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NEM-4
Company Confidential
RF Troubleshooting
CCS Technical Documentation
Page 6(b)-68
Copyright
2003 Nokia Corporation
Issue 1 09/2003
Company Confidential
Rx Signal paths
The signal paths of the receiver are shown in following block diagram. Note that the pic-
ture shows EGSM900 (EGSM) receiver (top), GSM1900 (PCS) receiver (middle) and
GSM1800 (DCS/PCN) receiver (down).
Antenna switch (RX/TX Switch)
From the antenna-pad (X600) the RF signal is fed through the antenna connector (X602)
to the RX/TX switch (Z601). The antenna connector represents a mechanical switch
between internal antenna and external antenna feed.
The RX/TX switch (Z601) works as diplexer. EGSM900 input signals pass to GSM_Rx out-
put. GSM1800 input signals pass to PCN_Rx output or PCS_Rx output, depending on the
control signal VANTH (Cont2).
From RX1-GSM output of the antenna switch the RX signal is routed in the inner layers
of the PWB to the EGSM900 SAW filter (Z604). From RX2-DCS output the GSM1800 RX
signal is routed to the GSM1800 SAW filter (Z602). From RX3-PCS output the RX
GSM1900 signal is routed to the GSM1900 SAW filter (Z603).
INPL
INML
INPM
INMM
RXQP
RXIP
VANTL / VANTM / VANTH
VD
DR
XB
B
Mjølner
VRX
INPH
INMH
RXIM
RXQM
Rx
supply
filter
VR6
VR4
SAW
SAW
Ant
Swi
tch
RX900
SAW
RX
PCS
TX
GSM
RX
TX
RX
PCN
3
RX1800
RX1900
1/2
1/4
2
2
2
2
LPF1
DCN1
RF
Controls
RF
Controls
BBAMP
BBAMP
AGC
LPF2
LPF1
DCN1
AGC
LPF2
VD
DR
XF
BIQUA
D
BIQUA
D
DCN2
DCN2
LNA
LNA
LNA
Pre-
gain
Pre-
gain
VDDDIG
LNA
Bias
VDDRXBB
VDDLO