Functional Description - Panasonic GSM EB-A100 Service Manual

5.1.3. Functional Description

Frequency Plan
The frequency plan is shown below:
TX Frequency Plan
E-GSM 900
GSM 1800
PCS 1900
F
VCO
Where k is 1 for low band and 2 for high band.
Fractional-N
PLL
General
RF circuit design is built based on SKYWORKS-74963 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. And LO frequency is periodically re-tuning to synchronize
with cell or network.
Antenna
EB-A100 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.
TX Frequency
880.2 MHz - 914.8 MHz
1710.2 MHz - 1784.8 MHz
1850.2 MHz - 1909.8 MHz
RX RF from
LNA
3
= F
RX
2k
F
VCO
UHF VCO
Figure 5.2. Receiver Block Frequency Plan
TX IF
88.46 MHz - 114.35 MHz
90.316 MHz - 104.776 MHz 1354.737 MHz - 1414.482 MHz
97.379 MHz - 112.341 MHz 1460.684 MHz - 1516.606 MHz
F
RX
90°
x 1
/3
x 2
k = Frequency muliplier
– 5-3 –
TX RF LO
1459.59 MHz -1543.725 MHz
RX I
90°
x 2
RX Q