LG VX8500 Service Manual page 28

VX8500
CHAPTER 3. Circuit Description
1. RF Transmit/Receive Part
1.1 Overview
The TX and RX part employs the Direct-Conversion system. The TX and RX frequencies are
respectively 824.04~848.97 and 869.04~893.97 for cellular and 1850~1910 and 1930~1990 for
PCS. The block diagram is shown in [Figure 1-1]. RF signals received through the antenna are
seperated by the Triplexer.
RF Signal fed into the low noise amplifier in RFR6500(LNA) through the duplexer. Then, they are
fed into Mixer in RFR6500. In RFR6500, the RF signal is changed into baseband signal directly.
Then, this signal is changed into digital signal by the analog to digital converter (ADC, A/D
Converter), and the digital circuit part of the MSM(Mobile Station Modem) 6500 processes the
data from ADC. The digital processing part is a demodulator.
In the case of transmission, RFT6150 receives OQPSK-modulated anlaog signal from the
MSM6500.
The RFT6150 connects directly with MSM6500 using an analog baseband interface. In RFT6150,
the baseband quadrature signals are upconverted to the Cellular or PCS frequency bands and
amplified to provide signal drive capability to the power amp.
After that, the RF signal is amplified by the Power Amp in order to have enough power for
radiation. Finally, the RF signal is sent out to the cell site via the antenna after going through
the duplexer.
AWT6310
DCN
R-TAP
MAX2205
DCN
EBS+T
HDET
Dual PAM
PCS PCS
R-TAP
U106
PMIC
MAX1829
Li-Ion Linear
Charger Control
LDO X 8
Thermal
Shutdown
ON/OFF Control
& I2C I/F
DP100
CDMA
Antenna DCN
LM56C
Duplexer
CDMA RF
PCS
connector
Duplexer
FSLF-080HR
U102 ACMD-7402
DP101
GPS
Antenna
GPS BPF GPS Pre-LNA
GPS RF
B7839
ALM1106-TR1
connector
U103
LG Electronics Inc.
[Figure 1-1] Block Diagram of VX8500
B9003
DCN BPF
B9014
LO Gen &Dist
Gain
PCS BPF Control
Circuits
Tx VCO
RFT6150
Scaled Batt
Monitor
U108
RESET
DC-DC
Loop Filter
I2C control
for CDMA Tx
(From MSM6500)
USB TCVR
UVLO
F
ref
Loop Filter PLL 0
for CDMA Rx
Diversity
Rx VCO
LO
F102
Gen
&Dist
CDMA VCOs
B7838
DCN BPF
B7847
Primary Path
PCS BPF
F103
B7840
GPS BPF
F101
Secondary Path
Diversity
Rx VCO
LO Gen
&Dist
RFR6500
F
ref
U107
35
MSM
EBI1
Tx_I MSM Core
JTAG I/F
ARM926EJS
with Jazelle
EBI2
Tx_Q
PLL
Modem
QDSP4000
QDSP4000
SBI Control
Processors
CDMA
Processor 1X,
1X EV-DO
GSM/GPRS
Processor
T PLL
X
gpsOne
Processor
Bluetooth 1.1
Buffer
Processor
KIC7SZ04FU
Tx DAC
SBI
Ref.
X100
Rx ADC
TCXO
ERF3003B
Dual Memory
F
ref
Buses
EBI1
EBI2
SBI Control
MSM6500
Connectivity
Image Sensor
Keypad I/F
SD/SDIO
Rx0_I
USB On The
Go
UART1
Rx0_Q
UART2/RUIM1
UART3/RUIM2
Audio
Rx1_I
MP3, AAC,
EVRC, QCELP
AMR, CMX,
Rx1_Q
MIDI
Video
MPEG-4
H.263, H.264
Graphics
OpenGL? ES
3D, 2D
GPS VCO
Camera
PLL1
Processing
Loop Filter
for GPS
DSP
MCP
DSP Core
512MBit ARM9
SDRAM High Speed
Host I/F
PLL
1GBit
32Mbit
NAND
Memory
Memory
Controller
Wolfson
CODEC
CODEC
MPEG4 /
H.263 H/W
WM8973
CODEC
2D Graphics
Real time
JPEG
Sensor I/F
Speaker
Scaler Engine
Recep-
TV ENC I/F
tacle
Main / Sub
(Earjack)
LCD I/F
SBI
Rx ADC
MIC
MV8620
Connectivity
INTR Control
1.3M CMOS,
WDT / Timer
Audio I/F(I2S)
USB1.1
I2C
GPIO
SD / MMC / T-
Micro SD
Flash / NAND
Touch
Flash
Key
Sensor
LCD
1 2 3
512Mbit
2.0뮃
NAND
4 5 6 QVGA
7 8 9
*
0 #
Receptacle
Keypad
Stereo
Headset
From WM8973
USB
RB04
UART
Bluetooth
RF
CHARGER
Module