LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
The EGSM900, DCS1800, and PCS1900 receive signals are routed to the RTR6235 through band
selection filters and matching networks that transform single-ended 50-Ω•sources to differential
impedances optimized for gain and noise figure. The RTR input uses a differential configuration to
improve second-order inter-modulation and common mode rejection performance. The RTR6235 input
stages include ESMcontrolled gain adjustments that maximize receiver dynamic range.
The amplifier outputs drive the RF ports of the quadrature RF-to-baseband downconverters. The
downconverted baseband outputs are multiplexed and routed to lowpass filters (one I and one Q)
having passband and stopband characteristics suitable for GMSK or 8-PSK processing. These filter
circuits include DC offset corrections. The filter outputs are buffered and passed on to the ESM6270 IC
for further processing
3. TECHNICAL BRIEF
- 18 -
[Fig 3.2.2] RTR6235 RX feature
Содержание KE990 - Viewty Cell Phone 100 MB
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