L64780 LSI Logic Corporation, L64780 Datasheet - Page 39

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

Figure 3.3
CLKOUT54
Figure 3.4
CLKOUT54
3.1.1.2 Parallel Output Format
SD0[3:0]
SD0[3:0]
DVOUT
DVOUT
Nonhierarchical, Serial Mode, 16 QAM Constellation
Nonhierarchical, Serial Mode, QPSK Constellation
SD00
SD00
For a 16 QAM constellation, during which four soft decisions are
extracted every 9 MHz, the DVOUT signal stays asserted over four out
of six 54 MHz clock cycles. See
For the QPSK constellation, only two soft decisions are extracted every
9 MHz, resulting in DVOUT being asserted over two out of six 54 MHz
clock cycles. See
In this mode, soft decisions are output in parallel, and the output
interface of the L64780 is configured. See
Figure 3.5
The output interface passes two soft decisions to the Viterbi decoder in
parallel through SD0 and SD1, accompanied by a data valid indicator.
Output Interface
SD01
SD01
L64780
SD02 SD03
Output Interface in Nonhierarchical and Parallel Modes
Figure
4
4
3.4.
SD0
DVOUT
SD1
DVOUT_LP (not used
CLKOUT54
Figure
* When not used, the signal is deasserted LOW.
SD04
SD02
3.3.
SD05
SD03
Figure
*
)
SD06 SD07
3.5.
3-3