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 front-end devices.

Key Features
• Conforms to EBU specification for DVB-S and DirecTV specification for DSS.
• On-chip digital filtering supports 1 to 45MBaud Symbol rates.
• On-chip 6-bit 60 or 90MHz dual-ADC.
• High speed scanning mode for blind symbol rate/code rate acquisition.
• Automatic IQ phase resolution.
• No signal indicator.
• Up to ±15MHz LNB frequency tracking.
• Fully digital timing and phase recovery loops.
• High level software interface for minimum development time.
• DiSEqC™ v2.2: receive/transmit for full control of LNB and dish.

Applications
• DVB 1 to 45MBaud compliant satellite receivers.
• DSS 20MBaud compliant satellite receivers.
• SCPC receivers. (Single Channel Per Carrier)
• SMATV trans-modulators. (Single Master Antenna TV)
• LMDS (Local Multipoint Distribution Service)
• Satellite PC applications.