Nokia 616 Service Manual page 257

Nokia Customer Care
ture shows EGSM900 (EGSM) receiver (top) and GSM1800 (DCS/PCN) receiver. The GSM
1900 is not used within TF-4.
SAW
INPL
RX900
RX
INML
GSM
TX
RX SAW
INPH
PCS
RX1900
INMH
TX
PCN
SAW
INPM
RX
RX1800
INMM
VANTL / VANTM / VANTH
3
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.
Issue 2.0 Mar/2005
Company Confidential
VR6
LNA
Bias
Pre-
LNA
gain
Pre-
LNA
gain
2 2
2
LNA
VDDDIG
1/2 1/4
RF
Controls
VDDRXBB
RF
Controls
Copyright © 2005 Nokia Corporation.
Company Confidential
TF4 Technical Information
supply
BBAMP
LPF1
BBAMP
LPF1
2
TFE-4/RV-1
Rx
filter
BIQUA
D
DCN1 AGC
DCN2
LPF2
BIQUA
D
DCN1 AGC
DCN2
LPF2
Mjølner
Page 8b-53
VRX
VR4
RXIP
RXIM
RXQP
RXQM
VDDLO