DSS: Difference between revisions
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Proprietary Digital Satellite System Standard defined, owned and used by [[DirectTV]]. No public documentation available, here some guessed facts: |
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Used by [[DirectTV]]. |
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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. |
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but what exactly is it? |
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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). |
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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. |
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There are some modern DVB Chipsets available that can handle both [[DVB-S]] and DSS transmissions, see the [[Demodulator]] section. |
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== External Links == |
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* http://www.coolstf.com/mpeg/index.html |
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[[Category:Technology]] |
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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.