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204:) demonstrated that it was possible to use digital compression to deliver high quality HDTV in a standard 6 MHz television channel. Using the same technology General Instrument (GI) demonstrated the digital transmission of multiple high quality standard definition programs in a 6 MHz cable channel.
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numbers to underlying physical and sub-channels. For example, a cable company might call channel 5-1 "channel 732" and channel 5-2 "channel 733". This also allows the cable company to change the frequency of a channel without changing what the customer sees as a channel number. In such arrangements,
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Digital cable technology can allow many TV channels to occupy the frequency space that would normally be occupied by a single analog cable TV channel. The number of channels placed on a single analog frequency depends on the compression used. Many cable providers are able to fit about 10 digital SD
319:
In theory, a set-top box can decode the PSIP information from every channel it receives and use that information to build the mapping between QAM channel and virtual channel. However, cable companies do not always reliably transmit PSIP information. Alternatively, CableCards receive the channel
153:. The technology was first developed by General Instrument. By 2000, most cable companies offered digital features, eventually replacing their previous analog-based cable by the mid 2010s. During the late 2000s, broadcast television converted to the digital
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channels or 2 digital HD channels on a single analog channel frequency. Some providers are able to squeeze more channels onto a single frequency with higher compression, but often this can cause the video quality of the channel to degrade.
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is a logical channel of data within the physical channel. Technically there can be up to 1024 subchannels in a physical channel, though in practice only a few are used (as the bandwidth must be divided among all the subchannels).
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In the 1990s, cable providers began to invest heavily in this new multi-channel digital TV technology to expand the number of channels and services available to subscribers. Increased competition and programming choices from
429:.) Between 552 and 750 MHz, there is space for 33 6-MHz channels (231–396 SDTV channels); when going all the way to 864 MHz, there is space for 52 6-MHz channels (364–624 SDTV channels).
308:, is where program and channel information is broadcast along with the video, allowing the consumer's decoder (set-top box or display) to automatically identify the many channels and subchannels.
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the physical/sub-channel numbers are called the "QAM channel", and the alternative channel designation is called the "mapped channel", "virtual channel", or simply "channel".
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programming, digital music services, and high speed internet services. By 2000, most cable providers in the US were offering some form of digital cable TV to their customers.
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to ensure the integrity of the received signal and uses a secure digital distribution system (i.e. a secure encrypted signal to prevent eavesdropping and theft of service.)
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Digital cable channels typically are allocated above 552 MHz, the upper frequency of cable channel 78. (Cable channels above channel 13 are at lower frequencies than
387:(480p) as well as HDTV (720p, 1080i, and 1080p). By contrast, analog cable transmits programs solely in the 480i format (the lowest television definition in use today).
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In the U.S., digital cable systems with 750 MHz or greater activated channel capacity are required to comply with a set of SCTE and CEA standards, and to provide
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and QAM signals, mostly in apartment buildings and similar facilities that use a combination of terrestrial antennas and cable distribution sources (such as
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caused cable providers to seek new ways to provide more programming. Customers were increasingly interested in more channels,
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The second (also accomplished through PSIP) is where, in an effort to hide subchannels entirely, many cable companies map
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The addition of this capability complicates the notion of a "channel" in digital cable (as well as in over-the-air
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Digital cable technology has allowed cable providers to compress video channels so that they take up less
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transmission over cable at 38.4 Mbit/s, but the encoding has not yet gained wide acceptance. Some
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There are two ways providers try to make this easier for consumers. The first, accomplished through
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channel, which can carry nearly two full ATSC 19.39 Mbit/s transport streams. Each 6-MHz
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The physical channel is a number corresponding to a specific 6 MHz frequency range. See:
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standards for data services. Some providers have also begun to roll out video services using
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The standard for signal transmission over digital cable television systems in the
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Distribution of cable television using digital data and video compression
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that delivers digital channels by satellite to small cable systems).
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standard, which was incompatible with existing analog cable systems.
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capabilities. This has enabled providers to offer more channels,
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537:"History of General Instrument Corporation – FundingUniverse"
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MP/ML streams of 3–5 Mbit/s). On many boxes with
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US CATV Channels and
Frequencies table (up to channel 78)
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164:, digital cable systems provide more services such as
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mapping and can communicate that to the set-top box.
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broadcast channels with the same number, as seen in
60:. Unsourced material may be challenged and removed.
563:"Your Guide to Free Broadcast Digital Television"
1333:
392:Advanced Television Systems Committee standards
364:is typically used to carry 7–12 digital
659:
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427:North American cable television frequencies
291:North American cable television frequencies
666:
652:
383:Digital cable allows for the broadcast of
120:Learn how and when to remove this message
323:
243:services that don't require a separate
14:
1334:
1119:Downloadable Conditional Access System
978:Template:American broadcast television
983:Template:Canadian television networks
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451:Cable television in the United States
972:Digital multicast television network
58:adding citations to reliable sources
29:
24:
1074:Interactive-digital-cable-ready TV
184:which occurred in analog systems.
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791:U.S. Converter Box Coupon Program
622:Digital cable & Digital house
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254:Most digital cable providers use
180:, which reduced the incidence of
176:. Most digital cable signals are
743:Metropolitan Television Alliance
436:to customers that request them.
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716:Distributed transmission system
342:quadrature amplitude modulation
45:needs additional citations for
1079:OpenCable Application Platform
588:"How Digital Television Works"
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513:. motorola.com. Archived from
511:"Decades of proven experience"
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1:
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786:Digital television adapter
632:February 24, 2020, at the
466:Direct-broadcast satellite
210:direct-broadcast satellite
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1296:Channel protection ratios
1286:Active Format Description
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1029:wireless spectrum auction
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344:), which is specified in
160:In addition to providing
944:Serial digital interface
932:Ultra high-definition TV
776:Digital channel election
766:All-Channel Receiver Act
394:include a provision for
174:cable telephone services
18:Digital cable television
1306:Hierarchical modulation
813:Digital video recorders
541:www.fundinguniverse.com
348:07, and is part of the
284:ATSC digital broadcasts
258:for video services and
182:cable television piracy
1347:Television terminology
1062:Digital-cable-ready TV
893:Enhanced-definition TV
876:Standard-definition TV
446:Cable Internet access
332:is now fixed as both
324:Technical information
237:two-way communication
170:cable internet access
162:high-definition video
1316:Standards conversion
693:Digital broadcasting
486:Significantly viewed
54:improve this article
992:National deployment
706:Digital subchannels
368:channels (256-QAM,
1173:Telus Satellite TV
1156:GlobeCast World TV
910:High-definition TV
803:Analog passthrough
758:Digital switchover
675:Digital television
594:. January 10, 2001
461:Digital television
412:Headend in the Sky
402:systems may carry
376:(most notably the
352:standard (but not
194:General Instrument
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1311:Pirate decryption
1281:14:9 aspect ratio
1200:Claro Puerto Rico
1169:Bell Satellite TV
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822:Digital standards
731:National Datacast
212:services such as
200:and now owned by
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16:(Redirected from
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249:error correction
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110:November 2019
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71: –
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65:Find sources:
59:
55:
49:
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43:This article
41:
37:
32:
31:
19:
1255:Bell Fibe TV
1185:DigiCipher 2
1151:Dish Network
1138:Satellite TV
1053:
596:. Retrieved
591:
582:
570:. Retrieved
566:
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544:. Retrieved
540:
531:
519:. Retrieved
515:the original
505:
476:DigiCipher 2
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407:
389:
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226:pay-per-view
218:Dish Network
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166:pay-per-view
159:
147:digital data
139:distribution
134:
133:
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64:
52:Please help
47:verification
44:
1195:Shaw Direct
1178:Dish México
1161:Free-to-air
796:legislation
736:UpdateLogic
721:Datacasting
701:ATSC tuners
684:Terrestrial
598:December 3,
572:December 3,
546:December 3,
202:ARRIS Group
1336:Categories
1250:U-verse TV
1230:Sky Mexico
1225:Sky Brazil
1091:Must-carry
1086:Encryption
1067:QAM tuners
1024:transition
726:Guide Plus
497:References
434:CableCARDs
374:QAM tuners
298:subchannel
80:newspapers
1301:HDTV blur
1114:CableCARD
869:full list
771:SAFER Act
481:QAM Tuner
456:CableCARD
233:bandwidth
222:PrimeStar
192:In 1990,
178:encrypted
1164:receiver
839:ATSC-M/H
630:Archived
521:March 5,
440:See also
274:Channels
198:Motorola
1260:FibreOP
1216:DirecTV
1124:Tru2way
954:CEA-909
491:Tru2way
416:Comcast
362:channel
338:256-QAM
214:DirecTV
188:History
137:is the
94:scholar
1211:DVB-S2
1109:AllVid
1009:Mexico
1004:Canada
396:16-VSB
334:64-QAM
260:DOCSIS
220:, and
145:using
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89:
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1146:DVB-S
1045:Cable
937:2160p
925:1080p
920:1080i
854:E-VSB
849:A-VSB
471:DVB-C
404:8-VSB
400:SMATV
370:MPEG2
101:JSTOR
87:books
1242:IPTV
1221:Vrio
1190:4DTV
1019:HDTV
976:see
915:720p
903:576p
898:480p
886:576i
881:480i
864:PMCP
859:PSIP
844:8VSB
834:ATSC
600:2020
574:2020
567:AARP
548:2020
523:2008
410:or "
408:HITS
390:The
385:EDTV
366:SDTV
354:ATSC
346:SCTE
336:and
306:PSIP
296:The
264:IPTV
172:and
155:HDTV
149:and
73:news
423:UHF
378:DVR
358:MHz
350:DVB
266:or
256:QAM
141:of
56:by
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340:(
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108:(
98:·
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20:)
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