GENERAL DESCRIPTION
This document specifies the MPEG-2 systems demultiplexer IC, SAA7205H, for use in MPEG-2 based digital TV receivers, possibly incorporating conditional access. Such receivers are to be implemented in, for instance, a Digital Video Broadcasting (DVB) set-top box, or Integrated Receiver Decoder (IRD). An example of a demultiplexer/descrambler system configuration, containing a channel decoder module, source decoders, a system microcontroller and a conditional access system is shown in Fig.1.

The main function of the demultiplexer is to separate relevant data from an incoming MPEG-2 systems compliant data stream and pass it to both the individual source decoders and to the system microcontroller. To support descrambling, the demultiplexer interfaces with the descrambler part of a conditional access system (optional). The demultiplexer therefore generates a 9 MHz descrambler chip clock.