LG HB620, Service Manual

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3. TECHNICAL BRIEF
3. TECHNICAL BRIEF
LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.1 General Description
The HB620T supports UMTS-2100, EGSM-900, DCS-1800, and PCS-1900 based
GSM/GPRS/EDGE/UMTS. All receivers and the UMTS transmitter use the radioOne
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Zero-IF
architecture to eliminate intermediate frequencies, directly converting signals between RF and
baseband. The quad-band GSM transmitters use a baseband-to-IF upconversion followed by an offset
phase-locked loop that translates the GMSK-modulated or 8-PSK-modulated signal to RF.
A generic, high-level functional block diagram of HB620T is shown in [Fig. 3.1]. One antenna collects
base station forward link signals and radiates handset reverse link signals. The antenna connects with
receive and transmit paths through a FEM(Front End Module).
The UMTS receive paths each include an LNA, an RF band-pass filter, and a downconverter that
translate the signal directly from RF-to-baseband using radio One ZIF techniques. The RFIC’s Rx
analog baseband outputs, for the receive chains, connect to the MSM IC. The UMTS and GSM Rx
baseband outputs share the same inputs to the MSM IC.
[Fig. 3.1] Block diagram of RF part
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QUALCOMM’s branded chipset that implements a Zero-IF radio architecture.
Z3X-BOX.COM