LG CE500 Service Manual page 30

Mobile Switch & FEM (Front End Module)
• From DBB, three control signals (VC1, VC2, VC3) are fed into the FEM.
Control Logic
VC1
L
H
L
L
H
❖ Pre-Burst TX 1900
: For enhanced Ant-RX1800 isolation during Pre-burst time for TX1900
VC2 VC2
L L
L L
H H
L H
H H
- 31 -
3. Technical Brief
TP701(VC1)
TP702(CC2)
TP703(VC3)
Switch Mode
GSM850/DFCS/PCS Rx
GSM850 Tx
DCS/PCS Tx
Pre-burst Tx 1900
unused