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Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. TECHNICAL BRIEF
G
3.5 GSM MODE
The EDGE/GPRS/GSM transceiver use a digital interface that is shared between receive and transmit data.
The receive interface is based on I and Q data and the transmitter interface is based on envelop and
frequency data.
The quad band EDGE/GSM/GPRS transceiver has the following general features:
Power class
GMSK low bands: Class 4 (33 dBm)
GMSK high bands: Class 1 (30 dBm)
8PSK low bands: Class E2 (27 dBm)
8PSK high bands: Class E2 (26 dBm)
Multi slot class 12 (4+4=5)
Dual Transfer Mode (DTM) class 9 (3+2=5)
Zero-IF receiver
-Polar modulation transmitter
3.5.1 GSM RECEIVER
The RF receiver designs are leveraged from previous-generation RTR devices, including the latest innovations.
All ESC receiver paths are discussed in this section.
The ZIF receive signal paths support multiband, multimode applications:
Quad-band GSM:
Low-band
GSM 850 (869 to 894 MHz) and GSM 900 (925 to 960 MHz)
High-band
DCS1800 (1805 to 1880 MHz) and PCS1900 (1930 to 1990 MHz)
The on-chip receive signal paths are functionally identical for each mode (GSM or EDGE) and each band type
(low or high). The external circuitry includes the antenna switch module and a filter function.
All RF Rx inputs use a differential configuration to maximize common-mode rejection, Tx isolation, out-of-
band suppression, and second-order intermodulation performance. The first of two quadrature
downconverters accepts inputs from two LNAs (only one is active at a time). An example application could
support the following bands using these two LNAs:
GSM 1900
GSM 850