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4. RF circuit technical brief
4.5 DCXO
The transceiver contains a fully integrated 26MHz digitally controlled crystal oscillator (DCXO) with
three outputs for the system clock, one output for the GSM baseband and two additional for other
subsystems (GPS, Bluetooth, etc.). The only external part of the oscillator is the crystal itself. The
overall pulling range of the DCXO consists of eight subranges. The subrange closest to the ‘0ppm’ at
the middle AFC-value is selected during the calibration process in the mobile’s production and is used
for the rest of the lifetime. The frequency tuning is performed along the selected subrange by
programming the frequency control word (XO_TUNE) via the three wire bus (“3Wbus”).
4.6 Front End Module control
Implemented in the Transceiver are two outputs for direct control of front end modules with two logic
input pins to select RX- and TX-mode as well as low- and high band operation.
LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
EGSM900 RX
GSM850 RX
L
GSM850
DCS_PCS TX
GSM850_EGSM TX
H
L
PIN 14
L
PIN 13
L
L
PCS1900 RX
L
PCS1900
VC2
DCS1800 RX
L
L
L
DCS1800
GSM900
VC1
H
L
R504
100p
2.2nH
R596
33p
C500
C513
2.7p
NA
L585
18nH
L502
5.1nH
L504
3.3p
C518
L505
3.9nH
1
R501
C503
120p
15p
C519
10nH
L584
15nH
L503
5.6p
C515
3.3p
C517
DUMMY
FEED
15
GSM1800_1900_TX
7
GSM1900RX_OUT1
GSM1900RX_OUT2
8
GSM850RX_OUT1
1
GSM850RX_OUT2
2
17
GSM850_900_TX
3
GSM900RX_OUT1
GSM900RX_OUT2
4
21
NC
19
VC1
VC2
20
ANT501
LSHS-C085FB
U501
11
ANT
GND1
9
24
GND10
GND2
10
12
GND3
GND4
13
GND5
14
GND6
16
18
GND7
22
GND8
23
GND9
GSM1800RX_OUT1
5
GSM1800RX_OUT2
6
C520
15p
KMS-512
SW500
ANT
G1
G2
RF
C514
2.7p
1
R500
C516
5.6p
NA
L583
VC2
VC1
GSM850_RXP
GSM900_RXP
DCS1800_RXP
DCS1800_RXN
PCS1900_RXP
PCS1900_RXN
GSM850_RXN
GSM900_RXN
Figure 36. FEM Circuit Diagram
Содержание KC550
Страница 1: ...Date May 2008 Issue 1 0 Service Manual Model KC550 Service Manual KC550 Internal Use Only ...
Страница 129: ... 130 LGE Internal Use Only Copyright 2008 LG Electronics Inc All right reserved Only for training and service purposes ...
Страница 155: ...LGE Internal Use Only Copyright 2008 LG Electronics Inc All right reserved Only for training and service purposes 156 ...
Страница 182: ...Note ...
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