Nokia 2600 服务手册
ISSUE 1 09/2004
COMPANY CONFIDENTIAL
25
Copyright © 2004 Nokia. All Rights Reserved.
RH-59/60
7-System Module
Nokia Customer Care
General Description of the RF circuits
In the following general descriptions different colours are used in the block diagram. The Low
band signal route is shown in red, theHigh band route in green and the common signal lines
are shown in blue.
band signal route is shown in red, theHigh band route in green and the common signal lines
are shown in blue.
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Receiver signal path
The signal from the antenna pad is routed to the RX/TX switch (Z700). If no control voltage is
present at VANT2 and VANT1 the switch works as a diplexer and the low band signal is passed
through the RX/TX switch to GSM-RX and theHigh band signal is passed to DCS-RX.
present at VANT2 and VANT1 the switch works as a diplexer and the low band signal is passed
through the RX/TX switch to GSM-RX and theHigh band signal is passed to DCS-RX.
Figure 10: Receiver signal path
From the RX/TX switch the low band signal is routed to the SAW filter (Z602). The front end of
Mjoelner is divided into a LNA and Pre-Gain amplifier before the mixers.
Mjoelner is divided into a LNA and Pre-Gain amplifier before the mixers.
The output from the mixer is feed to Baseband part of Mjoelner where the signals amplified in
the BBAMP and low pass filtered in LPF1 before the DC compensation circuits in DCN1. The
DCN1 output is followed by a controlled attenuator and a second lowpass filter LPF2. The out-
put from LPF2 is feed to the BB for demodulation.
the BBAMP and low pass filtered in LPF1 before the DC compensation circuits in DCN1. The
DCN1 output is followed by a controlled attenuator and a second lowpass filter LPF2. The out-
put from LPF2 is feed to the BB for demodulation.
TheHigh band signal chain is similar to low band, the SAW filter numbered Z601.