L64780 LSI Logic Corporation, L64780 Datasheet - Page 68

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

4.4 Parameter Registers
4.4.1 Address Line 0x05
4-16
QAMTYPE
The Parameter registers contain configuration information. If the registers
are read, they indicate the current parameter value. These Parameter
registers are only configurable through the microprocessor.
AFC_CLIPPING
Register Descriptions
0x05
CLIPPING
AFC_
7
Constellation Type
When this register is read, these bits provide the last
value received by the channel, using the TPS signalling
information.
When this register is written to, these bits store the next
Constellation Type value that the system uses. The
values are:
The initial condition for the QAMTYPE is 0b10 ( 64 QAM).
AFC Loop Bandwidth Limiter
This bit selects the combination method between the
Fine Algorithm part and the Coarse Algorithm part.
When using Method I (AFC_CLIPPING = 0), the
combination is done by adding the two values. When the
Coarse part is an integer number of carrier spacing, and
the Fine part is a fraction of the carrier spacing, the result
is the exact frequency offset.
When using Method II (AFC_CLIPPING = 1), the Fine
part is only considered when the AFC Coarse value is 0.
AFC_MODE
QAMTYPE[1:0]
6
00
01
10
11
AFC_FINE
_MODE
5
Definition
QPSK
reserved
16 QAM
64 QAM
AFC_STALL AFC_POL AFC_SENSITIVITY
4
3
2
R/W [1:0]
R/W 7
0