LG MG120a Service Manual page 18

3. TECHNICAL BRIEF
3.2.2 Transceiver (SI4210, U103)
The SI4210 transceiver is a complete RF front end for multi-band GSM and GPRS wireless
communications. The receive section interfaces between the RF band-select SAW filters and
the baseband subsystem. The Aero II receiver leverages a proven digital low-IF architecture
and enables a universal baseband interface without the need for complex dc offset
compensation. The transmit section of Aero II provides a complete upconversion path from
the baseband subsystem to the power amplifier (PA) using an offset phase-locked loop (OPLL)
integrated with Silicon Laboratories' patented synthesizer technology. All sensitive
components, such as TX/RF VCOs, loop filters, tuning inductors, and varactors are completely
integrated into a single integrated circuit. The Aero II transceiver includes a digitally-controlled
crystal oscillator (DCXO) and completely integrates the reference oscillator and varactor
functionality.
Figure 3-4 Functional Block Diagram
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