Nokia Customer Care TF4 Technical Information
Company Confidential TFE-4/RV-1
Issue 2.0 Mar/2005 Copyright © 2005 Nokia Corporation. Page 8b-53
Company Confidential
ture shows EGSM900 (EGSM) receiver (top) and GSM1800 (DCS/PCN) receiver. The GSM
1900 is not used within TF-4.
Antenna switch (RX/TX Switch)
From the antenna connector (X602) the signal is fed to the RX/TX switch (Z601).
The RX/TX switch (Z601) works as duplexer. EGSM900 input signals pass to GSM_Rx out-
put. GSM1800 input signals pass to PCN_Rx output. 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). The RX/TX switch with routed lines has following typical
insertion losses:
1.3dB@EGSM900, and 1.6dB@GSM1800.
Front-end
The RX front end includes two SAW filters (EGSM900 (Z604), GSM1800 (Z602)). Each of
the SAW filters is matched with a differential matching circuit (LC-type) to the corre-
sponding LNA input of Mjoelner RF ASIC (N601). The SAW filters provide out-of-band
blocking immunity, the integrated LNAs provide the front-end gains. Each of the SAW fil-
ters has a single-ended input and a balanced output which provides a balanced RX signal
to the corresponding input of the Mjoelner RF ASIC. The SAW filters have maximum
insertion losses of 3.5dB at EGSM900 and 4.0dB at GSM1800 .
RX paths of Mjoelner RF ASIC
The balanced RX signal is amplified by the integrated LNA and the subsequent Pre-Gain
stage. After amplification the RX signal is down-converted with a LO signal coming from
the local oscillator.
The RX paths of Mjoelner RF ASIC consist of following building blocks:
• Separate LNAs for each of the two bands: EGSM900 and GSM1800.
INPL
INML
INPM
INMM
RXQP
RXIP
VANTL / VANTM / VANTH
V
D
D
R
X
B
B
Mjølner
VRX
INPH
INMH
RXIM
RXQM
Rx
supply
filter
VR6
VR4
SAW
SAW
Ant Switch
RX900
SAW
RX
PCS
TX
GSM
RX
TX
RX
PCN
3
RX1800
RX1900
1/2
1/4
2
222
LPF1
DCN1
RF
Controls
RF
Controls
BBAMP
BBAMP
AGC
LPF2
LPF1
DCN1
AGC
LPF2
V
D
D
R
X
F
BIQUA
D
BIQUA
D
DCN2
DCN2
LNA
LNA
LNA
Pre-
gain
Pre-
gain
VDDDIG
LNA
Bias
VDDRXBB
VDDLO
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