L64704 LSI Logic Corporation, L64704 Datasheet - Page 146

• Manufacturer Part Number: L64704
• Description: Satellite Decoder Technical Manual 5/97
• Manufacturer: LSI Logic Corporation

Figure 7.1
Block Diagram of
Viterbi Decoder Core
Modem Format
7.1.1
Features
7-2
Code Rate
Symbol 0
Symbol 1
ImQ
The Viterbi decoder module has the following features:
The FEC Decoder Pipeline
Depuncture
A Viterbi Decoding Core with a basic rate equal to 1/2
Compliant with European Digital Video Broadcast (DVB) Association
(V4/MOD-B) standards
Depuncturing for code rates equal to 1/2, 2/3, 3/4, 5/6, and 7/8
Accepts input in binary offset or sign magnitude format
Constraint length (K) of seven
Synchronization monitor
Decoded Bit Error Rate (BER) monitor
Maximal Likelihood (ML) decoding algorithm
5.2 dB coding gain for rate equal to 1/2 (no erased input) code at
BER of 1e - 5
Generating Polynomial 171 (Octal) and 133 (Octal)
Module
Rate = 1/2
Decoder
Control
Viterbi
Core
Monitor
Monitor
Sync
BER
Sync Status
Decoded Data
Bit Error Rate