Ericsson MX8400, Справочное руководство

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Conditional Access
2/1553-FGC 101 1014 Uen B D-32
Figure D.20 Three Different Scrambling Situations
Scrambling Situation A with shared ECMs. Components 1 and 2 are scrambled with
both ECMs 1 and 2.
Scrambling Situation B without shared ECMs. Component 3 is scrambled with
ECM 3.
Scrambling Situation C with shared ECMs. Components 4 and 5 are scrambled with
ECM 4.
Usually, the operator tries to minimize the number of ECMs in use, as most ECM
generators can generate only a limited number of ECMs and ECM generators are
expensive.
The multiplexer cannot start to scramble a component with a control word before it
has received all the ECMs belonging to the Scrambling Control Group, since the
ECMs must be received by the Decoder within a certain time window. The more
ECMs there are in one Scrambling Control Group. the more time the Multiplexer will
have to spend synchronizing the ECMs.
The multiplexer can handle up to a maximum of 1024 different SCG IDs and a
maximum of eight simulcrypted ECM streams per SCG ID.