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4.12.3. Checking TX I/Q Signals
F
E
2
3
3
V
B
A I
S
3
4
V
D
D
T
X
1
V
5
V
D
D
3
5
T
X
1
V
D
D
U
4
0
2
3
6
T
X
2
V
P
M
B
6
2
7
2
3
7
V
D
D
T
X
2
V
8
V
D
D
V
3
8
V
D
D
M
X I
2
V
8
3
9
G
N
D
3
V
D
D
4
0
G
N
D
4
4
1
TP1(I)
TP3(Q)
TP2(IX)
TP3(Q)
TP1(I)
TP2(IX)
TX I/Q Circuit
TX I/Q Circuit
Checking Points
TX I/Q
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
2
V
8
5
_
V
R
F
1
V
5
_
V
R
F
C
4
3
1
C
4
3
2
C
4
3
3
0
1 .
u
0
1 .
u
0
1 .
u
R
X
2
V
8
2
0
C
4
3
5
R
X
1
V
5
1
9
R
4
0
7
4
7
n
C
O
_
R
C
1
8
8
2
0
C
O
2
V
8
1
7
E
N
1
6
X
O
2
V
8
1
5
F
S
Y
S
1
1
4
G
N
D
1
1
3
TP4(QX)
X
4
0
0
N
X
3
2
2
5
S
A
TP4(QX)
4
3
G
N
D
2
H
O
T
2
1
2
H
O
T
1
G
N
D
1
2
6
M
H
z
I S
M
1
_
B
T
_
C
L
K
2
6
M
_
O
U
T
_
T
E
S
T
R
F
_
C
L
K
R
F
_
D
A
Q
X
Q
X I
I
TP1(I)
TP4(QX)
TP2(IX) TP3(Q)
U401
Checking Flow
Checking Flow
Check TX I/Q Signals(TP1~TP4)
Check TX I/Q Signals(TP1~TP4)
Signals are
Signals are
Normal ?
Normal ?
Yes
TX Part is OK.
TX Part is OK.
Check Base Band Circuit
Check Base Band Circuit
or
or
Re-Download S/W and Cal
Re-Download S/W and Cal
I
Q
I
Q
TX I/Q Waveform
- 105 -
4. TROUBLE SHOOTING
Replace
Replace
No
No
Transceiver
Transceiver
PMB6272(U401
PMB6272(U401)
Yes
TX
LGE Internal Use Only
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Troubleshooting
