3.9 RF Interface
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.
- 29 -
3. HW Circuit Description
LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Figure 3-9-1. FEM interface
V_EXTH
1000p
C433
C431
1000p
NC1
23
NC2
24
VC1
19
20
VC2
VDD
21
GND3
12
13
GND4
GND5
14
16
GND6
GND7
18
GND8
22
15
GSM1800_1900_TX
3
GSM1800_RX1
GSM1800_RX2
4
1
GSM1900_RX1
GSM1900_RX2
2
GSM850_900_TX
17
7
GSM850_RX1
GSM850_RX2
8
5
GSM900_RX1
GSM900_RX2
6
LMSP43QC-789TEMP
FL400
ANT
11
9
GND1
10
GND2
C432
1000p
ANT_SW1
ANT_SW2
Содержание CP150
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