LG TracFone LG840G Service Manual page 18

3. TECHNICAL BRIEF
3.2.1 Transmitter Part
k
WCDMA Transmitter Bloc
The QSC62x0 device supports tri-band UMTS transmissions with three separate driver amplifier outputs; in fact, most Tx
active circuits are contained within the device. All three UMTS transmit paths (Figure 3.2.1.1) begin with a single, shared
analog baseband signal from the device's baseband circuits. The baseband signal is composed of two differential lines,
one in-phase component and one quadrature-phase component. Each component is low pass filtered and amplified to
levels sufficient for driving the quadrature upconverters. There are two upconverters — one for low-band signals and one
for high band — but only one upconverter is active at a time.
18page Figure 3.2.1.1 p g g
Figure 3.2.1.1 WCDMA Transceiver Architecture
LGE Internal Use Only - 18 - Copyright © 2012 LG Electronics. Inc. All right reserved.
Only for training and service purposes