W3020 Datasheet, PDF (24/44 Pages) Agere Systems – GSM Multiband RF Transceiver

W3020 GSM Multiband RF Transceiver
Advance Data Sheet
December 1999
Programming Information (continued)
TR Register (continued)
Table 20. FTR: LPF Tune Filter Request
This requests tuning operation of baseband low-pass
filter (see the Low-Pass Filter Tuning section for
details). If the filter tune is enabled in CONFIG
register, the FTR bit must be programmed high before
the first following receive mode is active. Filter tune
can only be done in a mode where LO2 is active, e.g.,
receive mode.
FTR
Bit 15
0
1
Function
Use Default Tuning Value
Perform New Tuning
Table 21. DP: dc Precharge Only
When dc offset calibration is performed, only the
precharge portion is done. This reduces the amount of
time required for dc offset calibration, but gives higher
levels of dc offset. (See the dc Offset Calibration
section for details.)
DP
Bit 14
0
1
Function
Standard dc Offset Correction Cycle
dc Precharge Cycle Only
Table 22. DS: dc Correction Skip
DS
Bit 13
0
1
Function
Insert dc Correction Cycle (See Table
41.)
Skip dc Offset Calibration (with retained
dc correction setting)
Table 23. T2: TX IF LO Division Select Switch
Reverses the LO2 frequency division factor in the
transmitter for both bands. This is provided for testing
purposes. This bit works with the band bit B as follows.
T2
Bit 12
0
0
1
1
B
Bit 23
0
1
0
1
Function
Divide by 2 (270 MHz):
Normal GSM900 Division
Divide by 3 (180 MHz): Normal
GSM1800/1900 Division
Divide by 3 (180 MHz): Reversed
Band 0 Division
Divide by 2 (270 MHz): Reversed
Band 1 Division
Table 24. T1: TX IF LO Divide-by-6 Select
This bit will change the divide-by-3 circuit to a divide-
by-6 circuit. This bit is provided for testing purposes.
T1
Bit 11
0
1
Function
Divide by 3 when 1/3 Path Is Active
Divide by 6 when 1/3 Path Is Active
Table 25. T0: TX IF Duty Cycle Corrector Disable
When high, disables duty cycle correction circuit into
the transmit IF phase splitter. This bit is provided for
testing purposes.
T0
Bit 10
0
1
Function
TX IF LO Duty Cycle Corrector Enabled
TX IF LO Duty Cycle Corrector Disabled
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