L64780 LSI Logic Corporation, L64780 Datasheet - Page 48

• Manufacturer Part Number: L64780
• Description: Dvb-t Cofdm Demodulator Technical Manual 2/00
• Manufacturer: LSI Logic Corporation

3.2.5 Access to the SDI Block
Figure 3.20 SDI Input Mappings
Figure 3.21 D[23:0] Bus Mapping in Three-Bit Soft Decision
Figure 3.22 D[23:0] Bus Mapping in Four-Bit Soft Decision
3-12
S_P START DV
23
23
26
QSPK I
QSPK I
25
21 20 19
20 19
X
24 23
QPSK Q
QPSK Q
The SDI block performs Symbol Deinterleaving (SDI) as specified in the
ETSI specification. In this mode, the CLKMUXIN signal is configured as
an 18 MHz clock (more precisely, four times the low IF).
The signals on the 24-bit data bus (D) contain up to six soft decisions,
up to four bits per soft decision, a start pulse (START), a data valid (DV)
signal, and the symbol parity (S_P). An odd symbol number is marked
by S_P = 1; even symbol numbers are marked by S_P = 0. These
signals are mapped on the MUXINBUS. See
The data bus (D) is mapped in 3-bit and 4-bit soft decision modes, as
shown in
highest weight position. Note that X means reserved.
Interfaces
17 16 15
16 15
X
Figure 3.21
16 QAM I
16 QAM I
13 12 11
and
12 11
X
Figure
16 QAM Q
16 QAM Q
D[23:0]
3.22, respectively. The MSB is at the
9
X
8
8
7
7
64 QAM I
64 QAM I
Figure
5
3.20.
4
X
4
3
64 QAM Q
3
64 QAM Q
1
X
0
0
0