MT312 QPSK Demodulator
6 QPSK demodulator
6.1 QPSK Demodulator Read/Write Registers
6.1.1 Symbol Rate. Registers 23 - 24 (R/W)
Def
hex
NAME
ADR
B7
B6
B5
B4
B3
B2
B1
B0
SYM RATE H
SYM RATE L
23
24
SEARCH Reserved
SYM RATE[13:8] in MBaud (high byte)
R/W
R/W
80
80
SYM RAT[7:0] in Mbaud (low byte)
B15:
SEARCH
B14:
B14:
Reserved.
S FMT
Must be set low
Sweep MT312 Format.
If SYM RATE[15:14] = 0 this is the non-search mode, i.e. the known Symbol rate mode.
B13-0:
Required Symbol rate in Mbaud x 256. Unsigned 14 bit number. e.g. for a symbol
rate of 27.5 MBd
SYM RATE = 27.5 * 256 = 7040 = 1B80 (hex)
If any of the two DSS bits are set in the CONFIG register, then the SYM RATE register contents are ignored
and the symbol rate is taken as 20 MBaud. Hence it is not necessary to program the SYM RATE register for
DSS applications.
If SYM RATE[15:14] = 1x this is the Search Mode where x = don't care.
B11-0:
Sub-ranges to be searched (scaled by clock rate).
The total symbol rate range is divided into 12 sub-ranges. A bit in the above register pair is assigned to each
sub-range, as defined in the tables below. The symbol rate sub-range or sub-ranges to be searched are defined
by setting the appropriate bits high. Small overlaps are automatically provided between successive sub-ranges.
Note that the lowest sub-ranges have been provided for 90 MHz operation and the device has not been
optimised for operation below 1 MBaud.
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ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
