Technical Brief; General Description - LG KB770 Service Manual

3. TECHNICAL BRIEF

3.1 General Description

The KB770 supports UMTS-2100, GSM-900, DCS-1800, and PCS-1900 based
GSM/GPRS/EDGE/UMTS. All receivers and the UMTS transmitter use the radioOne[1]Zero-IF
architecture to eliminate intermediate frequencies, directly converting signals between RF and
baseband. The quad-band GSM transmitters use a baseband-to-IF up-conversion followed by an
offset phase-locked loop that translates the GMSK-modulated or 8-PSK-modulated signal to RF.
• UMTS Cell + PCS with Rx
diversity IMT primary only
• Quad-band EDGE/GPRS
• Simultaneous-GPS
• EDGE/GPRS Tx/Rx and
WCDMA Tx are on the
RTR6275 IC
• One high-band WCDMA Rx is
on the RTR6275 IC
• Two PLLs on the RTR6275 IC:
– One for EDGE/GPRS Tx/Rx
and WCDMA Tx
– One for WCDMA Rx
• GPS pre-LNA within RFR
• UHF VCOs within RFR
• Two PLLs within RFR:
– One for primary and
diversity receive path
– One for GPS
• LO buffers, etc. within RFR
• No RTR/RFR LO interfaces
– No External VCOs
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
H- BPF
L- BPF
U850
U800/ 850
T
Tx BPF
R
Primary
U1900
T
Antenna
R
U2100
U 2100
T
Tx BPF
R
G 850 Rx
G 900 Rx
G 1800 Rx
G 1900 Rx
UMTS Diversity
&
GPS Antenna
GPS
U800 / 850
U1900
Figure 3.1 Block diagram of RF part
- 17 -
3. TECHNICAL BRIEF
LPF
BPF
Quadrature
Upconverter
BPF
SAW
BPF
Quadrature
U1900 Upconverter
BPF
Tx BPF
Power LO Generation
Detector & Distribution
G 850 &
G900
Quadrature
Rx BPFs Downconverter
G 1800 &
G1900 Quadrature
Rx BPFs Downconverter
1
U 2100
Quadrature
Downconverter
Rx BPF
LO Generation
& Distribution
PLL0
CDMA
VCOs
PCS
BPF
LNA
Cell
BPF
LNA
GPS
GPS
Quad
BPF
Rx BPF
D'convert
Pre -
LNA
Cell
Quad
Rx BPF
D'convert
PCS
Rx BPF
RFR6500
LPF
DAC _ REF
LPF
F ref RFR6275_ TCX O
F ref
PLL #1
VCO
LP F & DC
Correction
RTR6275
LP F & DC
Correction
V DDM
ctls
F ref
PLL #2
VCO
RFR6 500_TCX O
F ref
VDDM
F ref
SBI( s )
ctls and
other
Diversity
status
Rx VCO
control
LO Gen
& Dist
LP F
Quad
P rimary path
D'convert
LP F
2
Jammer
detect
LP F
S econdary path
LP F
MSM_ TCXO
Diversity
Rx VCO
GP S
LO Gen VCO
& Dist
P LL1
F ref
LGE Internal Use Only