LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
The inputs use differential configurations to improve second-order intermodulation and common-mode
rejection performance. The differential input gain stage implements MSM IC-controlled gain
adjustments to extend receiver dynamic range.
The outputs of the differential amplifiers drive the RF port of the quadrature RF-to-baseband down-
converters. The down-converters are routed to low-pass filters (one I and one Q) whose pass-band and
stop-band characteristics supplement MSM device processing. These filter circuits allow for DC offset
correction and the differential I/Q outputs are buffered to interface with the MSM IC.
Numerous secondary functions also are integrated on-chip: the Rx LO generation and distribution
circuits and various interface, control, and status circuits. An on-chip UMTS VCO is phase locked to the
external VC-TCXO signal and processed, by the LO generation and distribution circuits, to create the
UMTS Rx LO signals for the quadrature down-converter. The LO signal, applied to its mixer, is at
frequencies different to that of the VCO, which is an important consideration for ZIF processing. The
QUALCOMM MSM device provides status and control signaling, employing power reduction features
(such as selective circuit power-down, gain control, and bias control) to extend handset standby time.
3. TECHNICAL BRIEF
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Figure 3.3.2 RTR6275 IC functional block diagram
WCDMA_2100_RX
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