TECHNICAL DESCRIPTION
Issue 1
Section 4
PMCD030901C8
Revision 0
– 10 –
Service Manual
4.1.3.
Block Diagram
Figure 4.1: RF Block Diagram
4.1.4.
Frequency Plan
Figure 4.2: Frequency Plan
4.1.5
Synthesiser
Transceiver IC U603 has a synthesiser and VCO for generating appropriate signals for the transmitter and receiver. Channel
data is transferred to IC603 from the baseband IC by three-wire bus (Data, Clock and Strobe). Signal output is divided by 4 for
EGSM 900 and by 2 for GSM 1800 / GSM 1900. Synthesiser lock time is approximately 180
µ
s.
An external TCXO is used to generate a 26 MHz reference signal for the transceiver and logic block. AFC is employed to
maintain stability over changes in temperature.
EGSM 900
GSM 1900
GSM 1800
HPF
LPF
Rx
Tx
Rx
Tx
Rx
Tx
FRONT END
(SWITCH MODULE)
IR
IRX
QR
QRX
BASEBAND
AMPLIFIERS
BASEBAND
FILTERS
TRIPLE BAND TRANSCEIVER
PGC
AMP
RF
LO
LNA
LNA
LNA
10699-1
ATTENUATORS
BUFFER AMP
÷2
APC
COUPLER
COUPLER
I
Q
I
Q
RF
VCO
EGSM 900
GSM 1800 / 1900
TRIPLE
BAND
PA
PA RAMP
900
1800 /
1900
÷4
Rx: 925 - 960 MHz
RFLO VCO
3520 - 3840 MHz
Tx: 880 - 915 MHz
I, Q output
to baseband
I, Q output from
baseband
1/4
925 - 960 MHz
880 - 915 MHz
Rx: 1805 - 1880 MHz
RFLO VCO
3420 - 3760 MHz
Tx: 1710 - 1785 MHz
I, Q output
to baseband
I, Q output from
baseband
1/2
1805 - 1880 MHz
1710 - 1785 MHz
Rx: 1930 - 1990 MHz
RFLO VCO
3700 - 3980 MHz
Tx: 1850 - 1910 MHz
I, Q output
to baseband
I, Q output from
baseband
1/2
1930 - 1990 MHz
1850 - 1910 MHz
E-GSM 900
GSM 1800
GSM 1900
10655-1
Summary of Contents for EBX70 - CELL PHONE
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