- 76 -
LGE Internal Use Only Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3. Technical brief
3.7.4. Front-End Module (FEM)
A single antenna is used for all four bands. The antenna switch and the EDGE/GSM/GPRS
power amplifiers are integrated to a single circuit containing:
. Antenna Switch with support for W-CDMA band 1
. Power amplifiers for high and low band EDGE/GSM/GPRS
. AM modulator/control circuit
. Low pass transmitter filtering
The antenna switch block connects the proper block in the radio system to the antenna
connection. In GSM/GRPS/EDGE systems, transmit and receive operations are divided in time,
and the switch connects the proper block in accordance with the mode of operation (that is,
transmit or receive; one at a time in the GSM, DCS, and PCS bands).
In W-CDMA systems, the transmitter and the receiver operate simultaneously (that is, full
duplex). The switch is used only for selecting the W-CDMA mode of operation . the split
between transmit and receive frequencies is handled by the W-CDMA duplexer.
Figure 3-7-8. Front-End Module
To Next Page
Loading...
