LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
- 93 -
4.13.4. Checking RX I/Q Signals
Figure 12. RX I/Q Circuit
Checking Flow
Checking Points
C434
0.1u
X400
26MHz
GND1 2
4
GND2
HOT1
1
3
HOT2
NX3225SA
VDDRX2V8
20
35
VDDTX1V5
VDDTX2V8
38
VDDVCO2V8
17
15
VDDXO2V8
11
XO
XOX
12
RX2
27
28
RX2X
24
RX3
RX3X
25
22
RX4
RX4X
23
TX1
36
TX2
37
VBIAS
34
18
VCO_RC
VDDBIAS2V8
31
VDDDIG1V5
8
5
VDDDIG2V8
VDDLNA1V5
21
39
VDDMIX2V8
19
VDDRX1V5
3
B
BX
4
7
CLK
DA
6
EN
16
32
FE1
33
FE2
FSYS1
14
FSYS2
10
9
FSYS3
GND1
13
26
GND2
GND3
40
41
GND4
RX1
29
30
RX1X
PMB6272
U401
1
A
AX
2
C435
0.1u
R410
820
0.1u
C433
47n
C437
I
IX
Q
QX
RF_CLK
RF_DA
BT_CLK
Check RX I/Q signals(TP1~TP4)
Signals are
Normal?
Replace
Transceiver
PMB6272(U403)
Yes
No
RX Part is OK.
Check Base Band Circuit
or
Re-Download S/W and Cal
U401
TP1(I)
TP2(IX)
TP3(Q)
TP4(QX)
I
I
Q
Q
RX
Figure 14. RX I/Q Waveform
Figure 13. RX I/Q
TP1(I)
TP2(IX)
TP3(Q)
TP4(QX)