Panasonic EB-X70 Service Manual page 12

TECHNICAL DESCRIPTION
4.1.3. Block Diagram
FRONT END
(SWITCH MODULE)
LPF
Rx
Tx
Tx
Rx
HPF
Tx
Rx
10699-1
4.1.4. Frequency Plan
E-GSM 900
I, Q output
to baseband
Rx: 925 - 960 MHz
925 - 960 MHz
RFLO VCO
1/4
3520 - 3840 MHz
880 - 915 MHz
I, Q output from
Tx: 880 - 915 MHz
baseband
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 µs.
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.
Issue 1
Revision 0
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TRIPLE BAND TRANSCEIVER
EGSM 900
GSM 1800
GSM 1900
EGSM 900
COUPLER
TRIPLE
ATTENUATORS
BAND
PA
COUPLER
GSM 1800 / 1900
APC
PA RAMP
Figure 4.1: RF Block Diagram
GSM 1800
Rx: 1805 - 1880 MHz
RFLO VCO
1/2
3420 - 3760 MHz
Tx: 1710 - 1785 MHz
Figure 4.2: Frequency Plan
Section 4
– 10 –
LNA
PGC
AMP
RF
LO
LNA
LNA
BUFFER AMP
900
1800 /
1900
I, Q output
to baseband Rx: 1930 - 1990 MHz
1805 - 1880 MHz
RFLO VCO
3700 - 3980 MHz
1710 - 1785 MHz
I, Q output from
Tx: 1850 - 1910 MHz
baseband
BASEBAND
FILTERS
IR
IRX
BASEBAND
AMPLIFIERS
QR
QRX
RF
VCO
÷4
I
Q
÷2
I
Q
GSM 1900
I, Q output
to baseband
1930 - 1990 MHz
1/2
1850 - 1910 MHz
I, Q output from
baseband
10655-1
PMCD030901C8
Service Manual