External Interfaces; Indices - Huawei Airbridge BTS3612A-1900 Technical Manual

Technical Manual
Airbridge BTS3612A CDMA Base Station
I. Low-pass filter
The low-pass filter is used to suppress the high-order harmonic wave. The low-pass
filter on receive channel also functions to suppress the interference from the transmit
channel.
II. Duplexer
The duplexer is used to isolate both transmitting and receiving signals, suppress
spurious emission and save antennae.
III. Directional coupler
The bi-directional coupler couples forward and reverse power for RLDU, and monitors
the antenna VSWR.
IV. DC supply unit for TMA (BIAS T)
If the BTS is applied to 1900MHz band, a TMA may be used. The BIAS T of the DDU is
to combine and divide RF signals and DC feed so as to provide the TMA with DC.

3.7.3 External Interfaces

The DDU is a module shared by both the transmitting and receiving paths of the BTS. It
provides interfaces with other modules both in the transmitting and receiving paths. Its
external interfaces include a set of 8W8 DB combination blind mate connectors on the
back, and a set of N-connectors and the SMA connectors in the front. The interface
signals include:
Signals between transmit input port and the BHPA interface. They are transmitted
through the blind mate connectors on the back.
Transmitting signals, which are transmitted to the cabinet-bottom antenna port
through the RF cable connected with the N-connector in front of the DDU.
Receiving input signals, which are transmitted from the cabinet-bottom antenna
port through the RF cable connected with the N-connector in front of the DDU.
Signals output from the receive filter. They are sent to the RLDU via the blind mate
connector on the back.
Transmitting forward and reverse coupled RF signals, which are sent to the RLDU
via the blind mate connector on the back.
Transmitting and receiving coupled test signals, which are outputted through the
standard SMA connector in front of the DDU.

3.7.4 Indices

Supported band: 800MHz, and 1900MHz
Chapter 3 Radio Frequency Subsystem
3-15
System Principle