Method for cascading detachable conditional access modules, circuit for inserting a predetermined sequence and circuit for detecting the said sequence in order to implement the method

摘要

The present invention concerns a method for cascading detachable conditional access modules as well as a circuit for inserting a predetermined sequence and a circuit for detecting the sequence. Each module receives a data stream formed of packets of fixed length separated by an interpacket space of fixed length. The interpacket spaces contain a constant predetermined sequence which does not interfere with the packets. The predetermined sequence may be used to regenerate a packet clock signal.