– 5–3 –
5.1.3. Functional Description
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Frequency Plan
The frequency plan is shown below:
Figure 5.2. Receiver Block Frequency Plan
TX Frequency
TX Frequency Plan
TX IF
TX RF LO
E-GSM 900
880.2 - 914.8MHz
88.46 - 114.35MHz
1459.59 -1543.725MHz
GSM 1800
1710.2 - 1784.8MHz
90.316 - 104.776MHz
1354.737 - 1414.482MHz
PCS 1900
1850.2 - 1909.8MHz
97.379 - 112.341MHz
1460.684 - 1516.606MHz
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General
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Antenna
EB-G50 uses Helical-type antenna, which is most low-cost, monopole-like antenna. The antenna takes different
spacing to define bands of GSM, DCS and PCS.
RF circuit design is built based on SKYWORKS-74063 direction conversion transceiver IC integrated by SAW filters,
power amplifier with control circuit, and Transmitter/receiver switch.
RF LO always requires external frequency sources with VCTCXO in VE2. And LO frequency is periodically re-tuning to
synchronize with cell or network.
F
VCO
= F
RX
3
2k
F
RX
F
VCO
UHF VCO
k = Frequency muliplier
Where k is 1 for low band and 2 for high band.
101959A 2_020802
x 1
x 2
x 2
/3
90
°
90
°
RX RF from
LNA
Fractional-N
PLL
RXQ
RXI