Digital television

A map depicting digital terrestrial television standards

Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. In the 2000s[1] it was represented as the first significant evolution in television technology since color television in the 1950s.[2] Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio (commonly 16:9) in contrast to the narrower format (4:3) 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,[3] 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:

History

Background

Digital television's roots in the 1990s are tied to the availability of inexpensive, high-performance computers that can compress video.[8] Digital television was previously impractical due to high bandwidth requirements of uncompressed video,[9][10] requiring around 200 Mbit/s for a standard-definition television (SDTV) signal,[9] and over 1 Gbit/s for high-definition television (HDTV).[10]

Development

In the mid-1980s, Toshiba commercially released one of the first television sets with digital capabilities, using integrated circuit chips such as a microprocessor to convert analog television broadcast signals to digital video signals, enabling features such as freezing pictures and showing two channels at once. Following in 1986, Sony and NEC Home Electronics announced their own similar TV sets with digital video capabilities. However, these television sets still relied on analog TV broadcast signals, with true digital TV broadcasts not yet being available at the time.[11][12]

A digital TV broadcast service was proposed in 1986 by Nippon Telegraph and Telephone (NTT) and the Ministry of Posts and Telecommunication (MPT) in Japan, where there were plans to develop an "Integrated Network System" service. However, practical digital TV service implementation was not available until the adoption of motion-compensated DCT video compression formats such as MPEG made it possible in the early 1990s.[9]

In the mid-1980s, as Japanese consumer electronics firms forged ahead with the development of HDTV technology, and the MUSE analog format was proposed by Japan's public broadcaster NHK as a worldwide standard. Until June 1990, the Japanese MUSE standard—based on an analog system—was the front-runner, set to eclipse US electronics company solutions, among the more than 23 different technical concepts under consideration.

Simultaneously, between 1988 and 1991, European organizations: CMMT, ETSI, etc. were working on DCT-based digital video coding standards for both SDTV and HDTV. The EU 256 project by the CMTT and ETSI, along with research by Italian broadcaster RAI, developed a DCT video codec that broadcast SDTV at 34 Mbit/s and near-studio-quality HDTV at about 70–140 Mbit/s. RAI demonstrated this with a 1990 FIFA World Cup broadcast in March 1990.[10][13]

In the late 1980s, both Japan (NHK) and Europe (the EU and various companies such as Philips and Thomson) were developing analog HDTV systems, called MUSE and HD-MAC respectively. Then, General Instrument Corporation's VideoCipher Division, based in San Diego, California, announced the development of an all-digital HDTV system. [14]. [15] General Instrument demonstrated the feasibility of a digital HDTV signal, persuading the FCC to delay its decision on an advanced television (ATV) standard until a digitally based standard could be developed, resulting in several actions. First, the FCC declared that the new TV standard must be more than an enhanced analog signal, capable of providing a genuine HDTV signal with at least twice the resolution of existing television images. Second, to ensure that viewers who did not wish to buy a new digital television set could continue to receive conventional television broadcasts, it dictated that the new ATV standard must be capable of being simulcast with NTSC on different channels. The new ATV standard also allowed the new DTV signal to be based on entirely new design principles, incorporating many improvements over existing analog television.[8]

General Instrument (GI), however, recognized that digital HDTV would likely take many years for product and market development, and decided to base its original product development and marketing plans on a digital standard definition system (digital SDTV) for satellite TV and cable TV applications, receivable by the large installed base of NTSC and PAL television sets around the world. At the September 1990 International Broadcasting Convention (IBC) trade show in Brighton England, GI demonstrated its DigiCipher digital television system, with a flexible degree of compression from 2:1 (HD) up to 10:1 (SD) within a satellite transponder or 6 MHz cable TV channel.[16]

The HDTV process, meanwhile, was going through a rigorous process conducted by the FCC's Advisory Committee on Advanced Television Service (ACATS) through its Advanced Television Test Center (ATTC) located in Alexandria, Virginia. Six HDTV systems were tested sequentially in 1992, with the lead digital HDTV systems being developed by General Instrument, in partnership with MIT; by a competing consortium of Philips, Thomson, Sarnoff Labs, and NBC; and by another alliance of Zenith Electronics and AT&T. After the testing phase, the various companies were encouraged to come together in a "Grand Alliance," with a goal of combining the various technologies into a unified system.[17] Key technical elements of the system included MPEG-2 video (with interlaced and progressive formats), Dolby AC-3 audio, MPEG-2 transport, System Information tables, and 8-VSB transmission.[18]

A universal standard for scanning formats, aspect ratios, or lines of resolution was not produced by the FCC's final standard. This outcome resulted from a dispute between the consumer electronics industry (joined by some broadcasters) and the computer industry (joined by the film industry and some public interest groups) over which of the two scanning processes—interlaced or progressive—is superior. Interlaced scanning, which is used by the electronics industry in televisions worldwide, scans even-numbered lines first, then odd-numbered ones. Progressive scanning, which is the format used in computers, scans lines in sequences, from top to bottom. The computer industry argued that progressive scanning is superior because it does not flicker in the manner of interlaced scanning. It also argued that progressive scanning enables easier connections with the Internet and is more cheaply converted to interlaced formats than vice versa. The film industry also supported progressive scanning because it offers a more efficient means of converting filmed programming into digital formats. The consumer electronics industry and broadcasters argued that interlaced scanning was the only technology that could transmit the highest quality pictures then (and currently) feasible, i.e., 1,080 lines per picture and 1,920 pixels per line. Broadcasters also favored interlaced scanning because their vast archive of interlaced programming is not readily compatible with a progressive format.[8]


Inaugural launches

In June 1992, General Instrument and HBO commenced a field trial of GI's DigiCipher SDTV system for delivery from HBO's Hauppauge, NY satellite uplink site to various cable headends in the U.S. While the field trial was successful from a technical and marketing perspective, HBO wanted to delay its digital TV launch until major cable operators such as TCI decided how to proceed with digital TV. Meanwhile, various international television programmers decided to take advantage of GI's DigiCipher system immediately, including Rogers Cablesystems in Canada, Multivision in Mexico City, and Telefe in Argentina. TCI and other cable operators decided they would wait for GI's MPEG-2 based system (DigiCipher II) for delivery of digital SDTV over cable, beginning in 1996. In the intervening period, many US programmers, including HBO, Showtime, ESPN, and PBS, and pay-per-view programmers Viewers Choice and Request Television, launched digital SDTV signals over satellite to cable TV headends, with GI agreeing to upgrade their technology to the MPEG-2 compatible DigiCipher II system when it became available. [19]

As for digital SDTV signals reaching all the way to consumers' homes, PrimeStar in the US became the world's first digital TV service, launching with GI's DigiCipher system on March 22, 1994.[20] DirecTV in the US launched next, with its digital satellite platform in the summer of 1994[21], using the Digital Satellite System (DSS) standard.[22][23] In 1995, another high-power Direct Broadcast Satellite (DBS) system, Dish Networks, was launched by Echostar.

The launch of digital cable in the U.S., along with the upgrading of GI's growing DigiCipher content provider customer base, hinged upon the successful resolution of the intellectual property related to the MPEG-2 video standard. The Grand Alliance HDTV standard also depended on resolution of this matter. Since there were numerous patents essential to the MPEG-2 standard owned by multiple parties, it became a significant area of concern. Led by CableLabs, the US cable industry's R&D consortium, a group of the leading MPEG-2 patent holders at the time was put together, chaired by Marc Tayer, GI's Director of Licensing and Business Development. In addition to GI, other members of this international MPEG-2 Intellectual Property Rights (IPR) group consisted of Sony, Matsushita, Philips, and Thomson Consumer Electronics. After a series of meetings and negotiations, the group finally agreed on a suitable joint licensing structure.[24] This milestone activity culminated in July 1997 at a press conference in Tokyo. Since many companies were already shipping MPEG-2 compatible digital satellite and cable TV products, it was a major relief to see the licensing issue resolved.[25]

Digital cable broadcasts had been tested and launched in the US starting in 1996 by TCI and Comcast, followed by many other cable operators throughout the US.[26][27] The first digital terrestrial platform was launched in November 1998 as ONdigital in the UK, using the DVB-T standard.[28]

As the turn of the century approached, the "chicken and egg" HDTV situation between content availability (lack thereof) and the small installed base of consumer HDTV sets began to make progress. The FCC had mandated that US TV stations in the top 30 markets, covering half of US television households, must start broadcasting digital signals by November 1999. There was no requirement, however, for the content to be in HDTV format, so long as it was in a digital SDTV format. CBS began some limited digital HD broadcasting of certain special events, such as the October 1998 spectacle of astronaut and US Senator John Glenn becoming the oldest person to fly in space aboard the space shuttle Discovery, with 8 CBS affiliates carrying the network broadcast in high definition. The following month, ABC delivered the movie 101 Dalmations in HD, and then on January 30, 2000 ABC broadcast Super Bowl XXXIV in HD. In the satellite and cable world, HBO launched HBO HD in March 1999, using GI's MPEG-2 compatible DigiCipher HDTV system, followed by Viacom's Showtime HD launch in 2000. By March 2003, ESPN deployed Motorola's DigiCipher HDTV system (in 2000, GI had been acquired by Motorola) to debut its new ESPN HD channel with the Major League Baseball season opener, and a plan to deliver 100 professional baseball, basketball, hockey, and football games live in HD. Then, in July of 2003, Cablevision Systems, through its Rainbow content subsidiary, launched Voom, a high-power DBS satellite and service dedicated to HDTV. By 2004 Voom was delivering 36 HDTV satellite channels including 21 unique channels programmed by Rainbow Media. The Voom satellite was sold, however, to Dish Networks, ending the Voom standalone service. Regardless, it appeared that digital HDTV was finally well positioned for the future of home television entertainment.[29]

Technical information

Formats and bandwidth

Comparison of image quality between ISDB-T (1080i broadcast, top) and NTSC (480i transmission, bottom)

Digital television supports many different picture formats defined by the broadcast television systems which are a combination of size and aspect ratio (width to height ratio).

With digital terrestrial television (DTT) broadcasting, the range of formats can be broadly divided into two categories: high-definition television (HDTV) for the transmission of high-definition video and standard-definition television (SDTV). These terms by themselves are not very precise and many subtle intermediate cases exist.

One of several different HDTV formats that can be transmitted over DTV is: 1280 × 720 pixels in progressive scan mode (abbreviated 720p) or 1920 × 1080 pixels in interlaced video mode (1080i). Each of these uses a 16:9 aspect ratio. Uncompressed HDTV cannot be transmitted over analog television channels because of channel capacity issues.

SDTV, by comparison, may use one of several different formats taking the form of various aspect ratios depending on the technology used in the country of broadcast. NTSC can deliver a 640 × 480 resolution in 4:3 and 854 × 480 in 16:9, while PAL can give 768 × 576 in 4:3 and 1024 × 576 in 16:9. However, broadcasters may choose to reduce these resolutions to reduce bit rate (e.g., many DVB-T channels in the UK use a horizontal resolution of 544 or 704 pixels per line).[30]

Each commercial broadcasting terrestrial television DTV channel in North America is allocated enough bandwidth to broadcast up to 19 megabits per second using 8VSB modulation.[31] However, the broadcaster does not need to use this entire bandwidth for just one broadcast channel. Instead, the broadcast can use Program and System Information Protocol and subdivide across several video subchannels (a.k.a. feeds) of varying quality and compression rates, including non-video datacasting services.

A broadcaster may opt to use a standard-definition (SDTV) digital signal instead of an HDTV signal, because current convention allows the bandwidth of a DTV channel (or "multiplex") to be subdivided into multiple digital subchannels, (similar to what most FM radio stations offer with HD Radio), providing multiple feeds of entirely different television programming on the same channel. This ability to provide either a single HDTV feed or multiple lower-resolution feeds is often referred to as distributing one's bit budget or multicasting. This can sometimes be arranged automatically, using a statistical multiplexer. With some implementations, image resolution may be less directly limited by bandwidth; for example in DVB-T, broadcasters can choose from several different modulation schemes, giving them the option to reduce the transmission bit rate and possibly improve reception for more distant or mobile viewers.

Reception

There are several different ways to receive digital television. One of the oldest means of receiving DTV (and TV in general) is from terrestrial transmitters using an antenna (known as an aerial in some countries). This delivery method is known as digital terrestrial television (DTT). With DTT, viewers are limited to channels that have a terrestrial transmitter within range of their antenna.

Other delivery methods include digital cable and digital satellite. In some countries where transmissions of TV signals are normally achieved by microwaves, digital multichannel multipoint distribution service is used. Other standards, such as digital multimedia broadcasting (DMB) and digital video broadcasting - handheld (DVB-H), have been devised to allow handheld devices such as mobile phones to receive TV signals. Another way is Internet Protocol television (IPTV), which is the delivery of TV over a computer network. Finally, an alternative way is to receive digital TV signals via the open Internet (Internet television), whether from a central streaming service or a P2P (peer-to-peer) system.

Some television signals are protected by encryption and backed up with the force of law under the WIPO Copyright Treaty and national legislation implementing it, such as the US Digital Millennium Copyright Act.[32] Access to encrypted channels can be controlled by a removable card, for example via the Common Interface or CableCard.

Protection parameters

Digital television signals should not interfere with each other and many times coexist with analog television until it is phased out. The following table gives allowable signal-to-noise and signal-to-interference ratios for various interference scenarios. This table is a crucial regulatory tool for controlling the placement and power levels of digital television stations. Digital TV is more tolerant of interference than analog TV.[33]

System Parameters
(protection ratios) 		Canada US EBU
ITU-mode M3 		Japan & Brazil[A]
C/N for AWGN Channel +19.5 dB
(16.5 dB[B]) 		+15.19 dB +19.3 dB +19.2 dB
Co-Channel DTV into Analog TV +33.8 dB +34.44 dB +34 ≈37 dB +38 dB
Co-Channel Analog TV into DTV +7.2 dB +1.81 dB +4 dB +4 dB
Co-Channel DTV into DTV +19.5 dB
(16.5 dB[B]) 		+15.27 dB +19 dB +19 dB
Lower Adjacent Channel DTV into Analog TV −16 dB −17.43 dB −5 ~ −11 dB[C] −6 dB
Upper Adjacent Channel DTV into Analog TV −12 dB −11.95 dB −1 ~ −10[C] −5 dB
Lower Adjacent Channel Analog TV into DTV −48 dB −47.33 dB −34 ~ −37 dB[C] −35 dB
Upper Adjacent Channel Analog TV into DTV −49 dB −48.71 dB −38 ~ −36 dB[C] −37 dB
Lower Adjacent Channel DTV into DTV −27 dB −28 dB −30 dB −28 dB
Upper Adjacent Channel DTV into DTV −27 dB −26 dB −30 dB −29 dB
  1. ^ ISDB-T (6 MHz, 64QAM, R=2/3), Analog TV (M/NTSC).
  2. ^ a b The Canadian parameter, C/(N+I) of noise plus co-channel DTV interface should be 16.5 dB.
  3. ^ a b c d Depending on analog TV systems used.

Interaction

Viewers can interact and provide data back to broadcasters with DTV systems in various ways shown in the list below. Return path to the broadcaster is possible in post 2020s DTV systems typically via the viewers internet connection. Some DTV systems support video on demand using a communication channel localized to a neighborhood rather than a city (terrestrial) or an even larger area (satellite)

  1. Browse the electronic program guide.
  2. Targeted advertising[34]
  3. Viewing statistics[35]

Comparison to analog

DTV has several advantages over analog television,

  • More efficient bandwidth usage provide more digital channels in the same space and/or provide high-definition television service
  • Digital TV signals require less transmission power than analog TV signals to be broadcast and received satisfactorily.[36]
  • Flexible bandwidth allocations are flexible depending on the level of compression and resolution of the transmitted image.
  • More sound channels. Analog TV began with monophonic sound and later developed multichannel television sound with two independent audio signal channels. DTV allows up to 5 audio signal channels plus a subwoofer bass channel, producing broadcasts similar in quality to movie theaters and DVDs.[37]
  • Can provide for sale of non-television services such as multimedia on demand or interactive purchasing.
  • Permits special services such as multiplexing (more than one program on the same channel), electronic program guides and additional languages (spoken or subtitled).

Digital and analog signals react to interference differently. For example, common problems with analog television include ghosting of images, noise from weak signals and other problems that degrade the quality of the image and sound, although the program material may still be watchable. With digital television, because of the cliff effect, reception of the digital signal must be very nearly complete; otherwise, neither audio nor video will be usable.

Compression artifacts, picture quality monitoring and allocated bandwidth

DTV images have some picture defects not present on analog television or motion picture cinema, because of present-day limitations of bit rate and compression algorithms such as MPEG-2. This defect is sometimes referred to as mosquito noise.[38]

Because of the way the human visual system works, defects in an image that are localized to particular features of the image or that come and go are more perceptible than defects that are uniform and constant. However, the DTV system is designed to take advantage of other limitations of the human visual system to help mask these flaws, e.g., by allowing more compression artifacts during fast motion where the eye cannot track and resolve them as easily and, conversely, minimizing artifacts in still backgrounds that, because time allows, may be closely examined in a scene.

Broadcast, cable, satellite and Internet DTV operators control the picture quality of television signal encoders using sophisticated, neuroscience-based algorithms, such as the structural similarity index measure (SSIM) video quality measurement tool. Another tool called visual information fidelity (VIF), is used in the Netflix VMAF video quality monitoring system.

Quantising effects can create contours—rather than smooth gradations—on areas with small graduations in amplitude. Typically, a very flat scene, such as a cloudless sky, will exhibit visible steps across its expanse, often appearing as concentric circles or ellipses. This is known as color banding. Similar effects can be seen in very dark scenes, where true black backgrounds are overlaid by dark gray areas. These transitions may be smooth, or may show a scattering effect as the digital processing dithers and is unable to consistently allocate a value of either absolute black or the next step up the greyscale.

Effects of poor reception

Changes in signal reception from factors such as degrading antenna connections or changing weather conditions may gradually reduce the quality of analog TV. The nature of digital TV results in a perfectly decodable video initially, until the receiving equipment starts picking up interference that overpowers the desired signal or if the signal is too weak to decode. Some equipment will show a garbled picture with significant damage, while other devices may go directly from perfectly decodable video to no video at all or lock up.[39] This phenomenon is known as the digital cliff effect.[40]

Block errors may occur when transmission is done with compressed images. A block error in a single frame often results in black boxes in several subsequent frames, making viewing difficult.

For remote locations, distant channels that, as analog signals, were previously usable in a snowy and degraded state may, as digital signals, be perfectly decodable or may become completely unavailable. The use of higher frequencies add to these problems, especially in cases where a clear line-of-sight from the receiving antenna to the transmitter is not available because usually higher frequency signals can't pass through obstacles as easily.

Effect on old analog technology

Television sets with only analog tuners cannot decode digital transmissions. When analog broadcasting over the air ceases, users of sets with analog-only tuners may use other sources of programming (e.g., cable, recorded media) or may purchase set-top converter boxes to tune in the digital signals. In the United States, a government-sponsored coupon was available to offset the cost of an external converter box.

The digital television transition began around the late 1990s and has been completed on a country-by-country basis in most parts of the world.

Disappearance of TV-audio receivers

Prior to the conversion to digital TV, analog television broadcast audio for TV channels on a separate FM carrier signal from the video signal. This FM audio signal could be heard using standard radios equipped with the appropriate tuning circuits.

However, after the digital television transition, no portable radio manufacturer has yet developed an alternative method for portable radios to play just the audio signal of digital TV channels; DTV radio is not the same thing.

Environmental issues

The adoption of a broadcast standard incompatible with existing analog receivers has created the problem of large numbers of analog receivers being discarded. One superintendent of public works was quoted in 2009 saying; "some of the studies I’ve read in the trade magazines say up to a quarter of American households could be throwing a TV out in the next two years following the regulation change."[41] In Michigan in 2009, one recycler estimated that as many as one household in four would dispose of or recycle a TV set in the following year.[42] The digital television transition, migration to high-definition television receivers and the replacement of CRTs with flat screens are all factors in the increasing number of discarded analog CRT-based television receivers. In 2009, an estimated 99 million analog TV receivers were sitting unused in homes in the US alone and, while some obsolete receivers are being retrofitted with converters, many more are simply dumped in landfills where they represent a source of toxic metals such as lead as well as lesser amounts of materials such as barium, cadmium and chromium.[43][44]

See also

References

  1. ^ "The Origins and Future Prospects of Digital Television". Benton Foundation. 2008-12-22. Retrieved 2025-07-06.
  2. ^ Kruger, Lennard G. (2002). Digital Television: An Overview. New York: Nova Publishers. ISBN 1-59033-502-3.
  3. ^ "HDTV Set Top Boxes and Digital TV Broadcast Information". Archived from the original on 22 May 2016. Retrieved 28 June 2014.
  4. ^ Ong, C. Y., Song, J., Pan, C., & Li, Y.(2010, May). Technology and Standards of Digital Television Terrestrial Multimedia Broadcasting [Topics in Wireless Communications], IEEE Communications Magazine, 48(5),119–127
  5. ^ "Korea's Terrestrial DMB: Germany to begin broadcast this May". ZDNet Korea. 2006-04-06. Retrieved 2010-06-17.
  6. ^ "picturephoning.com: DMB". Textually.org. Archived from the original on 2010-08-09. Retrieved 2010-06-17.
  7. ^ "South Korea : Social Media 답변 내용 : 악어새 – 리포트월드". Reportworld.co.kr. Archived from the original on 2009-08-17. Retrieved 2010-06-17.
  8. ^ a b c "The Origins and Future Prospects of Digital Television". Benton Foundation. 2008-12-23.
  9. ^ a b c Lea, William (1994). Video on demand: Research Paper 94/68. House of Commons Library. Retrieved 20 September 2019.
  10. ^ a b c Barbero, M.; Hofmann, H.; Wells, N. D. (14 November 1991). "DCT source coding and current implementations for HDTV". EBU Technical Review (251). European Broadcasting Union: 22–33. Retrieved 4 November 2019.
  11. ^ Meigs, James B. (June 1986). "Home Video: Get set for digital". Popular Mechanics. Vol. 163, no. 6. Hearst Magazines. p. 52. ISSN 0032-4558.
  12. ^ Bateman, Selby (April 1986). "New Technologies: The Converging Digital Universe". Compute!. No. 71. pp. 21-29 (26-8).
  13. ^ Barbero, M.; Stroppiana, M. (October 1992). "Data compression for HDTV transmission and distribution". IEE Colloquium on Applications of Video Compression in Broadcasting: 10/1–10/5.
  14. ^ Kim, Gary (June 11, 1990). "First All-Digital HDTV Developed by VideoCipher". No. Multichannel News.
  15. ^ Andrews, Edward (January 31, 1991). "Two Competitors in Pact on HDTV Plan". No. New York Times.
  16. ^ Barker, Paul. "Compressing the Future". No. October 5, 1990.
  17. ^ Santo, Brian (January 1, 1993). "FCC Urges 'Grand Alliance' for US HDTV". No. EE Times.
  18. ^ Andrews, Edmund (May 25, 1993). "Top Rivals Agree on Unified System for Advanced TV". No. New York Times.
  19. ^ Tayer, Marc (2015). Televisionaries. MediaTech Publishing. p. 102. ISBN 978-0-9863845-0-9.
  20. ^ Tayer, Marc (2015). Televisionaries. MediaTech Publishing. p. 144. ISBN 978-0-9863845-0-9.
  21. ^ Tayer, Marc (2015). Televisionaries. MediaTech Publishing. p. 146. ISBN 978-0-9863845-0-9.
  22. ^ "History of U.S. Satellite Broadcasting Company, Inc. – FundingUniverse". www.fundinguniverse.com. Retrieved 9 August 2018.
  23. ^ "Business Insider: Digital satellite TV has Indy roots". Retrieved 9 August 2018.
  24. ^ Tayer, Marc (2015). Televisionaries. MediaTech Publishing. pp. 157–161. ISBN 978-0-9863845-0-9. {{cite book}}: Cite has empty unknown parameter: |1= (help)
  25. ^ Ellis, Leslie (July 14, 1997). "MPEG Licensing Group Starts Road Show". No. Multichannel News.
  26. ^ "NextLevel signs cable deal - Dec. 17, 1997". money.cnn.com. Retrieved 9 August 2018.
  27. ^ "TCI faces big challenges - Aug. 15, 1996". money.cnn.com. Retrieved 9 August 2018.
  28. ^ "CANAL+ TECHNOLOGIES and the world's first digital terrestrial television service in the United Kingdom". Retrieved 9 August 2018.
  29. ^ Tayer, Marc. Televisionaries. MediaTech Publishing. pp. 226–249. ISBN 978-0-9863845-0-9.
  30. ^ Latest snapshots - Freeview/DTT bitrates Archived 2007-11-22 at the Wayback Machine (Mendip transmitter, UK)
  31. ^ "Why do ATSC channels need 6MHz of bandwidth when they're digital?". Signal Processing Stack Exchange. Retrieved 2025-07-06.
  32. ^ "17 U.S. Code § 1201 - Circumvention of copyright protection systems". LII / Legal Information Institute. Retrieved 2025-07-06.
  33. ^ "Frequently Asked Questions -- What Is Digital TV?". ABC News. Retrieved 2020-09-30.
  34. ^ "Transforming Digital TV Advertising with Interactive ChatGPT Technology: Enhancing User Engagement and Ad Effectiveness. AI Development in Digital TV. ChatGPT in Digital TV developers". devset.ai. Retrieved 2025-07-06.
  35. ^ Flack, Jason (2024-05-09). "T.V. Viewing Statistics: Exploring T.V. Viewing Statistics". Greater Collinwood. Retrieved 2025-07-06.
  36. ^ "Report ITU-R BT.2140-3 (05/2011)" (PDF). Archived (PDF) from the original on 10 June 2020.
  37. ^ "Digital TV: A Cringley Crash Course — Digital Vs. Analog". Pbs.org. Retrieved 2014-01-13.{{cite web}}: CS1 maint: deprecated archival service (link)
  38. ^ Le Dinh, Phuc-Tue; Patry, Jacques (February 24, 2006). "Video compression artifacts and MPEG noise reduction". Video Imaging DesignLine. Archived from the original on March 14, 2006. Retrieved April 30, 2010.
  39. ^ "Digital TV Info". Antenna Direct. 2013-09-25. Retrieved 2022-07-22.
  40. ^ "Steering clear of the digital cliff". Connected Magazine. 2010-03-01. Retrieved 2024-01-05.
  41. ^ North Tonawanda: council discusses future TV disposal Archived 2009-01-31 at the Wayback Machine, Neale Gulley, Tonawanda News, January 27, 2009
  42. ^ Trashing the tube: Digital conversion may spark glut of toxic waste, Jennifer Chambers, Detroit News, January 23, 2009
  43. ^ Old Toxic TVs Cause Problems, USA TODAY, January 27, 2009
  44. ^ Unloading that old TV not quite so simple, Lee Bergquist, Milwaukee Journal-Sentinel, January 23, 2009

Further reading

Wikimedia Commons logo
Wikimedia Commons has media related to Digital television.
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.