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5. Block diagram and work principle
CEW-P10 ~ CEW-P20 is basically a bi-directional amplifier, the downlink signals are received by the repeater
from BTS by the donor antenna, filtered by its internal duplexers and FC unit, amplified by low noise amplifier (LNA)
and downlink PA unit, and then sent via the server antenna to the coverage area. The bandwidth is operators’
working frequency only.
The uplink signal of mobile terminal from the coverage area is input via the server antenna, then filtered by
duplexers and FC unit, amplified by the uplink low noise amplifier (LNA) and the uplink PA unit and finally sent via
the donor antenna to the BTS.
Modules in the system diagram:
Duplexer:
The main purpose of duplexer is to combine downlink and uplink to share the same
antennas, the duplexer is composted of one pair of band pass filter that can not only reject the
spurious interference, but also increase the isolation of Uplink and Downlink
LNA:
LNA is the first active sub system of the repeater, of which low noise and high linearity is
requested under strong input signals. LNA is the major sub system that determines the noise figure
of the repeater system.
IF Filter:
IF SAW filer is adopted in FC sub system to reject signals of other operators to make sure
the signals clean and increase the UL and DL isolation.
PA:
The power amplifier sub system helps the repeater to reach its targeted output power, linearity
of which decides the linearity of the repeater
Power supply
is to supply power electricity to all repeater’s modules
