The MT312 is a QPSK/BPSK 1 to 45MBaud demodulator and channel decoder for digital satellite television transmissions to the European Broadcast Union ETS 300 421 specification (ref. 1). It receives analogue I and Q signals from the tuner, digitises and digitally demodulates this signal, and implements the complete DVB/DSS FEC (Forward Error Correction), and de-scrambling function. The output is in the form of MPEG2 or DSS transport stream data packets. An external MPEG clock input is provided for synchronisation to MPEG decoders and DVB Common Interface Modules. The MT312 also provides automatic gain control to the RF frontend devices.