Receiver Part; Only For Training And Service Purposes - LG KC780 Service Manual

3. TECHNICAL BRIEF

3.20. Receiver part

The constant gain direct conversion receiver contains all active circuits for a complete receiver chain for
GSM/GPRS/EDGE (see Figure 30). The GSM850/900/DCS1800/ PCS1900 LNAs with balanced inputs are fully
integrated. No inter-stage filtering is needed. The orthogonal LO signals are generated by a divider-by-four for
GSM850/900 band and a divider-by-two for the DCS1800/PCS1900 band. Down conversion to baseband
LGE Internal Use Only
VBAT
BAT_ID
RF_TEMP
TP105
REMOTE_ADC
TXHB
TXLB
GSM850_RXP
GSM850_RXN
GSM900_RXP
GSM900_RXN
PA_BAND
DCS1800_RXP
PA_MODE
DCS1800_RXN
VC1
VC2
PA_EN
PCS1900_RXP
TX_RAMP
FB180
PCS1900_RXN
PA_EN_LED UART_BT_RTS
Figure 33 TX IQ
Figure 34. Receiver Block Diagram of S-GOLDradio
- 62 -
C129
0.1u
H3
M0
J3
M1
G4
M2
H4
M7
G3
M8
J4
M9
F4
M10
W3
TX2
V3
TX1
W2
RX1
V1
RX1X
U1
RX2
T1
RX2X
R3
PABIAS
R4
PABS
R1
RX3
T5
VDET
U5
PAMODE
P1
RX3X
N4
FE1
P5
FE2
M3
PAEN
N1
RX4
P3
VRAMP
M1
RX4X
A18
T_OUT3
J10
Copyright © 2008 LG Electronics. Inc. All right reserved.

Only for training and service purposes