L64780 LSI Logic Corporation, L64780 Datasheet - Page 38

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

3.1.1.1 Serial Output Format
Figure 3.2
CLKOUT54
3-2
SD0[3:0]
DVOUT
Nonhierarchical, Serial Mode, 64 QAM Constellation
SD00 SD01
In serial output mode, the output port of the L64780 is configured as
shown in
Figure 3.1
The output interface passes 4-bit or 3-bit soft decisions to the Viterbi
decoder through the SD0 signal accompanied by the assertion of
DVOUT. All outputs from the output interface are clocked at 54 MHz by
CLKOUT54.
With a 64 QAM constellation, the L64780 extracts six soft decisions from
every constellation point at 9 MHz; for example, one soft decision is
presented every 54 MHz clock cycle. See
Every time a set of soft decisions is received from the bit deinterleaver,
the DVOUT signal stays asserted for six 54 MHz clock cycles. The
DVOUT signal is deasserted only during the scattered pilots, unused
carriers, or guard interval.
Interfaces
* When not used, the signal is deasserted LOW.
L64780
Figure
SD02
Output Interface in Nonhierarchical and Serial Modes
3.1.
SD03 SD04
4
4
SD0
DVOUT
SD1 (not used
DVOUT_LP (not used
CLKOUT54
SD05
SD06
*
)
SD07
Figure
*
)
SD08
3.2.
SD09
SD010