4DTV
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4DTV is the name of the digital TVRO communications satellite receiver technology manufactured by Motorola for use with large-diameter parabolic dish antennas on the C and Ku frequency bands.
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[edit] History
Since 4DTV technology was originally developed in 1997 by General Instrument, now the broadband division of Motorola, it predates DVB-based digital television compression and is incompatible with the DVB standard. The DigiCipher II encryption system replaced the VideoCipher and VideoCipher II systems.
[edit] Usage
In big dish satellite television viewing circles, 4DTV is essentially synonymous with signals that use the DigiCipher 2 standard of signal encryption and compression, also owned by Motorola, although the receivers are also capable of handling analog channels.
DigiCipher 2 was originally intended to be the digital signal compression standard for digital television and audio signals beamed to North America, but cannot be considered a de facto standard, due to the large number of DVB satellite signals available in North America.
About 70% of newer first-generation digital cable networks in North America use the 4DTV/DigiCipher 2 format.
[edit] Channel coding
4DTV digital channels use a "An nnn" format, where "An" is the special two-character satellite abbreviation and "nnn" is an arbitrary three-digit channel number assigned to a specific channel on a particular satellite.
[edit] Decoders
4DTV receivers are also designed to receive any remaining analog TVRO satellite channels and feeds. Three models are available, either new or refurbished:
- DSR-920 (discontinued as of 2003)
- DSR-922
- DSR-905 sidecar, slaved to an analog satellite receiver and only able to receive digital 4DTV channels; requires the use of an additional receiver to be used as a dish mover.
The high cost of these receivers, typically in the US$300-US$700 range, may be a factor that has contributed to rapidly falling subscriber numbers using 4DTV equipment.
[edit] High definition access
The HDD200 receiver interfaces with the 4DTV receiver via the Multi-Media Access Port (MMAP). allowing access to several high definition channels available on the 4DTV system. This unit is no longer in production.
[edit] Programming providers
In the United States, National Programming Service, LLC (NPS) is the primary provider of subscription programming to 4DTV and C band/Ku band users. The second-largest is Satellite Receivers, Ltd. (SRL). NPS is the only programmer that uplinks any content for its subscribers, whereas SRL only makes use of existing channels.
[edit] Advantages
The 4DTV system's main selling point was that it makes use of first-generation master feeds of channels. Therefore, a higher quality signal is achieved, compared other programming options that typically are re-uplinked.
[edit] Technological obsolescence
As DVB technology gradually replaces older, proprietary MPEG transmission systems globally, it is likely that 4DTV will become obsolete by about 2010. There is no industry-wide timetable in North America for the conversion from 4DTV to DVB.
[edit] External links
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