LG Electronics LG-C320 Low-band, GSM 850 869 to 894 MHz and GSM 900 925 to 960 MHz, High-band

3. TECHNICAL BRIEF

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

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