4DTV
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4DTV is the name of the digital TVRO communications satellite receiver manufactured by Motorola.
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[edit] History
Since 4DTV technology was originally developed by General Instrument (now the broadband division of Motorola) in 1997, it predates DVB-based digital television compression and therefore is incompatible with the DVB standard.
[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 (which is also owned by Motorola); though the receivers are also capable of handling analog channels.
4DTV was originally intended to be the digital signal compression standard for digital television and audio signals beamed to North America, but cannot truly be considered a de facto standard due to the large amount of available North American DVB satellite signals.
- Approximately 70% of newer first-generation digital cable networks in North America use the 4DTV/DigiCipher 2 format.
[edit] Channel coding
4DTV digital channels use the following format:
G1 100 [where "G1" is the special two-character satellite abbreviation and "100" is the 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. There are three models available either new or second-hand: the DSR-920, the DSR-922, and the DSR-905 sidecar, which is slaved to an analog satellite receiver and can only receive (by itself) digital 4DTV channels.
[edit] Technological obsolescene
Due to DVB technology replacing older high level (propritary) MPEG transmission systems globally -- it can only be assumed that 4DTV will probably become fully obsolete by 2010. There is no industry wide timetable in North America for the conversion from 4DTV to DVB.
ASTC technoligical ambigutites
- ATSC datastreams are a subset of DVB datastreams
- ATSC cannot be carried on 4DTV, except as DATA
- 4DTV conditional access is now considered trailing edge, although it is unclear if any 4DTV transmissions were ever broken.
[edit] External links
Manufacturer related
Technology related
