Dual Duplexer Unit (Ddu) - Huawei Airbridge cBTS3612-1900 User Manual

User Manual
Airbridge cBTS3612 CDMA Base Station
BTS transmitting signals, which are transferred to the cabinet-top antenna
l
interface through the RF cable connected with the N-connector at the front side
of the module.
BTS receiving signals, which are transferred from the cabinet-top antenna
l
interface to DFU for filtering through the RF cable connected with the
N-connector on the front side of the module.
BTS receiving signals output from the duplexer and diversity receive filter. They
l
are sent to RLDU via the blind mate connector on the backside.
Forward/reverse coupled RF signals, which are sent to RLDU via the blind
l
mate connectors on the backside.
Forward/reverse coupled test signals, which are outputted through the standard
l
SMA connector on the front side.
IV. Index
Supported frequency band: 450MHz band
l
Module size: L%W%H=450mm%100mm%344.8mm
l

2.3.7 Dual Duplexer Unit (DDU)

I. Overview
DDU completes the following functions:
Isolation and low-pass filtering of two receiving and transmitting signals.
l
Providing two DC feeds to T-type tower-top amplifier.
l
Voltage Standing Wave Ratio (VSWR) test on transmit channels in both
l
forward and backward directions.
Coupling test of transmitting and receiving signals.
l
Key components within DDU include Bias-T DC feed connector, low-pass filter,
duplexer, and bi-directional coupler.
II. Structure and principle
DDU structure is shown in Figure 2-19.
2-35
System Description
2 Hardware Architecture