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LGE Internal Use Only
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3. H/W Circuit Description
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Locosto features a fully integrated constant-gain direct conversion receiver, i.e. there is no
interstage filter needed and the baseband level at the analogue IQ- interface follows directly the RF
input level. Depending on the baseband ADC dynamic range, single- or multiple-step gain switching
schemes are possible.
An integrated, selfaligning, low-pass filter ensures the receivers to function under blocking and
reference interference conditions and avoids aliasing by baseband sampling. An automatic DC-
offset compensation is implemented and can beswitched depending on the gain setting.
3.9 RF Interface
Figure 3-9-1. FEM interface
1000p
C431
C433
1000p
V_EXTH
C432
1000p
21
VDD
18
GND7
22
GND8
GSM1800_1900_TX
15
GSM1800_RX1
3
4
GSM1800_RX2
GSM1900_RX1
1
2
GSM1900_RX2
17
GSM850_900_TX
GSM850_RX1
7
8
GSM850_RX2
GSM900_RX1
5
6
GSM900_RX2
23
NC1
24
NC2
19
VC1
VC2
20
FL400
LMSP43QC-789TEMP
11
ANT
GND1
9
GND2
10
12
GND3
GND4
13
14
GND5
GND6
16
ANT_SW1
ANT_SW2