DVB-T

Last updated

DVB-T, short for Digital Video Broadcasting — Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 [1] and first broadcast in Singapore in February, 1998. [2] [3] [4] [5] [6] [7] [8] This system transmits compressed digital audio, digital video and other data in an MPEG transport stream, using coded orthogonal frequency-division multiplexing (COFDM or OFDM) modulation. It is also the format widely used worldwide (including North America) for Electronic News Gathering for transmission of video and audio from a mobile newsgathering vehicle to a central receive point. It is also used in the US by Amateur television operators.

Contents

Basics

Rather than carrying one data carrier on a single radio frequency (RF) channel, COFDM works by splitting the digital data stream into a large number of slower digital streams, each of which digitally modulates a set of closely spaced adjacent sub-carrier frequencies. In the case of DVB-T, there are two choices for the number of carriers known as 2K-mode or 8K-mode. These are actually 1,705 or 6,817 sub-carriers that are approximately 4 kHz or 1 kHz apart.

DVB-T offers three different modulation schemes (QPSK, 16QAM, 64QAM).

DVB-T has been adopted or proposed for digital television broadcasting by many countries (see map), using mainly VHF 7 MHz and UHF 8 MHz channels whereas Taiwan, Colombia, Panama and Trinidad and Tobago use 6 MHz channels. Examples include the UK's Freeview.

The DVB-T Standard is published as EN 300 744, Framing structure, channel coding and modulation for digital terrestrial television. This is available from the ETSI website, as is ETSI TS 101 154, Specification for the use of Video and Audio Coding in Broadcasting Applications based on the MPEG-2 Transport Stream, which gives details of the DVB use of source coding methods for MPEG-2 and, more recently, H.264/MPEG-4 AVC as well as audio encoding systems. Many countries that have adopted DVB-T have published standards for their implementation. These include the D-book in the UK, the Italian DGTVi, [9] the ETSI E-Book and the Nordic countries and Ireland NorDig.

DVB-T has been further developed into newer standards such as DVB-H (Handheld), which was a commercial failure and is no longer in operation, and DVB-T2, which was initially finalised in August 2011.

DVB-T as a digital transmission delivers data in a series of discrete blocks at the symbol rate. DVB-T is a COFDM transmission technique which includes the use of a Guard Interval. It allows the receiver to cope with strong multipath situations. Within a geographical area, DVB-T also allows single-frequency network (SFN) operation, where two or more transmitters carrying the same data operate on the same frequency. In such cases the signals from each transmitter in the SFN needs to be accurately time-aligned, which is done by sync information in the stream and timing at each transmitter referenced to GPS.

The length of the Guard Interval can be chosen. It is a trade-off between data rate and SFN capability. The longer the guard interval the larger is the potential SFN area without creating intersymbol interference (ISI). It is possible to operate SFNs which do not fulfill the guard interval condition if the self-interference is properly planned and monitored.

Technical description of a DVB-T transmitter

Scheme of a DVB-T transmission system Dvbt tx scheme.svg
Scheme of a DVB-T transmission system

With reference to the figure, a short description of the signal processing blocks follows.

Spectrum of a DVB-T signal in 8k mode (note the flat-top characteristics) Dvbt spectrum.jpg
Spectrum of a DVB-T signal in 8k mode (note the flat-top characteristics)
Available bit rates (Mbit/s) for a DVB-T system in 8 MHz channels
ModulationCoding rate Guard interval
1/41/81/161/32
QPSK 1/24.9765.5295.8556.032
2/36.6357.3737.8068.043
3/47.4658.2948.7829.048
5/68.2949.2169.75810.053
7/88.7099.67610.24610.556
16-QAM 1/29.95311.05911.70912.064
2/313.27114.74515.61216.086
3/414.92916.58817.56418.096
5/616.58818.43119.51620.107
7/817.41819.35320.49121.112
64-QAM 1/214.92916.58817.56418.096
2/319.90622.11823.41924.128
3/422.39424.88226.34627.144
5/624.88227.64729.27330.160
7/826.12629.02930.73731.668

Technical description of the receiver

The receiving STB adopts techniques which are dual to those ones used in the transmission.

Countries and territories using DVB-T or DVB-T2

Digital terrestrial television systems worldwide. Countries using DVB-T or DVB-T2 are shown in blue. Digital broadcast standards.svg
Digital terrestrial television systems worldwide. Countries using DVB-T or DVB-T2 are shown in blue.

Americas

Europe

Oceania

Asia

Africa

DTT switch-off

While many countries have expected a shift to digital terrestrial television, a few have moved in the opposite direction following unsuccessful trials.

See also

Notes

  1. "ETSI EN 300 744 - Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for digital terrestrial television" (PDF). European Telecommunications Standards Institute. October 2015. p. 66.
  2. "DATAONE LIMITED RESPONSE TO CONSULTATION PAPER ON DATACASTING" (PDF). Infocomm Media Development Authority, Singapore.
  3. "TELEVISION BROADCAST FOR SINGAPORE - March 3, 1998" (PDF). 8 October 1999. Archived (PDF) from the original on 8 October 1999. Retrieved 5 February 2020.
  4. "Advent Television launches the world's first digital terrestrial service in Singapore" (PDF). 8 October 1999. Archived (PDF) from the original on 8 October 1999. Retrieved 5 February 2020.
  5. "The Future is in Digital Broadcasting and that future is with Advent Television". 11 April 2001. Archived from the original on 11 April 2001. Retrieved 5 February 2020.
  6. "Press Release - April 27, 1998" (PDF). 4 June 2000. Archived (PDF) from the original on 4 June 2000. Retrieved 5 February 2020.
  7. "S'pore testing digital TV format". The Business Times. 5 March 1998. p. 4.
  8. "SBA plans to launch digital TV after trying out systems". The Straits Times. 9 March 1998. p. 30.
  9. "DGTVi - Per la Televisione Digitale Terrestre" (in Italian). Archived from the original on 2008-04-19. Retrieved 2008-07-30.CS1 maint: unfit URL (link)
  10. DVB.org Archived 2011-03-20 at the Wayback Machine , Official information taken from the DVB website
  11. "About - DVB". Archived from the original on 1 September 2013. Retrieved 26 June 2016.
  12. "Colombia adopta el estándar europeo para la tv digital terrestre". El Espectador (in Spanish). 28 August 2008. Archived from the original on 13 April 2019. Retrieved 28 August 2008.
  13. "TV Digital no ha llegado a toda Colombia y la CNTV ya piensa en modificar la norma". Evaluamos (in Spanish). 21 July 2011.
  14. "Panama adopts DVB-T". DVB.org. 19 May 2009. Archived from the original on 3 September 2013. Retrieved 26 June 2016.
  15. "KTV Ltd" . Retrieved 26 June 2016.
  16. "Plan for the introduction of terrestrial digital television broadcasting (DVB-T) in the Republic of Bulgaria" (in Bulgarian). Ministry of Transport, Information Technology and Communications of Bulgaria . Retrieved 17 December 2012.
  17. "Digital Television". NURTS (TV tower operator). Archived from the original on 1 December 2012. Retrieved 17 December 2012.
  18. "Digital Ísland" (in Icelandic). fjarskiptahandbokin.is. Archived from the original on 31 August 2009. Retrieved 27 October 2009.
  19. "Russia adopts DVB-T2". Advanced-Television.com. 29 September 2011.
  20. "ETV: trial DVB-T2 network" (in Serbian). Archived from the original on 16 April 2012. Retrieved 22 March 2012.
  21. https://www.broadbandtvnews.com/2018/12/06/switzerland-to-switch-off-dtt-on-june-3-2019/
  22. "100,000 likes – Oqaab reaches over 1 Mio TV Households". Oqaab.af. 31 March 2015. Archived from the original on 23 March 2016. Retrieved 26 June 2016.
  23. 1 2 3 4 5 6 7 8 Hawkes, Rebecca (19 May 2014). "Samart eyes Middle East market for digital TV-enabled smartphone". Rapid TV News. Retrieved 26 June 2016.
  24. "Digital TV services to be introduced in Bangladesh by 2014". Asia-Pacific Broadcasting Union. 5 June 2012.
  25. "PERSYARATAN TEKNIS ALAT DAN PERANGKAT PENERIMA TELEVISI SIARAN DIGITAL BERBASIS STANDAR DIGITAL VIDEO BROADCASTING TERRESTRIAL – SECOND GENERATION" (PDF). KomInfo.go.id. Ministry of Communication and Information Technology (Indonesia) . Retrieved 1 April 2017.
  26. "Standar Penyiaran Televisi Digital" (PDF). KomInfo.go.id. Ministry of Communication and Information Technology (Indonesia). Archived from the original (PDF) on 27 June 2017. Retrieved 19 February 2012.
  27. Hawkes, Rebecca (26 February 2014). "Kuwait TV opts for Harris DVB-T2 technology". Rapid TV News. Retrieved 11 April 2014.
  28. "Kyrgyztelecom launches DVB-T2 & DVB-S2". DVB.org. 7 November 2014. Archived from the original on 19 April 2016. Retrieved 7 April 2016.
  29. "北朝鮮で4局が地上デジタル放送を実施中、ASUS ZenFone Go TVで確認". blogofmobile.com (in Japanese). 8 September 2019. Retrieved 24 June 2020.
  30. Williams, Martyn (17 March 2013). "Report: DPRK testing digital TV". North Korea Tech - 노스코리아테크. Archived from the original on 23 September 2019. Retrieved 25 September 2019.
  31. "Qatar Goes DVB-T2". DVB.org. 11 December 2013. Archived from the original on 26 September 2019. Retrieved 12 April 2014.
  32. "Tajikistan Confirms DVB-T2 Adoption". DVB.org. 4 February 2014. Archived from the original on 29 December 2016. Retrieved 7 April 2016.
  33. Mochiko, Thabiso (26 November 2010). "BusinessDay - State U-turn on Nyanda's digital-TV signal plan". BusinessDay.co.za. BDFM Publishers. Archived from the original on 30 November 2010. Retrieved 26 November 2010.
  34. Etherington-Smith, James (3 January 2011). "DVB-T2 chosen as digital TV standard". MyBroadband.co.za. Retrieved 3 January 2011.

Related Research Articles

Digital television television transmission using digital encoding

Digital television (DTV) is the transmission of television audiovisual signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high definition (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio in contrast to the narrower format of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards:

In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission and a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL internet access, wireless networks, power line networks, and 4G/5G mobile communications.

Digital Video Broadcasting open standard for digital television broadcasting

Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) of the European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC) and European Broadcasting Union (EBU).

Digital Video Broadcasting - Cable (DVB-C) is the DVB European consortium standard for the broadcast transmission of digital television over cable. This system transmits an MPEG-2 or MPEG-4 family digital audio/digital video stream, using a QAM modulation with channel coding. The standard was first published by the ETSI in 1994, and subsequently became the most widely used transmission system for digital cable television in Europe, Asia and South America. It is deployed worldwide in systems ranging from the larger cable television networks (CATV) down to smaller satellite master antenna TV (SMATV) systems.

The Integrated Services Digital Broadcasting is a Japanese standard for digital television (DTV) and digital radio used by the country's radio and television networks. ISDB supersedes both the NTSC-J analog television system and the previously used MUSE Hi-vision analog HDTV system in Japan as well as the NTSC, PAL-M, and PAL-N broadcast standards in South America and the Philippines. Digital Terrestrial Television Broadcasting (DTTB) services using ISDB-T started in Japan in December 2003 and Brazil in December 2007 as a trial. Since then, many countries have adopted ISDB over other digital broadcasting standards.

Advanced Television Systems Committee (ATSC) standards are an American set of standards for digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard and, like that standard, is used mostly in the United States, Mexico, Canada, and South Korea. Several former NTSC users, in particular Japan, have not used ATSC during their digital television transition, because they adopted their own system called ISDB.

Digital Radio Mondiale Digital radio broadcasting standard

Digital Radio Mondiale is a set of digital audio broadcasting technologies designed to work over the bands currently used for analogue radio broadcasting including AM broadcasting, particularly shortwave, and FM broadcasting. DRM is more spectrally efficient than AM and FM, allowing more stations, at higher quality, into a given amount of bandwidth, using xHE-AAC audio coding format. Various other MPEG-4 and Opus codecs are also compatible, but the standard now specifies xHE-AAC.

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.

Broadcast television systems are the encoding or formatting standards for the transmission and reception of terrestrial television signals. There were three main analog television systems in use around the world until the late 2010s: NTSC, PAL, and SECAM. Now in digital terrestrial television (DTT), there are four main systems in use around the world: ATSC, DVB, ISDB and DTMB.

Digital terrestrial television is a technology for terrestrial television in which land-based (terrestrial) television stations broadcast television content by radio waves to televisions in consumers' residences in a digital format. DTTV is a major technological advance over the previous analog television, and has largely replaced analog which had been in common use since the middle of the 20th century. Test broadcasts began in 1998 with the changeover to DTTV beginning in 2006 and is now complete in many countries. The advantages of digital terrestrial television are similar to those obtained by digitising platforms such as cable TV, satellite, and telecommunications: more efficient use of limited radio spectrum bandwidth, provision of more television channels than analog, better quality images, and potentially lower operating costs for broadcasters.

Single-frequency network

A single-frequency network or SFN is a broadcast network where several transmitters simultaneously send the same signal over the same frequency channel.

Digital terrestrial television in the United Kingdom encompasses over 100 television, radio and interactive services broadcast via the United Kingdom's terrestrial television network and receivable with a standard television set. The majority of digital terrestrial television (DTT) services, including the five former analogue channels, are broadcast free-to-air, and a further selection of encrypted pay TV services are also available.

ISDB-T International, or SBTVD, short for Sistema Brasileiro de Televisão Digital, is a technical standard for digital television broadcast used in Brazil, Argentina, Peru, Botswana, Chile, Honduras, Venezuela, Ecuador, Costa Rica, Paraguay, Philippines, Bolivia, Nicaragua, El Salvador and Uruguay, based on the Japanese ISDB-T standard. ISDB-T International launched into commercial operation on December 2, 2007, in São Paulo, Brazil, as SBTVD.

Freeview (New Zealand)

Freeview is New Zealand's free-to-air television platform. It is operated by a joint venture between the country's major free-to-air broadcasters – government-owned Television New Zealand and Radio New Zealand, government-subsidised Māori Television, and the American-owned Discovery New Zealand. It consists of a HD-capable digital terrestrial television service, to around 86% of the population in the major urban and provincial centres of New Zealand, and a standard-definition satellite television service, called Freeview Satellite, covering the whole of mainland New Zealand and the major offshore islands. Freeview uses the DVB-S and DVB-T standards on government-provided spectrum.

DTMB is the digital TV standard for mobile and fixed devices, developed in the People's Republic of China. It is used there and in both of their special administrative regions, and also in Cambodia, the Comoros, Cuba, East Timor, Laos and Pakistan. In Pakistan, as part of the China–Pakistan Economic Corridor Project, ZTE Corporation will provide Pakistan Television Corporation collaboration across several digital terrestrial television technologies, staff training and content creation including partnerships with Chinese multinational companies in multiple areas including television sets and set top boxes as a form of "International Cooperation".

Digital television adapter Type of television tuner to display digital signals on analog sets

A digital television adapter (DTA), commonly known as a converter box or decoder box, is a television tuner that receives a digital television (DTV) transmission, and converts the digital signal into an analog signal that can be received and displayed on an analog television set. Some also have an HDMI output since some TVs with HDMI do not have a digital tuner. The input digital signal may be over-the-air terrestrial television signals received by a television antenna, or signals from a digital cable system. It normally does not refer to satellite TV, which has always required a set-top box either to operate the big satellite dish, or to be the integrated receiver/decoder (IRD) in the case of direct-broadcast satellites (DBS).

DVB-T2 is an abbreviation for "Digital Video Broadcasting — Second Generation Terrestrial"; it is the extension of the television standard DVB-T, issued by the consortium DVB, devised for the broadcast transmission of digital terrestrial television. DVB has been standardized by ETSI.

Digital multimedia broadcasting The South Korean digital TV standard

Digital multimedia broadcasting (DMB) is a digital radio transmission technology developed in South Korea as part of the national IT project for sending multimedia such as TV, radio and datacasting to mobile devices such as mobile phones, laptops and GPS navigation systems. This technology, sometimes known as mobile TV, should not be confused with Digital Audio Broadcasting (DAB) which was developed as a research project for the European Union.

References