Radio cite note 14 HD Radio allows each existing broadcast station to add additional channels in the US by transmitting a digital signal on both sides of its channel just beyond their existing analog Frequency Modulation signal The HD Radio signal occupies the 0 1 MHz that begins 0 1 MHz above and below the carrier frequency station For instance if a station s analog signal s carrier frequency is 93 3 MHz the digital signal will fill 93 1 93 2 MHz and 93 4 93 5 MHz within the FM Broadcast Band Several digital audio streams or subchannels can be carried within this single digital data stream with the number of audio of subchannels and bandwidth allocations at the choice of the station On the radio tuner these will appear as in the above case 93 3 2 93 3 3 and so on The frequencies that are used do not change as more channels are added to the one radio station 93 3 MHz in the example above Instead a fixed total amount of bandwidth is simply reallocated across the audio streams such that each now receives less bandwidth and therefore lower audio quality than before There is no federally mandated transition to HD Radio for both FM and AM Stations However on October 27 2020 the FCC approved voluntary all digital AM operation nationwide 8 Canada edit Canada has begun allowing experimental HD Radio broadcasts in December 2012 and digital audio subchannels on a case by case basis with the first stations in the country being CFRM FM in Little Current CING FM in Hamilton and CJSA FM in Toronto with a fourth CFMS FM in the Toronto suburb of Markham applying to operate HD Radio technology all within the province of Ontario 9 10 United Kingdom edit Main article Digital radio in the United Kingdom In the United Kingdom 44 3 of the population now has a DAB digital radio set and 34 4 of listening is to different digital platforms Because of the early success of the old DAB standard the transition to the more efficient DAB takes more time If DAB was switched off older receivers would become worthless In 2020 about half of the stations in the UK use DAB 26 million people or 39 6 of the population of 65 64 million now tune into digital radio each week up 2 6 million year on year according to RAJAR in Q1 2013 But FM listening has increased to 61 and DAB decreased to 21 DAB listeners may also use AM amp FM too 11 The UK currently has the world s biggest digital radio network with about 500 transmitters two nationwide DAB ensembles and 48 local and regional DAB ensembles broadcasting over 250 commercial and 34 BBC radio stations about 100 stations can be received in London On DAB digital radio most listeners can receive around 30 additional stations Digital radio stations are also distributed on digital television platforms such as Sky Virgin Media and Freeview as well as internet radio The Government will make a decision on a radio switchover subject to listening and coverage criteria being met A digital radio switchover would maintain FM as a platform while moving some services to DAB only distribution DAB devices in the UK has been available to the public by 2010 Germany edit In 2020 DAB signals cover more than 90 of Germany A national multiplex contains three public stations by Deutschlandfunk and 12 commercial stations In most areas additional multiplexes with public broadcasters and regional commercial stations are available The first DAB station network was deployed in Bavaria since 17 October 1995 until full coverage in 1999 Other states had funded a station network but the lack of success led them to scrap the funding the MDR switched off in 1998 already and Brandenburg declared a failure in 2004 Instead Berlin Brandenburg began to switch to digital radio based on an audio only DVB T mode given the success of the DVB T standard in the region when earlier analogue television was switched off in August 2003 being the first region to switch in Germany During that time the DVB H variant of the DVB family was released for transmission to mobile receivers in 2004 During 2005 most radio stations left the DAB network with only one public service broadcaster ensemble to remain in the now fully state funded station network At last the KEF de commission to determine the financial needs of broadcasters blocked federal funding on 15 July 2009 until economic viability of DAB broadcasting would be proven and pointing to DVB T as a viable alternative Digital radio deployment was rebooted during 2011 a joint commission of public and private radio broadcasters decided upon DAB as the new national standard in December 2010 The new station network started as planned on 1 August 2011 with 27 stations with 10 kW each giving a coverage of 70 across the nation A single Bundesmux fed mux short for federal multiplex was created on band 5C as a single frequency network on channel 5C see 1 With the initial market success of DAB the contractors decided on an expansion of the digital radio station network in November 2012 Norway edit Norway was the first country where analog FM radio was switched off in 2017 being replaced by nationwide DAB distribution Local stations can continue broadcasting in FM Other European Countries edit With DAB being available across Belgium Netherlands Switzerland Denmark Norway and Northern Italy there is good coverage across the European Backbone area see countries using DAB DMB indicating a sufficient momentum on the market France Spain Sweden and Poland use DAB only in the big cities Portugal and Finland abandoned DAB Finland is requesting the EU to mandate that automakers support FM similarly to DAB Australia edit Australia commenced regular digital audio broadcasting using the DAB standard on 4 May 2009 12 after many years of trialling alternative systems Normal radio services operate on the AM and FM bands as well as four stations ABC and SBS on digital TV channels The services are currently operating in the five state capital cities Adelaide Brisbane Melbourne Perth and Sydney and is being trialled in Canberra and Darwin 13 Japan edit Japan has started terrestrial sound broadcasting using ISDB Tsb and MobaHO 2 6 GHz Satellite Sound digital broadcasting Korea edit On 1 December 2005 South Korea launched its T DMB service which includes both television and radio stations T DMB is a derivative of DAB with specifications published by ETSI More than 110 000 receivers had been sold in one month only in 2005 Hong Kong edit Hong Kong replaced DAB with DVB T2 Lite Developing nations edit Digital radio is now being provided to the developing world A satellite communications company named WorldSpace was setting up a network of three satellites including AfriStar AsiaStar and AmeriStar to provide digital audio information services to Africa Asia and Latin America AfriStar and AsiaStar are in orbit AmeriStar cannot be launched from the United States as Worldspace transmits on the L band and would interfere with USA military as mentioned above citation needed in its heyday provided service to over 170 000 subscribers in eastern and southern Africa the Middle East and much of Asia with 96 coming from India Timbre Media along with Saregama India plan to relaunch the company As of 2013 Worldspace is defunct but two satellites are in orbit which still have a few channels See main WorldSpace article Each satellite provides three transmission beams that can support 50 channels each carrying news music entertainment and education and including a computer multimedia service Local regional and international broadcasters were working with WorldStar to provide services A consortium of broadcasters and equipment manufacturers are also working to bring the benefits of digital broadcasting to the radio spectrum currently used for terrestrial AM radio broadcasts including international shortwave transmissions Over seventy broadcasters are now transmitting programs using the new standard known as Digital Radio Mondiale DRM and commercial DRM receivers are available though there are few models on the DRM website and some are discontinued DRM s system uses the MPEG 4 based standard aacPlus to code the music and CELP or HVXC for speech programs At present these are priced too high to be affordable by many in the third world however Take up of DRM has been minuscule and many traditional Shortwave broadcasters now only stream on Internet use fixed satellite TV set boxes or Local Analogue FM relays to save on costs Very few expensive DRM radio sets are available and some Broadcasters RTE in Ireland on 252 kHz have ceased trials without launching a service Low cost DAB radio receivers are now available from various Japanese manufacturers and WorldSpace has worked with Thomson Broadcast to introduce a village communications center known as a Telekiosk to bring communications services to rural areas The Telekiosks are self contained and are available as fixed or mobile unitsTwo way digital radio standards editThe key breakthrough or key feature in digital radio transmission systems is that they allow lower transmission power they can provide robustness to noise and cross talk and other forms of interference and thus allow the same radio frequency to be reused at shorter distance Consequently the spectral efficiency the number of phonecalls per MHz and base station or the number of bit s per Hz and transmitter etc may be sufficiently increased Digital radio transmission can also carry any kind of information whatsoever just as long at it has been expressed digitally Earlier radio communication systems had to be made expressly for a given form of communications telephone telegraph or television for example All kinds of digital communications can be multiplexed or encrypted at will Digital cellular telephony 2G systems and later generations GSM UMTS sometimes called W CDMA TETRA IS 95 cdmaOne IS 136 D AMPS sometimes called TDMA IS 2000 CDMA2000 iDEN Digital Mobile Radio Project 25 a k a P25 or APCO 25 TETRA TETRAPOL NXDN dPMR DMR D STAR Wireless networking Wi Fi HIPERLAN Bluetooth DASH7 Zigbee 6LoWPAN Military radio systems for Network centric warfare JTRS Joint Tactical Radio System a flexible software defined radio SINCGARS Single channel ground to air radio system Amateur packet radio AX 25 Digital modems for HF PACTOR Satellite radio Satmodems Wireless local loop Basic Exchange Telephone Radio Service Broadband wireless access IEEE 802 16See also edit nbsp Radio portal Satellite televisionReferences edit Britanak Vladimir Rao K R 2017 Cosine Sine Modulated Filter Banks General Properties Fast Algorithms and Integer Approximations Springer p 478 ISBN 9783319610801 Archived from the original on 2023 07 01 Retrieved 2019 10 24 Digital Broadcast bringing the future to you Archived from the original on 2007 10 17 Digital Radio Mondiale Technical Info www drm org Archived from the original on 23 October 2017 Retrieved 29 April 2018 Digital Radio Mondiale DRM Testing gets underway today in Stockholm Sweden www drm org Archived from the original on 2 February 2018 Retrieved 29 April 2018 New High Efficiency Audio Option Added for DAB Digital Radio PDF Archived from the original PDF on 2008 03 08 Retrieved 2016 02 06 Behrens Steve Field testing resumes for radio s digital best hope Current Aug 16 1999 Available at Current org Testing digital radio systems 1999 Archived from the original on 2009 07 20 Retrieved 2009 06 15 iBiquity Digital Corporation Automotive Archived from the original on 2008 11 17 FCC AUTHORIZES ALL DIGITAL AM RADIO PDF fcc gov Federal Communications Commission October 27 2020 Archived PDF from the original on 2020 10 29 Retrieved 2020 10 27 CRTC Government of Canada Canadian Radio television and Telecommunications Commission 15 December 2006 Digital radio policy In this public notice the Commission sets out its revised policy for digital radio broadcasting www crtc gc ca Archived from the original on 2014 09 18 a href Template Cite web html title Template Cite web cite web a CS1 maint multiple names authors list link CRTC looking at bringing HD Radio to Canada Fagstein 16 January 2014 Archived from the original on 2014 04 29 Analogue radio will CONTINUE in Blighty as Minister of Fun dodges D Day death sentence The Register Archived from the original on 2016 11 10 Digital Radio Launch Radioinfo August 2009 Archived from the original on 2019 05 28 Retrieved 2019 05 28 Digital Radio Plus Archived 2011 07 29 at the Wayback Machine accessed 26 July 2011 External links edit Digital DTV Internet Mobile phone and MP3 Listening December 2006 RAJAR organisation Online Terrestrial Radio Search amp and Listen to Live Radio Digitally Retrieved from https en wikipedia org w index php title Digital radio amp oldid 1220740952, wikipedia, wiki, book, books, library,

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