Friday, October 2, 2009
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Results 1-24 of 24 companies
*
DIRECTV Inc
El Segundo, California
The DIRECTV Group, Inc. is a provider of digital television entertainment in the United States and Latin America. The business segments, DIRECTV U.S. and DIRECTV Latin America are engaged in acquiring, promoting, selling and/or distributing digital entertainment programming through... more
*
DISH Network Corporation
Englewood, Colorado
DISH Network Corporation is a provider of satellite delivered digital television to customers across the United States. DISH Network services include hundreds of video, audio and data channels, interactive television channels, digital video recording, high definition television,... more
*
EchoStar Communications Corporation
Inglewood, Colorado
EchoStar Corporation (EchoStar), formerly EchoStar Holding Corporation, will operate two primary businesses: digital set-top box business and a fixed satellite services business. EchoStar had a spin-off from DISH Network on January 1, 2008. The Company’s set-top box business designs,... more
*
Intelsat , Ltd.
Washington , Dc, District of Columbia
Intelsat Corporation is a provider of fixed satellite services worldwide and a provider of these services to each of the media and network services sectors. The Company provides service on a global fleet of 26 satellites that are integrated with 27 other satellites owned by other... more
*
GlobeCast
London, United Kingdom
GlobeCast, a subsidiary of France Telecom, is the leading global provider of content management and worldwide transmission services for professional broadcast delivery. The company operates a secure global satellite and fibre network to manage and transport 10 million hours of video... more
*
Telesat
Gloucester, Ontario, Canada
Telesat is a pioneer and world leader in satellite operations and systems management. The company made history in 1972 with the launch of the first Canadian commercial communications satellite in geostationary orbit. Today, Telesat competes with other top international satellite fleets in... more
*
Arqiva Limited
Winchester, Hampshire, United Kingdom
Arqiva has a 50-year history in transmission and has helped pioneer the technologies of the digital age. 22 million UK homes receive ITV, Channel 4 and Five via Arqiva's national transmitter networks. The company also provides transmission for most UK independent radio stations, both... more
*
Bell ExpressVu LP
North York, Ontario, Canada
Launched in September 1997, Bell ExpressVu is the largest and fastest growing direct-to-home (DTH) television company in Canada and the fifth largest broadcast distributor in the country with over 725,000 subscribers as of December 2000. Currently, the company offers more than 200 video... more
*
SES ASTRA
Austin, Texas
SES ASTRA operates the ASTRA Satellite System, offering a comprehensive portfolio of broadcast and broadband solutions for customers in Europe and beyond. ASTRA broadcasts television and radio programmes directly to millions of homes, and provides internet access and network services to... more
*
SES GLOBAL company
SES GLOBAL (Euronext Paris, Luxembourg Stock Exchange: SESG) wholly owns three market-leading satellite operators, SES ASTRA in Europe, SES AMERICOM in North America, and SES NEW SKIES, which provide global coverage and connectivity. The Company also holds strategic participations in... more
*
Sentech
Carrollton, Texas
Sentech has been at the leading edge of communication technology, pioneering the provisioning of broadcast signal distribution services. Sentech, a commercially operated, state-owned enterprise, is the largest signal distributor for broadcasting in Africa, transmitting programs for... more
*
Shaw Communications Inc
Calgary, Alberta, Canada
Shaw Communications Inc. is a communications company whose core business is providing broadband cable television, Internet, Digital Phone, telecommunications services (through Shaw Business Solutions) and satellite direct-to-home services (through Star Choice) to approximately 3.3 million... more
*
Arabsat
Backed by the 21 member countries of the Arab League, and with its 30-year heritage of continuous operations, Arabsat offers the Arab world an unrivalled range of satellite-based communications services such as Direct-to-Home Television and Radio, telephony, Internet and direct Broadband... more
*
MEASAT
*
Tata Sky Ltd.
Tata Sky Ltd., a joint venture of TATA and STAR, is committed to build a state-of-the-art Digital infrastructure for Pay Television in India. Tata Sky plans to introduce a nationwide Direct-to-Home (DTH) service that would allow it to reach every Indian home, however remote it may be. The... more
*
AlphaStar International Inc
Greenwich, Connecticut
AlphaStar is a 21st Century globally integrated Communications Company offering continuous full-motion high definition video, in IP multicasting and streaming formats, television and other multimedia programming services to the Internet through its uniquely positioned, high-bandwidth... more
*
Astro
Astro is Malaysia's leading multimedia broadcaster and producer of Malay, Chinese, Indian and English language programming content. It owns and operates the only direct-to-home satellite TV service with access to some 10 million viewers in over 2 million homes, representing 38% of TV... more
*
Pittsburgh International Telecommunications Inc
Pittsburgh, Pennsylvania
Pittsburgh International Telecommunications was established in 1983 as Mobile Satellite Communications, Inc. in Pittsburgh, Pennsylvania. The company provided mobile satellite uplinking services and owned and operated one C-Band transportable vehicle, which serviced the major television... more
*
ProtoStar LTD
San Francisco, California
ProtoStar is an Asian satellite services operator that was formed to acquire, launch and operate high-power geostationary satellites to lease capacity to Asian DTH and broadband service providers. The technical characteristics of its satellites and the configuration of the satellite... more
*
ASC Enterprises Limited
Lexington, Kentucky
*
Super Value Channel Inc
Pomona, California
SVC sells a variety of consumer products through DTH satellite TV, Cable TV, and over the internet. With full-scale TV production facility and multi-lingual "TV Shopping Experts" who may speak the ethnic languages to better service the customers, SVC is capable to broadcasting informative... more
*
SET Discovery Ltd.
SET Discovery Private Limited is a joint venture between SET India Pvt. Ltd. and Discovery Communications India. The company was set up in April 2002. Today, the company distributes 15 leading channels under the brand name of TheOneAlliance to over 61 million homes spread over 4000 cities... more
*
Atlanta DTH , Inc.
City Of Industry, California
Established in 1993, Atlanta DTH, Inc. is a leading supplier in the DTH satellite industry. We provide a complete product line of DTH satellite equipment such as IRD and LNBF, as well as customer-driven satellite network services and customer management system. ADTH's RV division... more
*
Cyfrowy Polsat S.A.
Launched in 1999, Cyfrowy Polsat offers today 35 television channels in the Polish language and five radio channels as well as hundreds of international Free-To-Air channels. The platform also offers interactive applications, such as TV banking, weather forecasts, SMS Chat, e-mail and... more
Posted by ramkumar at 9:26 AM 0 comments
Advanced Search
Refine Search
You searched for:
Industry Keywords
Refine by:
Company Name
Location
Advanced Search
Sub Categories
Narrow By:
Digital Dth
Dth Bit
Dth Bit Manufacturing
Dth Broadcasting
Dth Drill
Dth Hammer
Dth Hammer Manufacturing
Dth Operator
Dth Platform
Dth Platform Operator
Dth Satellite
Dth Satellite Space
Dth Satellite Television
Dth Service Provider
Tv Dth
Expand By:
Cable Programming
Digital Satellite
Digital Satellite Television
Direct Broadcast Satellite
DIRECTV Programming
Local Cable
Main Cable
Pay TV
Satellite Broadcasting
Satellite Pay TV
Satellite TV
Teleports
Sort By: Relevance (Default) Company Name Ascending Company Name Descending Revenue Results 1-24 of 24 companies
DIRECTV Inc
El Segundo, California
The DIRECTV Group, Inc. is a provider of digital television entertainment in the United States and Latin America. The business segments, DIRECTV U.S. and DIRECTV Latin America are engaged in acquiring, promoting, selling and/or distributing digital entertainment programming through... more
DISH Network Corporation
Englewood, Colorado
DISH Network Corporation is a provider of satellite delivered digital television to customers across the United States. DISH Network services include hundreds of video, audio and data channels, interactive television channels, digital video recording, high definition television,... more
EchoStar Communications Corporation
Inglewood, Colorado
EchoStar Corporation (EchoStar), formerly EchoStar Holding Corporation, will operate two primary businesses: digital set-top box business and a fixed satellite services business. EchoStar had a spin-off from DISH Network on January 1, 2008. The Company’s set-top box business designs,... more
Intelsat , Ltd.
Washington , Dc, District of Columbia
Intelsat Corporation is a provider of fixed satellite services worldwide and a provider of these services to each of the media and network services sectors. The Company provides service on a global fleet of 26 satellites that are integrated with 27 other satellites owned by other... more
GlobeCast
London, United Kingdom
GlobeCast, a subsidiary of France Telecom, is the leading global provider of content management and worldwide transmission services for professional broadcast delivery. The company operates a secure global satellite and fibre network to manage and transport 10 million hours of video... more
Telesat
Gloucester, Ontario, Canada
Telesat is a pioneer and world leader in satellite operations and systems management. The company made history in 1972 with the launch of the first Canadian commercial communications satellite in geostationary orbit. Today, Telesat competes with other top international satellite fleets in... more
Arqiva Limited
Winchester, Hampshire, United Kingdom
Arqiva has a 50-year history in transmission and has helped pioneer the technologies of the digital age. 22 million UK homes receive ITV, Channel 4 and Five via Arqiva's national transmitter networks. The company also provides transmission for most UK independent radio stations, both... more
Bell ExpressVu LP
North York, Ontario, Canada
Launched in September 1997, Bell ExpressVu is the largest and fastest growing direct-to-home (DTH) television company in Canada and the fifth largest broadcast distributor in the country with over 725,000 subscribers as of December 2000. Currently, the company offers more than 200 video... more
SES ASTRA
Austin, Texas
SES ASTRA operates the ASTRA Satellite System, offering a comprehensive portfolio of broadcast and broadband solutions for customers in Europe and beyond. ASTRA broadcasts television and radio programmes directly to millions of homes, and provides internet access and network services to... more
SES GLOBAL company
SES GLOBAL (Euronext Paris, Luxembourg Stock Exchange: SESG) wholly owns three market-leading satellite operators, SES ASTRA in Europe, SES AMERICOM in North America, and SES NEW SKIES, which provide global coverage and connectivity. The Company also holds strategic participations in... more
Sentech
Carrollton, Texas
Sentech has been at the leading edge of communication technology, pioneering the provisioning of broadcast signal distribution services. Sentech, a commercially operated, state-owned enterprise, is the largest signal distributor for broadcasting in Africa, transmitting programs for... more
Shaw Communications Inc
Calgary, Alberta, Canada
Shaw Communications Inc. is a communications company whose core business is providing broadband cable television, Internet, Digital Phone, telecommunications services (through Shaw Business Solutions) and satellite direct-to-home services (through Star Choice) to approximately 3.3 million... more
Arabsat
Backed by the 21 member countries of the Arab League, and with its 30-year heritage of continuous operations, Arabsat offers the Arab world an unrivalled range of satellite-based communications services such as Direct-to-Home Television and Radio, telephony, Internet and direct Broadband... more
MEASAT
Tata Sky Ltd.
Tata Sky Ltd., a joint venture of TATA and STAR, is committed to build a state-of-the-art Digital infrastructure for Pay Television in India. Tata Sky plans to introduce a nationwide Direct-to-Home (DTH) service that would allow it to reach every Indian home, however remote it may be. The... more
AlphaStar International Inc
Greenwich, Connecticut
AlphaStar is a 21st Century globally integrated Communications Company offering continuous full-motion high definition video, in IP multicasting and streaming formats, television and other multimedia programming services to the Internet through its uniquely positioned, high-bandwidth... more
Astro
Astro is Malaysia's leading multimedia broadcaster and producer of Malay, Chinese, Indian and English language programming content. It owns and operates the only direct-to-home satellite TV service with access to some 10 million viewers in over 2 million homes, representing 38% of TV... more
Pittsburgh International Telecommunications Inc
Pittsburgh, Pennsylvania
Pittsburgh International Telecommunications was established in 1983 as Mobile Satellite Communications, Inc. in Pittsburgh, Pennsylvania. The company provided mobile satellite uplinking services and owned and operated one C-Band transportable vehicle, which serviced the major television... more
ProtoStar LTD
San Francisco, California
ProtoStar is an Asian satellite services operator that was formed to acquire, launch and operate high-power geostationary satellites to lease capacity to Asian DTH and broadband service providers. The technical characteristics of its satellites and the configuration of the satellite... more
ASC Enterprises Limited
Lexington, Kentucky
Super Value Channel Inc
Pomona, California
SVC sells a variety of consumer products through DTH satellite TV, Cable TV, and over the internet. With full-scale TV production facility and multi-lingual "TV Shopping Experts" who may speak the ethnic languages to better service the customers, SVC is capable to broadcasting informative... more
SET Discovery Ltd.
SET Discovery Private Limited is a joint venture between SET India Pvt. Ltd. and Discovery Communications India. The company was set up in April 2002. Today, the company distributes 15 leading channels under the brand name of TheOneAlliance to over 61 million homes spread over 4000 cities... more
Atlanta DTH , Inc.
City Of Industry, California
Established in 1993, Atlanta DTH, Inc. is a leading supplier in the DTH satellite industry. We provide a complete product line of DTH satellite equipment such as IRD and LNBF, as well as customer-driven satellite network services and customer management system. ADTH's RV division... more
Cyfrowy Polsat S.A.
Launched in 1999, Cyfrowy Polsat offers today 35 television channels in the Polish language and five radio channels as well as hundreds of international Free-To-Air channels. The platform also offers interactive applications, such as TV banking, weather forecasts, SMS Chat, e-mail and... more
Posted by ramkumar at 9:26 AM 0 comments
This article contains weasel words, vague phrasing that often accompanies biased or unverifiable information. Such statements should be clarified or removed. (March 2009)
Satellite television is television delivered by the means of communications satellite and received by a satellite dish and set-top box. In many areas of the world it provides a wide range of channels and services, often to areas that are not serviced by terrestrial or cable providers.
Contents
[hide]
1 History
2 Technology
3 Standards
4 Categories of usage
4.1 Direct broadcast via satellite
4.2 Television receive-only
4.2.1 Direct to home television
4.2.2 Programming
4.2.3 Broadcasting centers
4.2.4 Encryption and transmission
4.2.5 The dish
4.2.6 The receiver
5 Satellite television by region and country
5.1 United States
5.2 India
5.3 Canada
5.4 United Kingdom
6 See also
7 References
8 External links
[edit] History
The first satellite television signal was relayed from Europe to the Telstar satellite over North America in 1962. The first geosynchronous communication satellite, Syncom 2 was launched in 1963. The world's first commercial communication satellite, called Intelsat I (nicknamed Early Bird), was launched into synchronous orbit on April 6, 1965. The first national network of satellite television, called Orbita, was created in Soviet Union in 1967, and was based on the principle of using the highly elliptical Molniya satellite for re-broadcasting and delivering of TV signal to ground downlink stations. The first domestic North American satellite to carry television was Canada’s geostationary Anik 1, which was launched in 1972.[1] ATS-6, the world's first experimental educational and Direct Broadcast Satellite, was launched in 1974. The first Soviet geostationary satellite to carry Direct-To-Home television, called Ekran, was launched in 1976.
[edit] Technology
Satellites used for television signals are generally in either naturally highly elliptical (with inclination of +/-63.4 degrees and orbital period of about 12 hours, also known as Molniya orbit) or geostationary orbit 37,000 km (22,300 miles) above the earth’s equator.
Satellite television, like other communications relayed by satellite, starts with a transmitting antenna located at an uplink facility. Uplink satellite dishes are very large, as much as 9 to 12 meters (30 to 40 feet) in diameter. The increased diameter results in more accurate aiming and increased signal strength at the satellite. The uplink dish is pointed toward a specific satellite and the uplinked signals are transmitted within a specific frequency range, so as to be received by one of the transponders tuned to that frequency range aboard that satellite. The transponder 'retransmits' the signals back to Earth but at a different frequency band (a process known as translation, used to avoid interference with the uplink signal), typically in the C-band (4–8 GHz) or Ku-band (12–18 GHz) or both. The leg of the signal path from the satellite to the receiving Earth station is called the downlink.
A typical satellite has up to 32 transponders for Ku-band and up to 24 for a C-band only satellite, or more for hybrid satellites. Typical transponders each have a bandwidth between 27 MHz and 50 MHz. Each geo-stationary C-band satellite needs to be spaced 2 degrees from the next satellite (to avoid interference). For Ku the spacing can be 1 degree. This means that there is an upper limit of 360/2 = 180 geostationary C-band satellites and 360/1 = 360 geostationary Ku-band satellites. C-band transmission is susceptible to terrestrial interference while Ku-band transmission is affected by rain (as water is an excellent absorber of microwaves at this particular frequency).
The downlinked satellite signal, quite weak after traveling the great distance (see inverse-square law), is collected by a parabolic receiving dish, which reflects the weak signal to the dish’s focal point. Mounted on brackets at the dish's focal point is a device called a feedhorn. This feedhorn is essentially the flared front-end of a section of waveguide that gathers the signals at or near the focal point and 'conducts' them to a probe or pickup connected to a low-noise block downconverter or LNB. The LNB amplifies the relatively weak signals, filters the block of frequencies in which the satellite TV signals are transmitted, and converts the block of frequencies to a lower frequency range in the L-band range. The evolution of LNBs was one of necessity and invention.
The original C-Band satellite TV systems used a Low Noise Amplifier connected to the feedhorn at the focal point of the dish. The amplified signal was then fed via very expensive and sometimes 50 ohm impedance gas filled hardline coaxial cable to an indoor receiver or, in other designs, fed to a downconverter (a mixer and a voltage tuned oscillator with some filter circuitry) for downconversion to an intermediate frequency. The channel selection was controlled, typically by a voltage tuned oscillator with the tuning voltage being fed via a separate cable to the headend. But this design evolved.
Designs for microstrip based converters for Amateur Radio frequencies were adapted for the 4 GHz C-Band. Central to these designs was concept of block downconversion of a range of frequencies to a lower, and technologically more easily handled block of frequencies (intermediate frequency).
The advantages of using an LNB are that cheaper cable could be used to connect the indoor receiver with the satellite TV dish and LNB, and that the technology for handling the signal at L-Band and UHF was far cheaper than that for handling the signal at C-Band frequencies. The shift to cheaper technology from the 50 Ohm impedance cable and N-Connectors of the early C-Band systems to the cheaper 75 Ohm technology and F-Connectors allowed the early satellite TV receivers to use, what were in reality, modified UHF TV tuners which selected the satellite television channel for down conversion to another lower intermediate frequency centered on 70 MHz where it was demodulated. This shift allowed the satellite television DTH industry to change from being a largely hobbyist one where receivers were built in low numbers and complete systems were expensive (costing thousands of Dollars) to a far more commercial one of mass production.
Direct broadcast satellite dishes are fitted with an LNBF, which integrates the feedhorn with the LNB.
The satellite receiver demodulates and converts the signals to the desired form (outputs for television, audio, data, etc.). Sometimes, the receiver includes the capability to unscramble or decrypt; the receiver is then called an Integrated receiver/decoder or IRD. The cable connecting the receiver to the LNBF or LNB must be of the low loss type RG-6, quad shield RG-6 or RG-11, etc. It cannot be standard RG-59.
[edit] Standards
Analog television distributed via satellite is usually sent scrambled or unscrambled in NTSC, PAL, or SECAM television broadcast standards. The analog signal is frequency modulated and is converted from an FM signal to what is referred to as baseband. This baseband comprises the video signal and the audio subcarrier(s). The audio subcarrier is further demodulated to provide a raw audio signal.
If the signal is a digitized television signal or multiplex of signals, it is typically QPSK.
In general, digital television, including that transmitted via satellites, are generally based on open standards such as MPEG and DVB-S.
The conditional access encryption/scrambling methods include BISS, Conax, Digicipher, Irdeto, Nagravision, PowerVu, Viaccess, Videocipher, and VideoGuard. Many conditional access systems have been compromised.
[edit] Categories of usage
There are three primary types of satellite television usage: reception direct by the viewer, reception by local television affiliates, or reception by headends for distribution across terrestrial cable systems.
Direct to the viewer reception includes direct broadcast satellite or DBS and television receive-only or TVRO, both used for homes and businesses including hotels, etc.
Friday, October 2, 2009
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Sort By:
Results 1-24 of 24 companies
*
DIRECTV Inc
El Segundo, California
The DIRECTV Group, Inc. is a provider of digital television entertainment in the United States and Latin America. The business segments, DIRECTV U.S. and DIRECTV Latin America are engaged in acquiring, promoting, selling and/or distributing digital entertainment programming through... more
*
DISH Network Corporation
Englewood, Colorado
DISH Network Corporation is a provider of satellite delivered digital television to customers across the United States. DISH Network services include hundreds of video, audio and data channels, interactive television channels, digital video recording, high definition television,... more
*
EchoStar Communications Corporation
Inglewood, Colorado
EchoStar Corporation (EchoStar), formerly EchoStar Holding Corporation, will operate two primary businesses: digital set-top box business and a fixed satellite services business. EchoStar had a spin-off from DISH Network on January 1, 2008. The Company’s set-top box business designs,... more
*
Intelsat , Ltd.
Washington , Dc, District of Columbia
Intelsat Corporation is a provider of fixed satellite services worldwide and a provider of these services to each of the media and network services sectors. The Company provides service on a global fleet of 26 satellites that are integrated with 27 other satellites owned by other... more
*
GlobeCast
London, United Kingdom
GlobeCast, a subsidiary of France Telecom, is the leading global provider of content management and worldwide transmission services for professional broadcast delivery. The company operates a secure global satellite and fibre network to manage and transport 10 million hours of video... more
*
Telesat
Gloucester, Ontario, Canada
Telesat is a pioneer and world leader in satellite operations and systems management. The company made history in 1972 with the launch of the first Canadian commercial communications satellite in geostationary orbit. Today, Telesat competes with other top international satellite fleets in... more
*
Arqiva Limited
Winchester, Hampshire, United Kingdom
Arqiva has a 50-year history in transmission and has helped pioneer the technologies of the digital age. 22 million UK homes receive ITV, Channel 4 and Five via Arqiva's national transmitter networks. The company also provides transmission for most UK independent radio stations, both... more
*
Bell ExpressVu LP
North York, Ontario, Canada
Launched in September 1997, Bell ExpressVu is the largest and fastest growing direct-to-home (DTH) television company in Canada and the fifth largest broadcast distributor in the country with over 725,000 subscribers as of December 2000. Currently, the company offers more than 200 video... more
*
SES ASTRA
Austin, Texas
SES ASTRA operates the ASTRA Satellite System, offering a comprehensive portfolio of broadcast and broadband solutions for customers in Europe and beyond. ASTRA broadcasts television and radio programmes directly to millions of homes, and provides internet access and network services to... more
*
SES GLOBAL company
SES GLOBAL (Euronext Paris, Luxembourg Stock Exchange: SESG) wholly owns three market-leading satellite operators, SES ASTRA in Europe, SES AMERICOM in North America, and SES NEW SKIES, which provide global coverage and connectivity. The Company also holds strategic participations in... more
*
Sentech
Carrollton, Texas
Sentech has been at the leading edge of communication technology, pioneering the provisioning of broadcast signal distribution services. Sentech, a commercially operated, state-owned enterprise, is the largest signal distributor for broadcasting in Africa, transmitting programs for... more
*
Shaw Communications Inc
Calgary, Alberta, Canada
Shaw Communications Inc. is a communications company whose core business is providing broadband cable television, Internet, Digital Phone, telecommunications services (through Shaw Business Solutions) and satellite direct-to-home services (through Star Choice) to approximately 3.3 million... more
*
Arabsat
Backed by the 21 member countries of the Arab League, and with its 30-year heritage of continuous operations, Arabsat offers the Arab world an unrivalled range of satellite-based communications services such as Direct-to-Home Television and Radio, telephony, Internet and direct Broadband... more
*
MEASAT
*
Tata Sky Ltd.
Tata Sky Ltd., a joint venture of TATA and STAR, is committed to build a state-of-the-art Digital infrastructure for Pay Television in India. Tata Sky plans to introduce a nationwide Direct-to-Home (DTH) service that would allow it to reach every Indian home, however remote it may be. The... more
*
AlphaStar International Inc
Greenwich, Connecticut
AlphaStar is a 21st Century globally integrated Communications Company offering continuous full-motion high definition video, in IP multicasting and streaming formats, television and other multimedia programming services to the Internet through its uniquely positioned, high-bandwidth... more
*
Astro
Astro is Malaysia's leading multimedia broadcaster and producer of Malay, Chinese, Indian and English language programming content. It owns and operates the only direct-to-home satellite TV service with access to some 10 million viewers in over 2 million homes, representing 38% of TV... more
*
Pittsburgh International Telecommunications Inc
Pittsburgh, Pennsylvania
Pittsburgh International Telecommunications was established in 1983 as Mobile Satellite Communications, Inc. in Pittsburgh, Pennsylvania. The company provided mobile satellite uplinking services and owned and operated one C-Band transportable vehicle, which serviced the major television... more
*
ProtoStar LTD
San Francisco, California
ProtoStar is an Asian satellite services operator that was formed to acquire, launch and operate high-power geostationary satellites to lease capacity to Asian DTH and broadband service providers. The technical characteristics of its satellites and the configuration of the satellite... more
*
ASC Enterprises Limited
Lexington, Kentucky
*
Super Value Channel Inc
Pomona, California
SVC sells a variety of consumer products through DTH satellite TV, Cable TV, and over the internet. With full-scale TV production facility and multi-lingual "TV Shopping Experts" who may speak the ethnic languages to better service the customers, SVC is capable to broadcasting informative... more
*
SET Discovery Ltd.
SET Discovery Private Limited is a joint venture between SET India Pvt. Ltd. and Discovery Communications India. The company was set up in April 2002. Today, the company distributes 15 leading channels under the brand name of TheOneAlliance to over 61 million homes spread over 4000 cities... more
*
Atlanta DTH , Inc.
City Of Industry, California
Established in 1993, Atlanta DTH, Inc. is a leading supplier in the DTH satellite industry. We provide a complete product line of DTH satellite equipment such as IRD and LNBF, as well as customer-driven satellite network services and customer management system. ADTH's RV division... more
*
Cyfrowy Polsat S.A.
Launched in 1999, Cyfrowy Polsat offers today 35 television channels in the Polish language and five radio channels as well as hundreds of international Free-To-Air channels. The platform also offers interactive applications, such as TV banking, weather forecasts, SMS Chat, e-mail and... more
Posted by ramkumar at 9:26 AM 0 comments
Advanced Search
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You searched for:
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Refine by:
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Advanced Search
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Digital Dth
Dth Bit
Dth Bit Manufacturing
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Dth Drill
Dth Hammer
Dth Hammer Manufacturing
Dth Operator
Dth Platform
Dth Platform Operator
Dth Satellite
Dth Satellite Space
Dth Satellite Television
Dth Service Provider
Tv Dth
Expand By:
Cable Programming
Digital Satellite
Digital Satellite Television
Direct Broadcast Satellite
DIRECTV Programming
Local Cable
Main Cable
Pay TV
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Satellite TV
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Sort By: Relevance (Default) Company Name Ascending Company Name Descending Revenue Results 1-24 of 24 companies
DIRECTV Inc
El Segundo, California
The DIRECTV Group, Inc. is a provider of digital television entertainment in the United States and Latin America. The business segments, DIRECTV U.S. and DIRECTV Latin America are engaged in acquiring, promoting, selling and/or distributing digital entertainment programming through... more
DISH Network Corporation
Englewood, Colorado
DISH Network Corporation is a provider of satellite delivered digital television to customers across the United States. DISH Network services include hundreds of video, audio and data channels, interactive television channels, digital video recording, high definition television,... more
EchoStar Communications Corporation
Inglewood, Colorado
EchoStar Corporation (EchoStar), formerly EchoStar Holding Corporation, will operate two primary businesses: digital set-top box business and a fixed satellite services business. EchoStar had a spin-off from DISH Network on January 1, 2008. The Company’s set-top box business designs,... more
Intelsat , Ltd.
Washington , Dc, District of Columbia
Intelsat Corporation is a provider of fixed satellite services worldwide and a provider of these services to each of the media and network services sectors. The Company provides service on a global fleet of 26 satellites that are integrated with 27 other satellites owned by other... more
GlobeCast
London, United Kingdom
GlobeCast, a subsidiary of France Telecom, is the leading global provider of content management and worldwide transmission services for professional broadcast delivery. The company operates a secure global satellite and fibre network to manage and transport 10 million hours of video... more
Telesat
Gloucester, Ontario, Canada
Telesat is a pioneer and world leader in satellite operations and systems management. The company made history in 1972 with the launch of the first Canadian commercial communications satellite in geostationary orbit. Today, Telesat competes with other top international satellite fleets in... more
Arqiva Limited
Winchester, Hampshire, United Kingdom
Arqiva has a 50-year history in transmission and has helped pioneer the technologies of the digital age. 22 million UK homes receive ITV, Channel 4 and Five via Arqiva's national transmitter networks. The company also provides transmission for most UK independent radio stations, both... more
Bell ExpressVu LP
North York, Ontario, Canada
Launched in September 1997, Bell ExpressVu is the largest and fastest growing direct-to-home (DTH) television company in Canada and the fifth largest broadcast distributor in the country with over 725,000 subscribers as of December 2000. Currently, the company offers more than 200 video... more
SES ASTRA
Austin, Texas
SES ASTRA operates the ASTRA Satellite System, offering a comprehensive portfolio of broadcast and broadband solutions for customers in Europe and beyond. ASTRA broadcasts television and radio programmes directly to millions of homes, and provides internet access and network services to... more
SES GLOBAL company
SES GLOBAL (Euronext Paris, Luxembourg Stock Exchange: SESG) wholly owns three market-leading satellite operators, SES ASTRA in Europe, SES AMERICOM in North America, and SES NEW SKIES, which provide global coverage and connectivity. The Company also holds strategic participations in... more
Sentech
Carrollton, Texas
Sentech has been at the leading edge of communication technology, pioneering the provisioning of broadcast signal distribution services. Sentech, a commercially operated, state-owned enterprise, is the largest signal distributor for broadcasting in Africa, transmitting programs for... more
Shaw Communications Inc
Calgary, Alberta, Canada
Shaw Communications Inc. is a communications company whose core business is providing broadband cable television, Internet, Digital Phone, telecommunications services (through Shaw Business Solutions) and satellite direct-to-home services (through Star Choice) to approximately 3.3 million... more
Arabsat
Backed by the 21 member countries of the Arab League, and with its 30-year heritage of continuous operations, Arabsat offers the Arab world an unrivalled range of satellite-based communications services such as Direct-to-Home Television and Radio, telephony, Internet and direct Broadband... more
MEASAT
Tata Sky Ltd.
Tata Sky Ltd., a joint venture of TATA and STAR, is committed to build a state-of-the-art Digital infrastructure for Pay Television in India. Tata Sky plans to introduce a nationwide Direct-to-Home (DTH) service that would allow it to reach every Indian home, however remote it may be. The... more
AlphaStar International Inc
Greenwich, Connecticut
AlphaStar is a 21st Century globally integrated Communications Company offering continuous full-motion high definition video, in IP multicasting and streaming formats, television and other multimedia programming services to the Internet through its uniquely positioned, high-bandwidth... more
Astro
Astro is Malaysia's leading multimedia broadcaster and producer of Malay, Chinese, Indian and English language programming content. It owns and operates the only direct-to-home satellite TV service with access to some 10 million viewers in over 2 million homes, representing 38% of TV... more
Pittsburgh International Telecommunications Inc
Pittsburgh, Pennsylvania
Pittsburgh International Telecommunications was established in 1983 as Mobile Satellite Communications, Inc. in Pittsburgh, Pennsylvania. The company provided mobile satellite uplinking services and owned and operated one C-Band transportable vehicle, which serviced the major television... more
ProtoStar LTD
San Francisco, California
ProtoStar is an Asian satellite services operator that was formed to acquire, launch and operate high-power geostationary satellites to lease capacity to Asian DTH and broadband service providers. The technical characteristics of its satellites and the configuration of the satellite... more
ASC Enterprises Limited
Lexington, Kentucky
Super Value Channel Inc
Pomona, California
SVC sells a variety of consumer products through DTH satellite TV, Cable TV, and over the internet. With full-scale TV production facility and multi-lingual "TV Shopping Experts" who may speak the ethnic languages to better service the customers, SVC is capable to broadcasting informative... more
SET Discovery Ltd.
SET Discovery Private Limited is a joint venture between SET India Pvt. Ltd. and Discovery Communications India. The company was set up in April 2002. Today, the company distributes 15 leading channels under the brand name of TheOneAlliance to over 61 million homes spread over 4000 cities... more
Atlanta DTH , Inc.
City Of Industry, California
Established in 1993, Atlanta DTH, Inc. is a leading supplier in the DTH satellite industry. We provide a complete product line of DTH satellite equipment such as IRD and LNBF, as well as customer-driven satellite network services and customer management system. ADTH's RV division... more
Cyfrowy Polsat S.A.
Launched in 1999, Cyfrowy Polsat offers today 35 television channels in the Polish language and five radio channels as well as hundreds of international Free-To-Air channels. The platform also offers interactive applications, such as TV banking, weather forecasts, SMS Chat, e-mail and... more
Posted by ramkumar at 9:26 AM 0 comments
This article contains weasel words, vague phrasing that often accompanies biased or unverifiable information. Such statements should be clarified or removed. (March 2009)
Satellite television is television delivered by the means of communications satellite and received by a satellite dish and set-top box. In many areas of the world it provides a wide range of channels and services, often to areas that are not serviced by terrestrial or cable providers.
Contents
[hide]
1 History
2 Technology
3 Standards
4 Categories of usage
4.1 Direct broadcast via satellite
4.2 Television receive-only
4.2.1 Direct to home television
4.2.2 Programming
4.2.3 Broadcasting centers
4.2.4 Encryption and transmission
4.2.5 The dish
4.2.6 The receiver
5 Satellite television by region and country
5.1 United States
5.2 India
5.3 Canada
5.4 United Kingdom
6 See also
7 References
8 External links
[edit] History
The first satellite television signal was relayed from Europe to the Telstar satellite over North America in 1962. The first geosynchronous communication satellite, Syncom 2 was launched in 1963. The world's first commercial communication satellite, called Intelsat I (nicknamed Early Bird), was launched into synchronous orbit on April 6, 1965. The first national network of satellite television, called Orbita, was created in Soviet Union in 1967, and was based on the principle of using the highly elliptical Molniya satellite for re-broadcasting and delivering of TV signal to ground downlink stations. The first domestic North American satellite to carry television was Canada’s geostationary Anik 1, which was launched in 1972.[1] ATS-6, the world's first experimental educational and Direct Broadcast Satellite, was launched in 1974. The first Soviet geostationary satellite to carry Direct-To-Home television, called Ekran, was launched in 1976.
[edit] Technology
Satellites used for television signals are generally in either naturally highly elliptical (with inclination of +/-63.4 degrees and orbital period of about 12 hours, also known as Molniya orbit) or geostationary orbit 37,000 km (22,300 miles) above the earth’s equator.
Satellite television, like other communications relayed by satellite, starts with a transmitting antenna located at an uplink facility. Uplink satellite dishes are very large, as much as 9 to 12 meters (30 to 40 feet) in diameter. The increased diameter results in more accurate aiming and increased signal strength at the satellite. The uplink dish is pointed toward a specific satellite and the uplinked signals are transmitted within a specific frequency range, so as to be received by one of the transponders tuned to that frequency range aboard that satellite. The transponder 'retransmits' the signals back to Earth but at a different frequency band (a process known as translation, used to avoid interference with the uplink signal), typically in the C-band (4–8 GHz) or Ku-band (12–18 GHz) or both. The leg of the signal path from the satellite to the receiving Earth station is called the downlink.
A typical satellite has up to 32 transponders for Ku-band and up to 24 for a C-band only satellite, or more for hybrid satellites. Typical transponders each have a bandwidth between 27 MHz and 50 MHz. Each geo-stationary C-band satellite needs to be spaced 2 degrees from the next satellite (to avoid interference). For Ku the spacing can be 1 degree. This means that there is an upper limit of 360/2 = 180 geostationary C-band satellites and 360/1 = 360 geostationary Ku-band satellites. C-band transmission is susceptible to terrestrial interference while Ku-band transmission is affected by rain (as water is an excellent absorber of microwaves at this particular frequency).
The downlinked satellite signal, quite weak after traveling the great distance (see inverse-square law), is collected by a parabolic receiving dish, which reflects the weak signal to the dish’s focal point. Mounted on brackets at the dish's focal point is a device called a feedhorn. This feedhorn is essentially the flared front-end of a section of waveguide that gathers the signals at or near the focal point and 'conducts' them to a probe or pickup connected to a low-noise block downconverter or LNB. The LNB amplifies the relatively weak signals, filters the block of frequencies in which the satellite TV signals are transmitted, and converts the block of frequencies to a lower frequency range in the L-band range. The evolution of LNBs was one of necessity and invention.
The original C-Band satellite TV systems used a Low Noise Amplifier connected to the feedhorn at the focal point of the dish. The amplified signal was then fed via very expensive and sometimes 50 ohm impedance gas filled hardline coaxial cable to an indoor receiver or, in other designs, fed to a downconverter (a mixer and a voltage tuned oscillator with some filter circuitry) for downconversion to an intermediate frequency. The channel selection was controlled, typically by a voltage tuned oscillator with the tuning voltage being fed via a separate cable to the headend. But this design evolved.
Designs for microstrip based converters for Amateur Radio frequencies were adapted for the 4 GHz C-Band. Central to these designs was concept of block downconversion of a range of frequencies to a lower, and technologically more easily handled block of frequencies (intermediate frequency).
The advantages of using an LNB are that cheaper cable could be used to connect the indoor receiver with the satellite TV dish and LNB, and that the technology for handling the signal at L-Band and UHF was far cheaper than that for handling the signal at C-Band frequencies. The shift to cheaper technology from the 50 Ohm impedance cable and N-Connectors of the early C-Band systems to the cheaper 75 Ohm technology and F-Connectors allowed the early satellite TV receivers to use, what were in reality, modified UHF TV tuners which selected the satellite television channel for down conversion to another lower intermediate frequency centered on 70 MHz where it was demodulated. This shift allowed the satellite television DTH industry to change from being a largely hobbyist one where receivers were built in low numbers and complete systems were expensive (costing thousands of Dollars) to a far more commercial one of mass production.
Direct broadcast satellite dishes are fitted with an LNBF, which integrates the feedhorn with the LNB.
The satellite receiver demodulates and converts the signals to the desired form (outputs for television, audio, data, etc.). Sometimes, the receiver includes the capability to unscramble or decrypt; the receiver is then called an Integrated receiver/decoder or IRD. The cable connecting the receiver to the LNBF or LNB must be of the low loss type RG-6, quad shield RG-6 or RG-11, etc. It cannot be standard RG-59.
[edit] Standards
Analog television distributed via satellite is usually sent scrambled or unscrambled in NTSC, PAL, or SECAM television broadcast standards. The analog signal is frequency modulated and is converted from an FM signal to what is referred to as baseband. This baseband comprises the video signal and the audio subcarrier(s). The audio subcarrier is further demodulated to provide a raw audio signal.
If the signal is a digitized television signal or multiplex of signals, it is typically QPSK.
In general, digital television, including that transmitted via satellites, are generally based on open standards such as MPEG and DVB-S.
The conditional access encryption/scrambling methods include BISS, Conax, Digicipher, Irdeto, Nagravision, PowerVu, Viaccess, Videocipher, and VideoGuard. Many conditional access systems have been compromised.
[edit] Categories of usage
There are three primary types of satellite television usage: reception direct by the viewer, reception by local television affiliates, or reception by headends for distribution across terrestrial cable systems.
Direct to the viewer reception includes direct broadcast satellite or DBS and television receive-only or TVRO, both used for homes and businesses including hotels, etc.
[edit] Direct broadcast via satellite
Direct broadcast satellite, (DBS) also known as "Direct-To-Home" is a relatively recent development in the world of television distribution. “Direct broadcast satellite” can either refer to the communications satellites themselves that deliver DBS service or the actual television service. DBS systems are commonly referred to as "mini-dish" systems. DBS uses the upper portion of the Ku band, as well as portions of the Ka band.
Modified DBS systems can also run on C-band satellites and have been used by some networks in the past to get around legislation by some countries against reception of Ku-band transmissions.
Most of the DBS systems use the DVB-S standard for transmission. With Pay-TV services, the datastream is encrypted and requires proprietary reception equipment. While the underlying reception technology is similar, the Pay-TV technology is proprietary, often consisting of a Conditional Access Module and smart card.
This measure assures satellite television providers that only authorised, paying subscribers have access to Pay TV content but at the same time can allow free-to-air (FTA) channels to be viewed even by the people with standard equipment (DBS receivers without the Conditional Access Modules) available in the market.
[edit] Television receive-only
The term Television receive-only, or TVRO, arose during the early days of satellite television reception to differentiate it from commercial satellite television uplink and downlink operations (transmit and receive). This was before there was a DTH satellite television broadcast industry. Satellite television channels at that time were intended to be used by cable television networks rather than received by home viewers. Satellite TV receiver systems were largely constructed by hobbyists and engineers. These TVRO system operated mainly on the C band frequencies and the dishes required were large; typically over 3 meters (10 ft) in diameter. Consequently TVRO is often referred to as "big dish" or "Big Ugly Dish" (BUD) satellite television.
TVRO systems are designed to receive analog and digital satellite feeds of both television or audio from both C-band and Ku-band transponders on FSS-type satellites. The higher frequency Ku-band systems tend to be Direct To Home systems and can use a smaller dish antenna because of the higher power transmissions and greater antenna gain.
TVRO systems tend to use larger rather than smaller satellite dish antennas, since it is more likely that the owner of a TVRO system would have a C-band-only setup rather than a Ku band-only setup. Additional receiver boxes allow for different types of digital satellite signal reception, such as DVB/MPEG-2 and 4DTV.
The narrow beam width of a normal parabolic satellite antenna means it can only receive signals from a single satellite at a time. Simulsat or the Vertex-RSI TORUS, is a quasi-parabolic satellite earthstation antenna that is capable of receiving satellite transmissions from 35 or more C- and Ku-band satellites simultaneously.
[edit] Direct to home television
Today, most satellite TV customers in developed television markets get their programming through a direct broadcast satellite (DBS) provider, such as DISH TV or DTH platform. The provider selects programs and broadcasts them to subscribers as a set package. Basically, the provider’s goal is to bring dozens or even hundreds of channels to the customers television in a form that approximates the competition from Cable TV. Unlike earlier programming, the provider’s broadcast is completely digital, which means it has high picture and stereo sound quality. Early satellite television was broadcast in C-band - radio in the 3.4-gigahertz (GHz) to 7 GHz frequency range. Digital broadcast satellite transmits programming in the Ku frequency range (10 GHz to 14 GHz ). There are five major components involved in a direct to home (DTH) satellite system: the programming source, the broadcast center, the satellite, the satellite dish and the receiver.
Programming sources are simply the channels that provide programming for broadcast. The provider (the DTH platform) doesn’t create original programming itself; it pays other companies (HBO, for example, or ESPN or STAR TV or Sahara etc.) for the right to broadcast their content via satellite. In this way, the provider is kind of like a broker between the viewer and the actual programming sources. (Cable television networks also work on the same principle.) The broadcast center is the central hub of the system. At the broadcast center or the Playout & Uplink location, the television provider receives signals from various programming sources, compresses these signals using digital compression (scrambling if necessary), and beams a broadcast signal to the proper satellite. The satellite receive the signal from the broadcast station and rebroadcast them to the ground. The viewer’s dish picks up the signal from the satellite (or multiple satellites in the same part of the sky) and passes it on to the receiver in the viewer’s house. The receiver processes the signal and passes it on to a standard television. These are the steps in greater detail:
[edit] Programming
Satellite TV providers get programming from two major sources: International turnaround channels (such as HBO, ESPN and CNN, STAR TV, SET, B4U etc) and various local channels (SaBe TV, Sahara TV, Doordarshan, etc). Most of the turnaround channels also provide programming for cable television, so sometimes some of the DTH platforms will add in some special channels exclusive to itself to attract more subscriptions. Turnaround channels usually have a distribution center that beams their programming to a geostationary satellite. The broadcast center uses large satellite dishes to pick up these analog and digital signals from several sources.
[edit] Broadcasting centers
The broadcast center converts all of this programming into a high-quality, uncompressed digital stream. At this point, the stream contains a vast quantity of data — about 270 megabits per second (Mbit/s) for each channel. In order to transmit the signal from there, the broadcast center has to compress it. Otherwise, it would be too big for the satellite to handle. The providers use the MPEG-2 compressed video format — the same format used to store movies on DVDs. With MPEG-2 compression, the provider can reduce the 270-Mbit/s stream to about 3 or 10 Mbit/s (depending on the type of programming). This is the crucial step that has made DTH service a success. With digital compression, a typical satellite can transmit about 200 channels. Without digital compression, it can transmit about 30 channels. At the broadcast center, the high-quality digital stream of video goes through an MPEG-2 encoder, which converts the programming to MPEG-2 video of the correct size and format for the satellite receiver in your house.
[edit] Encryption and transmission
After the video is compressed, the provider needs to encrypt it in order to keep people from accessing it for free. Encryption scrambles the digital data in such a way that it can only be decrypted (converted back into usable data) if the receiver has the correct decoding satellite receiver with decryption algorithm and security keys. Once the signal is compressed and encrypted, the broadcast center beams it directly to one of its satellites. The satellite picks up the signal, amplifies it and beams it back to Earth, where viewers can pick it up.
[edit] The dish
A satellite dish is just a special kind of antenna designed to focus on a specific broadcast source. The standard dish consists of a parabolic (bowl-shaped) surface and a central feed horn. To transmit a signal, a controller sends it through the horn, and the dish focuses the signal into a relatively narrow beam. The dish on the receiving end can’t transmit information; it can only receive it. The receiving dish works in the exact opposite way of the transmitter. When a beam hits the curved dish, the parabola shape reflects the radio signal inward onto a particular point, just like a concave mirror focuses light onto a particular point. The curved dish focuses incoming radio waves onto the feed horn. In this case, the point is the dish’s feed horn, which passes the signal onto the receiving equipment. In an ideal setup, there aren’t any major obstacles between the satellite and the dish, so the dish receives a clear signal. In some systems, the dish needs to pick up signals from two or more satellites at the same time. The satellites may be close enough together that a regular dish with a single horn can pick up signals from both. This compromises quality somewhat, because the dish isn’t aimed directly at one or more of the satellites. A new dish design uses two or more horns to pick up different satellite signals. As the beams from different satellites hit the curved dish, they reflect at different angles so that one beam hits one of the horns and another beam hits a different horn. The central element in the feed horn is the low noise blockdown converter, or LNB. The LNB amplifies the signal bouncing off the dish and filters out the noise (signals not carrying programming). The LNB passes the amplified, filtered signal to the satellite receiver inside the viewer’s house.
[edit] The receiver
Further information: Set-top box
The end component in the entire satellite TV system is the receiver. The receiver has four essential jobs: It de-scrambles the encrypted signal. In order to unlock the signal, the receiver needs the proper decoder chip for that programming package. The provider can communicate with the chip, via the satellite signal, to make necessary adjustments to its decoding programs. The provider may occasionally send signals that disrupt illegal de-scramblers, as an electronic counter measure (ECM) against illegal users. It takes the digital MPEG-2 signal and converts it into an analog format that a standard television can recognize. Since the receiver spits out only one channel at a time, you can’t tape one program and watch another. You also can’t watch two different programs on two TVs hooked up to the same receiver. In order to do these things, which are standard on conventional cable, you need to buy an additional receiver. Some receivers have a number of other features as well. They pick up a programming schedule signal from the provider and present this information in an onscreen programming guide. Many receivers have parental lock-out options, and some have built-in Digital Video Recorders (DVRs), which let you pause live television or record it on a hard drive. While digital broadcast satellite service is still lacking some of the basic features of conventional cable (the ability to easily split signals between different TVs and VCRs, for example), its high-quality picture, varied programming selection and extended service areas are features now seen as an alternative. With the rise of digital cable, which also has improved picture quality and extended channel selection, the TV war is really heating up. Just about anything could happen in the next 10 years as all of these television providers battle it out.
[edit] Satellite television by region and country
This article contains weasel words, vague phrasing that often accompanies biased or unverifiable information. Such statements should be clarified or removed. (March 2009)
[edit] United States
It has been suggested that this section be split into a new article entitled Satellite television in the United States. (Discuss)
Currently, there are two primary satellite television providers of subscription based service available to United States consumers: Dish Network and DirecTV.
Over the past three decades, various U.S. satellite services have come and gone or combined to form the current primary services. In 1975 RCA created Satcom 1, the first satellite built especially for use by the then three national television networks (CBS, NBC, and ABC). Later that same year, HBO leased a transponder on Satcom 1 and began transmission of television programs via satellite to cable systems. Owners of cable systems paid $10,000 to install 3-meter dishes to receive TV signal in C-band. In 1976 Taylor Howard built an amateur system, which consisted of a converted military surplus radar dish and a satellite receiver designed and built by Howard, for home satellite reception. Taylor's system could be used for receiving TV programs both from American and Soviet communication satellites. In 1977 Pat Robertson launched the first satellite-delivered basic cable service called the CBN Cable Network. In 1979, the Satellite Home Viewers Act allowed homeowners in the US to own and operate their own home satellite system, consisting of C-band equipment from a multitude of manufacturers who were making parts for systems such as Taylor Howard's, and began a large controversy of which channels could be received by whom.
USSB was a direct-to-home service founded in 1981. In the early 1990s they partnered with Hughes and continued operation until purchased in 1998 by DirecTV.
In 1991 Primestar launched as the first North American DBS service. Hughes’s DirecTV, the first national high-powered upper Ku-band DBS system, went online in 1994. The DirecTV system became the new delivery vehicle for USSB. News Corporation currently holds a 38% stake, which it is in the process of selling to Liberty Media. In 1996, EchoStar’s Dish Network went online in the United States and has gone on to similar success as DirecTV’s primary competitor. The AlphaStar service launched in 1996 and went into bankruptcy in 1997. Dominion Video Satellite Inc's Sky Angel also went online in the United States in 1996 with its DBS service geared towards "faith and family". Primestar sold its assets to Hughes in 1999 and switched from DBS to an IPTV platform.
In 2004, Cablevision’s Voom service went online, specifically catering to the emerging market of HDTV owners and aficionados, but folded in April 2005. The service’s “exclusive” high-definition channels were migrated to the Dish Network system. Commercial DBS services are the primary competition to cable television service, although the two types of service have significantly different regulatory requirements (for example, cable television has public access requirements, and the two types of distribution have different regulations regarding carriage of local stations).
90cm multiple-LNA toroidal satellite dish
The majority of ethnic-language broadcasts in North America are carried on Ku band free-to-air. The largest concentration of ethnic programming is on Galaxy 25 at 97° W. Pittsburgh International Telecommunications and GlobeCast World TV offers a mix of free and pay-TV ethnic channels in the internationally-standard DVB-S format, as do others. Home2US Communications Inc. also offers several ethnic channels on AMC-4 at 101° W, as well as other free and pay-TV channels. Several U.S.-English language network affiliates (representing CBS, NBC, ABC, PBS, FOX, the CW (formerly the WB and UPN), ION Network and MyNetworkTV) are available as free-to-air broadcasts, as are the three U.S.-Spanish language networks (Univisión, Telefutura and Telemundo). The number of free-to-air specialty channels is otherwise rather limited. Specific FTA offerings tend to appear and disappear rather often and typically with little or no notice, although sites such as LyngSat do track the changing availability of both free and pay channels worldwide.[2]
[edit] India
The Indian Subcontinent have many service providers. They are Big TV(ADAG Group), Dish TV, Tata Sky(Tata and Sky), Sun DTH(Sun Group), DD Direct Plus(Prasar Bharathi), Airtel DTH(Bharathi) are some of them. Big TV, Sun DTH, Airtel DTH uses MPEG-4 technology for transmission the other providers use older technologies. DD Direct Plus offers free services while all other providers are subscription based.
[edit] Canada
Currently, there are two primary satellite television providers of subscription based service available to Canadians consumers: Bell TV and Shaw Direct.
[edit] United Kingdom
The leading satellite television broadcaster in the UK is a subscription based service named Sky Digital, marketed by British Sky Broadcasting. Since May 2008, a subscription free alternative known as Freesat has been available as part of preparations to migrate the UK to exclusively digital TV broadcasting. The Freesat service is run jointly by the UK's two largest broadcasters, ITV and BBC and should not be confused with the similarly named freesat from sky, a subscription free version of the Sky platform.
[edit] See also
Satellite dish
Microwave antenna
Commercialization of space
FTA Receiver
Molniya orbit
[edit] References
^ Robertson, Lloyd (1972-11-09). "Anik A1 launching: bridging the gap". CBC English TV. http://archives.cbc.ca/500f.asp?id=1-75-92-594. Retrieved 2007-01-25.
^ LyngSat tracking
[edit] External links
Lyngemark Satellite Charts
Worldwide satellite locations and feed information, available in a wide variety of languages
Upcoming Satellites
SES Astra interactive fleet map
SES Astra channel guide
Satellite-TV/TVRO/ C-Band FAQ List
Linowsat PID-Lists and Videobitrate Charts
Satellite and Digital Broadcasting
Steve Birkill's History of C-Band and Early Satellite TV
Mark Long's Russian Statsionar Satellite Systems
Online Satellite Calculations
Online Satellite Finder Based on Google Maps
[show] v • d • eCable, satellite and other specialty television providers
Cable television Asianet Cable Vision · Adams Cable · Adelphia · Airtel Digital Tv · Armstrong Telephone Company · Atlantic Broadband · Austar · Bright House Networks · Buckeye CableSystem · Cablelink · CableOne · Cable TV Hong Kong · Cable TV Wakasa Obama (Japan) · Cablevision (U.S.) · Cablevision (Canada) · Canal Digital · Champion Broadband · Charter · Cogeco · Columbus Communications · Comcast · Com Hem · Cox · DartyBox · EastLink · EMBARQ · ER-Telecom (Russia) · Fastweb (Italy) · First Media · Foxtel · GCI · Global Destiny · Globosat · GUdTV (Guam) · Hathway · Hot · IndosatM2 · Insight · Kabel Deutschland · Knology · Kujtesa · MASTV · MC Cable · MCV Broadband · Mediacom · MetroCast Cablevision · Midcontinent Communications · Millennium Digital Media · Neighbourhood Cable · Net Brasil · Ono · Optus · Persona · Qwest Choice TV · RCS&RDS · RCN · Rogers · Satview Broadband Ltd · Service Electric · SkyCable · Shaw · Smallworld · StarHub TV · Suddenlink · TDC · Tele2 · Tele Columbus (Germany) · Telenet (Belgium) · TelkomVision · TelstraClear InHomeTV · Time Warner · TransACT · TrueVisions · Turksat Kablo · TV Cabo · TVTEL · UCS · UPC Ireland · UPC Netherlands · UPC Romania · Uralsvyazinform (Russia) · Vidéotron · Virgin Media · WOW! · WightCable · Ziggo ·
Satellite television AB Sat · Airtel Digital Tv · AlphaStar · Arab Digital Distribution · ART · Astro · Astro Nusantara · Austar · Bell TV · BIG TV · Boom TV · CanalDigitaal · Canal Digital · CanalSat · CanalSat Calédonie · CanalSat Caraïbes · CanalSat Horizon · CanalSat Reunion · CaspioNet · Cyfra+ · D-smart · DD Direct Plus · DialogTV · Digi TV · Digit-Alb · Digital+ · Digiturk · DirecTV · Dish Network · Dish TV · Dolce · Dream · DStv · Euro1080 · Focus Sat · Foxtel · freesat · Freesat from Sky · Freeview (NZ) · GlobeCast World TV · Globosat · Glorystar · HiTV · Home2US · Indovision · Kristal-Astro · Max TV · MBC (Middle East) · N (Poland) · NOVA Cyprus · NOVA Greece · NTV Plus · Sky Deutschland · Orbit Showtime · PrimeStar · SelecTV · Shaw Direct · Sky Digital · SKY Italia · Sky Latin America · SkyLife · Sky PerfecTV! · SKY TV (NZ) · STAR Select · STAR TV · Sun TV · Tata Sky · Tivù Sat · TPS · TelkomVision · TrueVisions · TV Cabo · TV Vlaanderen Digitaal · TVTEL · UBI World TV · USSB · Viasat · Viasat Ukraine · Voom · WOWOW · Yes
IPTV Aliant TV · Alice Home TV (Italy) · Beeline (Russia) · Belgacom · BSNL · BT Vision · Canal Digital · Clix · Crnogorski Telekom · DartyBox · Deutsche Telekom (T-Home) · Elioni DTV (Estonia) · Fastweb (Italy) · Fine TV · Free · Freewire TV · hanaTV (Korea) · Imagenio · iNES · Infostrada TV (Italy) · KPN · La Télé des P&T (Luxembourg) · Maroc Telecom TV (Morocco) · mio TV · MTNL · Neuf · now TV · Orange · Portugal Telecom (Meo) · Sky Angel · T-com Hrvatska · T-Home Macedonia · TELE2 · Telefónica · TeliaSonera · Telus TV · Tiscali TV (Italy) · Tiscali TV (UK) · TPG IPTV · TrueIPTV (Thailand) · TVCatchup · U-verse · VDC · Viasat
Terrestrial television Boxer (Sweden) · Cablevision (Lebanon) · Doordarshan · Freeview (Australia) · Freeview (NZ) · Freeview (UK) · KPN (The Netherlands) · La 7 Cartapiù (Italy) · Mediaset Premium (Italy) · MiTV · Multi-Choice TV (Barbados) · Pakistan Television Corporation · PlusTV (Finland) · RiksTV (Norway) · Sky Picnic · Télévision Numérique Terrestre (France) · Top Up TV · Televisão Digital Terrestre (Portugal)
Fiber-Optic TVTEL · Verizon FiOS · at&t · meo fibra
[show] v • d • eWireless video and data distribution methods
Advanced Wireless Services · Amateur television · Analog television · Digital radio · Digital television · Digital television in Europe · Digital terrestrial television (DTT or DTTV) ·
Digital Video Broadcasting: ( Terrestrial - Satellite - Handheld ) · DVB-MS · Ku band · Local Multipoint Distribution Service (LMDS) · Microwave · Mobile TV · Multichannel Multipoint Distribution Service (MMDS) now known as Business Radio Service (BRS) · Instructional Television Fixed Service (ITFS) now known as Educational Broadband Service (EBS) · MVDS · MVDDS · Satellite Internet access · Satellite radio · Satellite television · Wi-Fi · WiMAX · Wireless local loop
Retrieved from "http://en.wikipedia.org/wiki/Satellite_television"
Categories: Satellite television | Broadcasting | Satellite ground stations
Hidden categories: Articles with weasel words from March 2009 | Article sections to be split from April 2009 | Articles to be split from April 2009 | All articles to be split
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Posted by ramkumar at 9:23 AM 0 comments
http://pib.nic.in/focus/foyr2001/fomar2001/dth_glines.pdf
Posted by ramkumar at 9:18 AM 0 comments
TV Broadcast URI Schemes
Requirements
W3C Note 21 October 1999
This version:
http://www.w3.org/TR/1999/NOTE-TVWeb-URI-Requirements-19991021
Latest version:
http://www.w3.org/TR/TVWeb-URI-Requirements
Previous version:
http://www.w3.org/TR/1999/NOTE-TVWeb-URI-Requirements-19991019
Editors:
Warner ten Kate (warner.ten.kate@philips.com)
Gomar Thomas (gomer@lgerca.com)
Craig Finseth (craig@finseth.com)
Copyright © 1999 W3C (MIT, INRIA, Keio), All Rights Reserved. W3C liability, trademark, document use and software licensing rules apply.
--------------------------------------------------------------------------------
Status of this document
This Note was produced by the W3C TV-Web Interest Group. It is the result of discussions on URI schemes suited for use in TV Broadcast environments. The document reflects preliminary results, and is intended to serve as a base to further work to design TV Broadcast URIs. Please send comments to the TV-Web mailing list www-tv@w3.org.
This version is an update of the version dated 19 October 1999, fixing a wrong link.
Publication of a W3C Note does not imply endorsement by the entire W3C Membership. A list of current W3C technical reports and publications, including Working Drafts and Notes, can be found at http://www.w3.org/TR.
This section represents the status of this document at the time this version was published. It will become outdated if and when a new version is published.
Table of Contents
Abstract
1. TV Broadcast: Definition and scope
2. Application Scenarios
3. Requirements on Global TV Broadcast URI schemes
4. Exceptions in TV Broadcast URIs
References
Abstract
This document is an informational document and discusses the requirements posed to URI schemes for identifying resources in Television (TV) Broadcast environments. The document is the outcome of discussions on this subject by the W3C TV-Web Interest Group [TVWebIG, TVWebMail].
Typical use cases are summarized where TV Broadcast URIs are involved. A distinction is made between Global and Local usage. Also, a hierarchy of resource types is identified. Requirements related to the Global usage case are listed.
1. TV Broadcast: Definition and scope
Definition of TV Broadcast
In this document TV Broadcast is used as the generic term to refer to currently existing TV systems, their transport protocols, and their typical operation of content provision and distribution. TV Broadcast concerns both digital and analog systems and includes systems like DVB, ATSC, DSS, NTSC, and PAL. The TV Broadcast "network layer" is typically non-IP based.
The term TV Broadcast URI refers to URIs which identify, and possibly locate, TV Broadcast content. In this document "URI" is used to indicate TV Broadcast URI.
Typically, TV Broadcast systems are push systems. The content streamed along a TV Broadcast transport is scheduled by the service provider; the user has no influence on that. In this model the user accesses the stream(s) rather than the server at the upstream station.
Hierarchy in TV Broadcast content
TV Broadcast content is modeled in a four-layer hierachy, consisting of service, event, component, and fragment. Service is at the top, fragment is at the bottom of the hierarchy.
The term service is used to refer to a concatenation of programs, all being broadcast by the same service provider. The programs of a service share some tuning characteristics. Service corresponds to the naming "channel" as used in today's analog TV.
The term event is used to refer to a single TV program. An event consumes a time period within a service and therefore can be characterized with begin and end times. The service provider determines the granularity in which the service is split in events. An event can be a complete program or an episode of a program. Events can be grouped in series, e.g., to form a serial. Events are the typical entities which EPGs list to present program schedule information.
The term component is used to refer the constituents of an event. The audio and video of a TV program are obvious examples. In case of multilingual programs there are multiple audio components. In case of interactive programs the components are the application documents and the other data these applications are using. Next to continuous data like audio and video, component also encompasses discrete data like Web pages and applications describing composition and interactivity. The URI identifying an application can constitute the base URI for the further components referenced by that application.
The term fragment is used to refer to a subpart of a component. For instance, it can be a slice of a video sequence, or a subregion in an image.
Due to the push character of TV Broadcast there are two dimensions of hierarchy, a schedule related and a content related. The first is the hierarchy of transport system, transport stream, service, series, event; The second is the hierarchy of series, event, component, fragment.
The term resource is to be understood as in RFC 2396, sec.1.1 [RFC2396]. In the context of TV Broadcast a resource refers to the entities service, event, component, and fragment in particular.
Setting and usage of TV Broadcast URIs
TV Broadcast applications need a mechanism to identify and locate the components building the application. The URI scheme is a useful tool for that as it opens possibilities for seamless transition in referencing resources at TV Broadcast transport and Internet sites. URI schemes to locate resources at the Internet are well-known, and are not further observed in this document. URI schemes to locate resources in a TV Broadcast transport channel have been proposed, but most are designed with a particular TV Broadcast transport environment in mind.
Next to locating components at TV Broadcast transport channels, another aspect of TV Broadcast URIs concerns referencing the events. In the first place, events are accessible at the TV Broadcast transport channel, possibly at several channels and at multiple periods of time. The above mentioned URI schemes also address this aspect, but all in their own way. In the second place, the content may be stored and made available through another path than the TV Broadcast transport channel. Most evident are local storage, like VCR-type of devices, and the Internet itself. Local storage devices can be connected through an in-home network to the user agent presenting the application. Local storage in the sense of the client's local file system or in the sense of cache buffering are not observed in this document.
TV Broadcast content delivered through a so-called IP-tunnel is considered as content made available through the Internet. An IP-tunnel refers to a forwarding path which is logically separated from the conventional TV Broadcast transport protocol but uses the same physical transmission link.
2. Application Scenarios
Application types, further definition and scope
Applications can be distinguished in usage of URIs for Global and Local scope.
Global refers to URIs contained in documents which can be accessed anywhere around the world, and which identify content related to any TV Broadcast system in the world, including storage devices associated with that TV Broadcast system. Such a global URI may include identification of the TV Broadcast system to be used.
Local refers to URIs contained in documents which are accessed within a certain TV Broadcast system, and which identify content to be accessed through that TV Broadcast system. URIs that reference content outside the local TV Broadcast system, are assumed to be either Global URIs or traditional URIs for locating resources at the Internet.
This document concentrates on Global URIs, as those have a world-wide interest for standardization. It would be nice when Local URIs bear an identical format, but that is considered not a necessary requirement. Local URIs can be specified within their respective application domains. On the other hand, it would be nice when Global URIs can serve as a base URI for Local URIs, either as direct copy or by some mapping function.
Further, URIs can be distinguished in identifying a service or event, and in identifying a particular content item (component or fragment) in such a service or event. This reflects the two dimensions observed above of schedule related and content related hierarchy. The use cases where a content item in a certain service is to be identified while the context isn't already that service, seem rare. Consequently, a URI is not required to carry both informations (service and content item) together.
This distinction suggests that identification of a particular content item belongs to the Local class of URIs, and that Global URIs typically identify a service or an event. However, an exception can be found in the case where the same content item is referenced in various transport contexts, e.g. in a commercial.
An important class of Global URIs identify their resource in a location and time independent way, i.e. independent of the particular TV Broadcast transport system and particular schedule. For instance, they are also valid after local storage. As such, they resemble URN behavior, opposed to URL behavior.
As the set of resources and their various locations can scale to large numbers, it is preferred that the URI scheme imposes a hierarchical structure, certainly when the URI's purpose is to locate a resource. A hierarchy allows for step-by-step resolution and navigation to the resource identified. By that, efficiency and scalability is improved. Further, implying a hierarchical structure allows to group resources, and by that to distinguish between, for example, in identifying a serial and an event in that serial.
Use cases, both Local and Global URI
Below, some representative use cases are listed. An exhaustive list of application scenarios is provided in [USECASES].
Basic EPG type of locating:
Reference TV Broadcast services and events from a Web page for navigating to them. The references are tolerant to modifications in the actual transmission schedule, but a coarse indication can be derived. The broadcast program can be indicated through tuning data or through naming. Next to navigation to the program, the EPG also supports for setting reminders or recording of programs. Instead of a single program, the serial of which the program is part, is referred to, such that setting a reminder or a recording for all episodes can be accomplished. It is the year 2002. Fox is broadcasting a World Cup game from South Korea in both analog and digital formats, with the broadcast reaching North America, Europe, Africa, Asia, Latin America, Australia, etc., through a wide variety of local affiliates and re-broadcast operators. Fox wishes to put a hyperlink to the broadcast on its web site, so that users of Internet-connected TV receivers all over the world with the right software (perhaps native, perhaps downloaded) can click on the hyperlink and have their receivers tune to the broadcast (or set a reminder for the broadcast, if the game is not currently on).
A sports fanatic wants to watch all the above broadcasts by Fox. Therefore he records all the broadcasts and copies the above Fox World Cup page to his local disc. From that page he can access the broadcasts or, when they have been recorded, view them from his recording device. At its site Fox also provides the transmitted broadcasts, albeit at high compression rates. The page will direct users who haven't recorded the broadcast to these videos.
A Web page is composed for presentation on a TV Broadcast receiver. The Web page is delivered in association with a TV Broadcast program (the transmission paths may be physically separated). The Web page includes an object which refers to the associated audio/video image of the TV broadcast program.
In a Web page a TV Broadcast event is referred, but the exact location is not known at authoring time. The URI is incomplete in its information. Instead a query is added to retrieve the missing information. When the available TV Broadcast system supports the query mechanism, the URI can be resolved and the identified resource can be retrieved. The query language is technology-independent, i.e. it is not relying on specific fields, such as SI data, in the TV Broadcast transmission system.
Examples are:
dtv://?program=X-Files dtv://ABC/?lang=sp A TV Broadcast of a soccer match is data-enhanced; in a data carousel module or an encapsulated IP datagram a file is contained which gives up-to-the-second statistics on goals scored, fouls committed, corner kicks taken, shots at goal, shots on goal, etc. The broadcaster wants to put a URI on their web site which references this file, allowing applications on Internet-connected TV receivers all over the world to get to the file and display it in nifty ways.
A data file is transmitted along with a TV program, the data file is containing additional information to that program. It also contains hyperlinks to the programs and/or data in other data files being broadcast on the same channel and in other channels, so that receivers can set reminders for the upcoming game and/or data file.
A Web page is transmitted with a TV Broadcast commercial. The commercial is about an upcoming TV Broadcast program. The viewer can click a hotspot area such as to set a reminder for that program. The Web page can also be accessed at the broadcaster's Web site.
A set of three Web page is transmitted with a TV Broadcast commercial. The viewer can navigate the three pages. The pages are transmitted frequently along various TV Broadcast systems. The pages can also be accessed at the advertiser's Web site, where they are maintained at a particular sub directory. Therefore, the advertiser uses relative referencing between the pages.
A live quiz show is enhanced such that the viewer can play along. The enhancement data are a mixture of Web pages, which compose the quiz's question and answer environment, element values, which carry the actual questions and (correct) answers to be inserted in the Web pages, and procedural cells to control the viewer's score. The Web pages are provided at a Web site long before the show is aired, such that viewers can prepare. The element values are transported along the TV Broadcast transmission channel during the show. They are synchronized with the actions in the show such as to complete and update the application.
There are several levels of play along: some pages provide the viewer with hints such as to ease answering, and some pages provide less alternatives in the multiple choice questions. The viewer can select his level by navigating between these pages.
Upon the actual broadcast an application is broadcast with the program to initiate the enhancement. The application references the Web site, such that upon tuning to the TV Broadcast the Web site's home page gets retrieved. Triggered by stream events in the TV Broadcast transport stream, the application also controls the insertion of element values (questions and answers) and the score management (e.g., no score increment after answer presentation).
A Web site provides a EPG covering programs transmitted world-wide. A viewer is visiting this site and browses the EPG. Upon encountering his favorite movie "Once upon a time in the Cyber" he clicks the item on the EPG. Regretfully, the movie isn't scheduled for the 419 TV Broadcast satellites his receiver is configured to. Instead of setting a reminder, the receiver informs the user the movie will not appear on his reception links.
3. Requirements on Global TV Broadcast URI schemes
Conventions used in this document
In this document three levels of priority are used to indicate the desirability of a requirement.
MUST
The key word "MUST" is to be understood as an essential and critical requirement.
SHOULD
The key word "SHOULD" indicates an important requirement.
MAY
The key word "MAY" indicates a useful feature.
[These key words and their meaning are based upon RFC 2119 [RFC2119]. That RFC specifies similar wording for implementation compliance with a protocol specification. In this document the wording reflects specification compliance with protocol goals.]
Requirements
The URI scheme MUST comply with RFC 2396 [RFC2396].
Where the URI serves as a name identifier (URN), the corresponding URN specifications MUST be taken into account, e.g. [RFC2141, RFC2168].
Where the URI serves as a locator identifier (URL), the definition of the URI scheme MUST follow the guidelines as set forth in [URLGUIDE].
The URI MAY support queries to be posed to the TV Broadcast receiver. The query language MUST be independent to the TV Broadcast system.
The URI scheme SHOULD support relative referencing such that a TV-program with all its associated resources can be referenced against a common base, which is the TV Broadcast URI of that aggregate.
Where the URI serves as a locator identifier (URL), the URI scheme SHOULD include a hierarchical structure either to identify the resoure as a service or an event from a service, or to identify the resource as an event, a component from an event, or a fragment from a component. The structure SHOULD provide optional levels to group events into series or serials and to group components into composites.
Where the URI serves as a name identifier (URN), the URI scheme MAY include such hierarchical structure.
The URI scheme SHOULD support the spectrum of transport protocols applied and standardized in TV Broadcast systems. This includes both audio/video and data broadcast protocols.
A URI MUST be invariant with respect to the normal range of transport stream transformations along the path from provider to user, both in referencing the time and the location of the resource in that transport stream.
Given a URI, it MUST be possible for a receiver to actually locate the resource, or conclude that it is not reachable.
A URI MUST be meaningful when interpreted, independent of the transmission context in which the URI is called. Transmission context refers to a coherent set of content streams as they arrive at the receiver. An example is a set of TV broadcast services sharing a same physical connection; another is an Internet connection. In case the context is the same transmission system as in which the content is located, the URI MUST be resolvable.
Where the URI serves as a name identifier (URN), it SHOULD be resolvable under any of the following network access conditions:
TV Broadcast
Internet
In Home/local storage
The actual resource's retrieved content data MAY differ in terms of content encoding, content quality, performance, and edit version.
Where the URI serves as a name identifier (URN), the scheme MUST support referencing various instantiations of the same content (encoding, quality/compression ratio, versions/edits).
Any actual scheme SHOULD be coordinated with standardisation bodies such as ATSC, DVB, and DAVIC, and SHOULD be reasonably acceptable to those bodies.
The URI scheme MUST interoperate with the Internet access schemes, such as to enable seamless transition in referencing resources at TV Broadcast or Internet sites.
4. Exceptions in TV Broadcast URIs
TV Broadcast differs from the conventional Internet in several ways. The TV Broadcast URI scheme is affected by that in the following aspects:
The host is not necessarily a server identifiable through an IP-address. For instance, the "host" is a transport stream.
The resource access and retrieval scheme is not necessarily IP-stack based.
The resource's availability implicitly depends on, or at least relates to, a transmission schedule.
Because TV Broadcast is a resource constrained environment, it is worthwhile to keep the length of the URI limited. This document does not pose a requirement on a maximum length of a TV Broadcast URI. It is left to the particular application domain to specify such limitations.
References
[RFC2119] Key words for use in RFCs to Indicate Requirement Levels,
RFC 2119, S. Bradner. March 1997.
[TVWebIG] W3C TVWeb Interest Group,
Group page of the W3C TV-Web IG. Philipp Hoschka.
[TVWebMail] TV-Web Mail Archives,
Threads starting with messages 0040, 0041, and 0046. Oct/Nov 1998.
.
[RFC2396] Uniform Resource Identifiers (URI): Generic Syntax,
RFC 2396, T. Berners-Lee, R. Fielding, L. Masinter. Aug. 1998.
[RFC2141] URN Syntax,
RFC 2141, R. Moats. May 1997.
[RFC2168] Resolution of Uniform Resource Identifiers using the Domain Name System,
RFC 2168, R. Daniel, M. Mealling. June 1997.
[URLGUIDE] Guidelines for new URL Schemes,
Internet-Draft, L. Masinter, H.T. Alvestrand, D. Zigmond, R. Petke. March 1999.
[USECASES] Applications list,
Posting to the TV-Web IG, C. Finseth. December 1998.
Posted by ramkumar at 9:13 AM 0 comments
http://www.broadcast-equipment.net
Posted by ramkumar at 9:12 AM 0 comments
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