External Interfaces - Huawei Airbridge BTS3612A-1900 Technical Manual

Technical Manual
Airbridge BTS3612A CDMA Base Station
I. 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.
II. Combiner
The combiner is a narrow band cavity filtering combiner. In comparison with broadband
combiner, it features lower insertion loss and effective isolation.
III. Duplexer
The duplexer is used to isolate transmitted signals and received signals, suppress
transmission spurious and reduce antenna quantity.
IV. Filter
The filter on the transmitting channel filters transmitting signal.
The filter on the main/diversity receive channel filters main/diversity receive signals
respectively. Then it sends them to low-noise amplifier in the RLDU for amplification.
V. Directional coupler
The directional coupler couples forward/reverse power to RLDU, and monitors the
antenna VSWR.

3.5.3 External Interfaces

The CDU is a module shared by the transmit and receive paths of the BTS. Therefore,
it has interfaces with other modules both in the transmitting and in the 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:
RF signals between CDU combiner input ports and BHPA output ports. They are
transferred through the blind mate connectors on the backside.
BTS receiving signals output from the duplexer. They are sent to RLDU via the
blind mate connector on the backside.
BTS transmitting signals, which are transferred to the cabinet-bottom antenna
interface through the RF cable connected with the N-connector at the front side of
CDU.
BTS receiving signals, which are transferred from the cabinet-bottom antenna
interface through the RF cable connected with the N-connector on the front side of
CDU.
Chapter 3 Radio Frequency Subsystem
3-11
System Principle