User Manual
Airbridge cBTS3612 CDMA Base Station
System Description
2 Hardware Architecture
2-34
N
D-SUB
S
D
N-Type
SMA-Type
N
S
S
D
D
D
D
TX-TEST
TX/RXM-ANT
RXM-TEST
Pf-OUT
Pr-OUT
TX
RXM-OUT
Low-pass filter
D
RXD-OUT
N
RXD-ANT
S
RXD-TEST
Diversity receive filter
Low-pass filter
Duplexer
Directional coupler
Figure 2-18
Structure of DFU
l
Low-pass filter
At the transmitting signal input port and main/diversity receiving signal output port,
there are three low-pass filters used for low-pass filtering of transmitting and
main/diversity receiving signals.
l
Duplexer
The duplexer is used to isolate transmitting and receiving signals, suppress
transmission spurious and reduce antenna quantity.
l
Diversity receive filter
The diversity receive filter of DFU is a separate path. Signals received by the
diversity antenna must be filtered by the diversity receive filter in DFU before being
sent to the low-noise amplifier in RLDU for amplification.
l
Directional coupler
The directional coupler couples forward/reverse power for RLDU, and monitors the
antenna VSWR.
III. Interface
DFU is a module shared by transmit and receive path of the BTS. It has interfaces
with other modules in the transmit and receive 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:
l
The signals between DFU and BHPA, which are transferred through the blind
mate connectors on the backside.