User Manual
Airbridge cBTS3612 CDMA Base Station
System Description
2 Hardware Architecture
2-32
Pr-OUT
Pf-OUT
TX1
TX2
RXM-OUT
Combiner
Duplexer
Directional
coupler
RXM-Test
TX-Test
TX/RXM-ANT
Isolator
Isolator
Figure 2-17
Structure of CDU
l
Isolator
There are two isolators at each input port of the combiner in CDU. They are used to
isolate the two carriers from two input ports.
l
2-in-1 combiner
The combiner is a narrow band cavity filtering combiner. In comparison with
broadband combiner, it features lower insertion loss and effective isolation.
l
Duplexer
The duplexer is used to isolate transmitted signals and received signals, suppress
transmission spurious and reduce antenna quantity.
l
Directional coupler
The directional coupler couples forward/reverse power to RLDU, and monitors the
antenna VSWR.
III. Interface
CDU is a module shared by transmit and receive path of the BTS. It has interfaces
with other modules both in the transmitting and receiving paths. Its external
interfaces include a set of 8W8 D-type combination blind mate connectors on the
backside, and a set of N-connectors and SMA connectors on the front side. The
interface signals include: