| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a head-end system, a receiver, a smart card, and a conditional access system, enabling distribution of multiple variants of a part of a digital signal, such as multiple variants of the audio part or video part of a data stream, without requiring to update receivers. <P>SOLUTION: A digital signal generated by a head-end system enables a receiver to receive and process the digital signal without requiring to identify copies in a second digital signal. Error handling capabilities of the receiver ensure that only one copy is used in the output of the receiver. The error handling capabilities are triggered by making the receiver use one decryption key to descramble all copies. As a result, one copy is descrambled correctly, and the other copies are descrambled incorrectly. <P>COPYRIGHT: (C)2011,JPO&INPIT |
