Indices; Cdu; Overview; Structure And Principle - Huawei Airbridge BTS3612A-1900 Technical Manual

Technical Manual
Airbridge BTS3612A CDMA Base Station

3.4.4 Indices

Dimensions: 664mm%262mm%3mm (Length % Width % Depth)

3.5 CDU

3.5.1 Overview

The Combining Duplexer Unit (CDU) accomplishes the following functions:
Combining two carrier signals from the two BHPAs into one.
Isolating and filtering the receiving and transmitting signals.
Filtering the transmitting signals so as to suppress BTS spurious emissions.
Filtering the 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, filter and
directional coupler.

3.5.2 Structure and Principle

CDU structure is as shown in Figure 3-5.
D
Pr-OUT
D
Pf-OUT
D
TX1
D
TX2
D
RXM-OUT
RXD-OUT D
LPF: Low Pass Filter
Figure 3-5 Structure of CDU
FILTER COMB.
ISOLATOR
LPF
LPF
LPF
D-SUB N-Type
D N
Chapter 3 Radio Frequency Subsystem
DUPLEXER
COUPLER
BPF
S SMA-Type
BPF: Band Pass Filter
3-10
System Principle
TX-TEST
S
TX/RXM-ANT
N
S RXM-TEST
S RXD-TEST
N RXD-ANT