L64704 LSI Logic Corporation, L64704 Datasheet - Page 149

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

Figure 7.4
Puncture Pattern
for Different Code
Rates
The L64704 receives the encoded data symbols in QPSK or BPSK for-
mat on the RI[5:0] and RQ[5:0] buses. The L64704 receives these sym-
bols in the order shown on the right of L64704 Input Data in
The depuncturing module handles the reordering and the insertion of
erasures into the received symbol stream before the rate equal to 1/2 Vit-
erbi decoder module starts decoding.
Rate 2/3
Rate 3/4
Viterbi Decoder Module
Punctured Symbol (Deleted)
Data (QPSK)
Data (QPSK)
Data (BPSK)
Data (BPSK)
Viterbi Input
Viterbi Input
Viterbi Input
Viterbi Input
Punctured
Punctured
Data
Data
Q
Q
I
I
I
I
Q.1
Q.1
I.1
I.1
Q.1
I.1
I.1
I.1
Q.1
I.1
Q.2
I.2
Q.2
I.2
Q.2
Q.1
Q.1
I.3
Q.2
I.3
Q.3
Q.3
I.3
I.3
Q.3
Q.4
Q.2
Q.2
Q.4
I.4
I.3
I.3
Q.3
Figure
Q.4
7.4.
7-5