Patent ID: 7607154

Claim:
A system for the transmission of DVB/MPEG digital signals, particularly for satellite communication, said system comprising: a transmitting station in which a multiplexer ( 32 ) inserts null packets in the DVB/MPEG streams originating from one or more 5 VBR coders or generic data sources ( 31 ) so that their bit-rates are made uniform, and multiplexes them into a single transport stream that is then applied to a modulating chain for transmission over a propagation channel, and a receiving station in which a demodulating chain receives the signal being transmitted over the channel, reconstitutes the transport stream and applies it to a demultiplexer, wherein the modulating chain in the transmitting station comprising: a control circuit ( 72 ) controlling the bit-rate of the MPEG coders or generic data sources ( 31 ); a null-packet eliminator ( 60 ) for removing null packets from the transport stream received from the multiplexer ( 32 ), in order to adapt the bit-rate of the transport stream when the transport stream is transmitted by the transmitting station to the variable channel capacity; an ACM modulator ( 62 ) downstream of the eliminator, which is programmed for coding the stream with the maximum ruggedness allowed by the rate of the incoming useful packets; wherein the receiving station comprises: an ACM demodulator ( 64 ); a null-packet re-inserter ( 66 ) for re-inserting null packets in the transport stream; an evaluator of quality of service ( 68 ) driven by the ACM demodulator ( 64 ) for notifying the level of quality of the received signal to the bit-rate control circuit ( 72 ) of the transmitting station via a return channel; and wherein the bit-rate control circuit ( 72 ) is programmed to change the bit-rate of the VBR coder or coders or generic data sources ( 31 ) depending on the level of quality of service notified by the evaluator ( 68 ), wherein the null-packet eliminator introduces into the transmitted signal indications of the number and position of the eliminated null packets and the null-packet re-inserter uses said indications to restore the null packets.