User Manual
Airbridge cBTS3612 CDMA Base Station
System Description
2 Hardware Architecture
2-31
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Temperature sensor
There are 6 temperature sensors for the 6 BHPA slots, used for sensing the air
temperature at each BHPA air outlet. They will convert the information into current
and send to BFMM on BHPA for processing. In this way, fan speed is controlled in
real time.
DB9 connector
RLDU alarm signal
24W7DB
connector
Temperature sensor
Temperature sensor
2mmA/N
connector
RS485
RS485
RS485
RS485
Functional group 1
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Figure 2-16
Functional blocks of BTBM
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Index
Board size: L
%
W
%
T= 664mm
%
262mm
%
3mm
2.3.5 Combining Duplexer Unit (CDU)
I. Overview
CDU mainly has the following functions:
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Combine two carrier signals from the two BHPAs into one signal.
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Isolation and filtering of receiving and transmitting signals.
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Filtering of transmitting signals so as to suppress BTS spurious emissions.
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Filtering of receiving signals so as to suppress the interference from outside the
receive band.
Key internal parts of CDU include isolator, 2-in-1 combiner, duplexer, and directional
coupler.
II. Structure and principle
CDU structure is as shown in Figure 2-17.