- 4DTV
4DTV is the name of the digital TVRO
communications satellite receiver technology manufactured byMotorola for use with large-diameter parabolic dish antennas on the C and Ku frequency bands.History
Since 4DTV technology was originally developed in 1997 by
General Instrument , now the broadband division of Motorola, it predates DVB-based digitaltelevision compression and is incompatible with the DVB standard. The DigiCipher II encryption system replaced the VideoCipher and VideoCipher II systems.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.
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.
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.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.
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.
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.
Technological obsolescence
As DVB technology gradually replaces older, proprietary MPEG transmission systems globally, it is likely that 4DTV will become obsolete. There is no industry-wide timetable in North America for the conversion from 4DTV to DVB. Fact|date=August 2008
External links
* [http://broadband.motorola.com/ Motorola Broadband Division Web site]
* [http://www.coolstf.com/mpeg/ North American MPEG-2 Information]
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