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]]. 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). |
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but what exactly is it? |
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[[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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For Program Service Information a so called "Master Program Guide" (MPG) is used, here all the information is stored that is spread over [[NIT]]s, [[SDT]]s, [[EIT]]s in DVB [[MPEG2 Transport Stream]]s. Thus all [[EPG]] infos can get collected on a single [[PID]]. |
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There are some modern DVB [[Demodulators]] available that can handle both [[DVB-S]] and DSS transmissions, e.g. the [[MT312]]. |
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---- |
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''Links:'' |
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http://www.coolstf.com/mpeg/index.html |
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Revision as of 16:08, 19 September 2004
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. 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).
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.
For Program Service Information a so called "Master Program Guide" (MPG) is used, here all the information is stored that is spread over NITs, SDTs, EITs in DVB MPEG2 Transport Streams. Thus all EPG infos can get collected on a single PID.
There are some modern DVB Demodulators available that can handle both DVB-S and DSS transmissions, e.g. the MT312.
Links: