Abstract: A digital television receiving system having a security mechanism which simultaneously handles two or more separate television program signals is described. The system includes a plurality of digital television receiver mechanisms for receiving a plurality of separate digital television program signal transport streams. The system also includes a multiplexer mechanism coupled to the digital television receiver mechanisms for tagging and multiplexing the received program signal transport streams into a single combined signal transport stream. The combined transport stream is supplied to a security mechanism which limits usable access to the combined stream to authorized users. The system further includes a demultiplexer mechanism for receiving an access-allowed combined transport stream from the security mechanism and demultiplexing the combined transport stream into separate transport streams corresponding to the separate transport streams received by the receiver mechanisms.

Abstract: The invention relates to a method and device for processing multiplexed flow data wherein data is organized in the form of packets provided with an identifier enabling description of the source to which said data contained therein belongs. The inventive method comprises a data filtering step. According to the invention a) a table of correspondence is established, associating each identifier with a processing context, b) the identifier for each incoming packet is recognized, the data thereof is filtered using the filtering parameters of the processing context thereof, the filtered data is stored when a new incoming packet is detected. The invention can be used for digital broadcasting such as digital television, digital radio or to broadcast computer data.

Abstract: A process for automatically measuring the unit of time (ETU=Elementary Time Unit) for communication peripherals dedicated to smart cards during a dialogue between a reader and the smart card, so as to configure the reading device. This process consists in taking account of the descending front of the start bit, taking account of the ascending front of the start bit, and measuring the time between the descending and ascending fronts, which permits the automatic calibration of the communication processor.