Digital cable is a generic term for any type of cable television distribution using digital video compression or distribution. The technology was originally developed by Motorola.

Background

In 1989, General Instrument (which was later acquired by Motorola) demonstrated that it was possible to convert an analog cable signal to digital and transmit it in a standard 6-MHz television channel. In the 1990s cable providers began to invest heavily in new digital based distribution systems. Increased competition and programming choices from Direct-broadcast satellite services such as DirecTV, Dish Network, and PrimeStar caused cable providers to seek new ways to provide more programming. Customers were increasingly interested in more channels, pay-per-view programming, digital music services, and high speed internet services. By 2000, most cable providers in the US were offering some form of digital services to their customers.

Digital cable technology has allowed cable providers to compress video channels so that they take up less frequency space and to offer various two-way communication capabilities. This has enabled digital cable providers to offer more channels, video on demand services (without use of a telephone line), telephone services, high speed internet services, and interactive television services. In addition, digital cable technology allows for error correction to ensure the quality of the received signal and uses a secure digital distribution system (i.e. a secure encrypted signal to prevent eavesdropping and theft of service)

Most digital cable providers use QAM for video services and DOCSIS standards for data services. Some providers have also begun to roll out video services using IPTV or Switched video technologies.

Channels

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 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.

The addition of this capability complicates the notion of a "channel" in digital cable (as well as in over-the-air ATSC digital broadcasts). The formal names for the two numbers that now identify a channel are the physical channel and the subchannel.

The physical channel is a number corresponding to a specific 6 MHz frequency range. See: North American cable television frequencies.

The subchannel 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 (since the bandwidth must be divided among all the subchannels).

There are two ways providers try to make this easier for consumers. The first, accomplished through PSIP, 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.

The second (also accomplished through PSIP) is where, in an effort to hide subchannels entirely, many cable companies map virtual channel 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, 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".

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 mapping and can communicate that to the set-top box.

Preserving Bandwidth

Digital cable has allowed for out of market television stations to be removed from the basic cable lineup from Channels 2 through 13. They would be moved over to digital cable channels 100 and above for bandwidth preservation. Currently, Comcast Cable outlets in New Jersey and Virginia are adapting this in significantly viewed counties that are bordering nearby television markets.

Technical information

The standard for signal transmission over digital cable television systems in the United States is now fixed as both ''64-QAM'' and ''256-QAM'' (Quadrature Amplitude Modulation), which is specified in SCTE 07, and is part of the DVB standard (but not ATSC). This method carries 38.47 Mbit/s using 256-QAM on a 6 MHz channel, which can carry nearly two full ATSC 19.39 Mbit/s transport streams. Each 6-MHz channel is typically used to carry 7–12 digital SDTV channels (256-QAM, MPEG2 MP/ML streams of 3–5 Mbit/s). On many boxes with QAM tuners (most notably the DVR boxes), High Definition versions of local channels and some cable channels are available.

Digital Cable allows for the broadcast of EDTV (480p) as well as HDTV (720p, 1080i, and eventually 1080p). By contrast, analog cable transmits programs solely in the 480i format (the lowest television definition in use today).

The ATSC standards include a provision for 16-VSB transmission over cable at 38.4 Mbit/s, but the encoding has not yet gained wide acceptance. Some MATV systems may carry 8-VSB and QAM signals, mostly in apartment buildings and similar facilities that use a combination of terrestrial antennas and cable distribution sources (such as HITS or "Headend in the Sky", a unit of Comcast that delivers digital channels by satellite to small cable systems).

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 UHF broadcast channels with the same number, as seen in North American cable television frequencies.) 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).

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 CableCARDs to customers that request them.

See also

Digital television

QAM Tuner

CableCARD

Tru2way

Cable television in the United States

Direct-broadcast satellite

Significantly viewed

References

External links

National Cable and Telecommunications Association - Digital Cable

Digital cable & Digital house

US CATV Channels and Frequencies table (up to channel 78)

US CATV Channels and Frequencies table (comprehensive)

* Category:Television terminology

Alex Boyé is a British-born Latter-day Saint singer and actor of Nigerian descent.

Boyé was born in London, England. He joined The Church of Jesus Christ of Latter-day Saints (LDS Church) at age 16. He served as a missionary in the England Bristol Mission. He was then the lead singer in the boy band Awesome, which sold over 500,000 CDs while on contract with Universal Records Europe. In 1999 Boye left the band to begin a solo career, releasing his first solo album in 2000 which made it to number 12 on the European charts. In 2000 Boyé moved to Utah. He has since been involved in many musical and theatrical productions.

Boyé has been an actor for the Hale Center Theatre in multiple productions and has played the role of Frederick Douglass in Frank Wildhorn's ''Civil War'' both at Hale Center and at Rogers Memorial Theatre in Centerville, Utah. He played the role of Aminadab in Lightsone Films' production of ''David and Goliath''. He was a member of the Mormon Tabernacle Choir for about five years, but appears to have now gone to a solo career. Recently he participated as a featured soloist in a concert connected with the rededication of the St. George Catholic Church. In 2005 Boye received an award from the LDS Booksellers Association for his album "Testimony".

Boyé married his wife Julie in the Salt Lake Temple.

Boyé's hit single "Crazy For You" has been played by radio stations nationwide. His recent ''Be Still My Soul: Classic Hymns and Folksongs'' has also been a major success.

He also sang "Born To Be A Scout", the feature song from the B-movie "Scout Camp". Songs by Boye have also appeared in other movies such as ''Baptists at Our Barbecue'' and ''Church Ball''.

Notes

Sources

''Mormon Times'' Dec. 11, 2009

''Denver Post'' article on Boye

Bio from Boyé's website

LDS Musicworld entry on Boyé

''St. Louis American'', July 26, 2008

Article on Boyé from 2006

discogs entry for Boye

''Mormons in Music'' bio of Boye

External links

Official website

The Boye Family Jewels (blog)

Category:20th-century Mormon missionaries Category:Actors from Utah Category:British people of Nigerian descent Category:Converts to Mormonism Category:English emigrants to the United States Category:English Latter Day Saints Category:English Mormon missionaries Category:English male singers Category:English musical theatre actors Category:Latter Day Saint music Category:Living people Category:Members of the Mormon Tabernacle Choir Category:Musicians from Utah Category:Mormon missionaries in England