DSS: Difference between revisions

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As [[Modulation Scheme]] DSS uses [[QPSK]]. [[Viterbi]] and [[Reed-Solomon]] [[Error Correction]] algorithms are the same like defined for DVB. Usually 1/2, 2/3 or 6/7 FEC, a different puncture rate and randomizer are used.
As [[Modulation Scheme]] DSS uses [[QPSK]]. [[Viterbi]] and [[Reed-Solomon]] [[Error Correction]] algorithms are the same like defined for DVB. Usually 1/2, 2/3 or 6/7 FEC, a different puncture rate and randomizer are used.


MPEG2-alike TS Packets are 127 bytes long (instead of 188 Bytes as in MPEG2/DVB -- as far we know 188 bytes packet length have been choosen there for compatibility with ATM networks).
It utilises MPEG-2 like TS Packets that are 127 bytes long (instead of 188 Bytes as used in the case of MPEG-2/DVB -- as far we know 188 bytes packet length have been choosen there for compatibility with ATM networks).


For Program Service Information a so called "Master Program Guide" (MPG) is used, here all the information is stored on a single [[PID]] that is spread over [[NIT]]s, [[SDT]]s, [[EIT]]s in DVB [[MPEG2 Transport Stream]]s.
For Program Service Information a so called "Master Program Guide" (MPG) is used, here all the information is stored on a single [[Packet Identifier|PID]] that is spread over [[Network Information Table|NIT]]s, [[Service Description Table|SDT]]s, [[Event Information Table|EIT]]s in DVB [[MPEG-2 Transport Stream]]s.


There are some modern DVB [[Demodulator]]s available that can handle both [[DVB-S]] and DSS transmissions, e.g. the [[MT312]].
There are some modern DVB Chipsets available that can handle both [[DVB-S]] and DSS transmissions, see the [[Demodulator]] section.


== External Links ==
----
* http://www.coolstf.com/mpeg/index.html
''Links:''


[[Category:Technology]]
http://www.coolstf.com/mpeg/index.html

Latest revision as of 22:18, 6 January 2008

Proprietary Digital Satellite System Standard defined, owned and used by DirectTV. No public documentation available, here some guessed facts:

As Modulation Scheme DSS uses QPSK. Viterbi and Reed-Solomon Error Correction algorithms are the same like defined for DVB. Usually 1/2, 2/3 or 6/7 FEC, a different puncture rate and randomizer are used.

It utilises MPEG-2 like TS Packets that are 127 bytes long (instead of 188 Bytes as used in the case of MPEG-2/DVB -- as far we know 188 bytes packet length have been choosen there for compatibility with ATM networks).

For Program Service Information a so called "Master Program Guide" (MPG) is used, here all the information is stored on a single PID that is spread over NITs, SDTs, EITs in DVB MPEG-2 Transport Streams.

There are some modern DVB Chipsets available that can handle both DVB-S and DSS transmissions, see the Demodulator section.

External Links