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: |
Proprietary Digital Satellite System Standard defined, owned and used by [[DirectTV]]. No public documentation available, here some guessed facts: |
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As [[Modulation Scheme]] DSS uses [[QPSK]]. |
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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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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[[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 |
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. |
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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 [[Demodulator]]s available that can handle both [[DVB-S]] and DSS transmissions, e.g. the [[MT312]]. |
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Revision as of 16:10, 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. 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).
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 MPEG2 Transport Streams.
There are some modern DVB Demodulators available that can handle both DVB-S and DSS transmissions, e.g. the MT312.
Links: