General Description - LG U8120 Service Manual

3.6 General Description

The RF part includes a dual-band GSM/DCS part (900 and 1800MHz) and W-CDMA part for IMT-2000
(UL 1900MHz, DL 2100MHz). It also contains Antenna Switch, WCDMA duplexer, WCDMA Power
Amplifier and GSM Power Amplifier.
The whole structure of Radio part is shown in Figure 3-1.
Antenna
Test po int
Isola to r
Antenna Switch
Starting at the antenna end, an antenna switch provides switching capability needed for three
frequency bands (900, 1800 and 2100MHz). For the W-CDMA part, duplexer is included to facilitate
the simultaneous transmission and reception required for the FDD mode.
The main components in the radio are Wopy (W-CDMA receiver ASIC), Wivi(W-CDMA transmitter
ASIC), Ingela(GSM/GPRS transceiver) and two power amplifiers.
The mixed-signal circuit ASIC, Vincenne provides power supply for the main RF components.
UMTS RX SAW
UM TS Wopy
Duplex er
UMTS PA
UMTS TX SAW
DC/DC
Ro sa lie
DCS RX SAW
GSM RX SAW
GSM Dual PA
DCS Ba lun
GSM Balun
Figure 3-1. Block diagram of RF part
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3. TECHNICAL BRIEF
UMTS RX IF SAW
RF PLL
/VCO
Tank
UM TS Wivi
÷
GSM Ingela
÷
XO
Dio de
XO (13 MHz)
IF PLL/VCO
ADC
ADC
Clk
GSM Herta
Loo p
PD
filter
Pre-
scaler