Radio Transceiver Section - Pantech G800 Service Manual

G800 Service Manual

4.2. Radio Transceiver Section

Fig.4-1. RF Transceiver block diagram
The G800's RF Transceiver(U710), which is AERO I, consists of the GSM transmitter,the GSM Receiver, and
the RF synthesizer. The highly integrated solution eliminates the IF SAW filter, external low noise amplifiers
(LNAs) for three bands, transmit and RF voltage controlled oscillator (VCO) modules, and more than 60 other
discrete components found in conventional designs.
The receive section uses a digital low-IF architecture that avoids the difficulties associated with direct
conversion while delivering lower solution cost and reduced complexity.
The transmit section is a complete up-conversion path from the baseband subsystem to the power amplifer
(U701) and uses an offset phase locked loop (PLL) with a fully integrated transmit VCO.
The RF synthesizer includes integrated RF and IF VCO's, Varactors, and Loop filters. The unique integer-N
PLL architecture used in the RF synthesizer produces a transient response that is superior in speed to
fractional architectures without suffering the high phase noise or spurious modulation effects often associated
with those designs.
The following Figure shows G800's top view of PCB artworks.
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R&D CONFIDENTIAL