External Interfaces - Huawei Airbridge BTS3612A-1900 Technical Manual

Technical Manual
Airbridge BTS3612A CDMA Base Station
control are performed, so as to ensure the RF signals output meet the protocol
requirements on power level, Adjacent Channel Power Radio (ACPR) and
spuriousness.
Main/diversity receiver
The main/diversity receiver converts the RF signals output by RLDU to specified
intermediate frequency signals via down-conversion, and performs wave filtering,
signal amplification and power control before/after the down-conversion, so as to
ensure the intermediate frequency signals output can be received by BIFM.
Local oscillator
The local oscillator consists of intermediate frequency source, transmit RF synthesizer
and receive RF synthesizer.
The intermediate frequency source generates the local oscillator signals for
intermediate frequency up conversion in transmit path.
The transmit RF synthesizer generates the local oscillator signals for the up-conversion
of the transmit path.
The receive RF synthesizer generates the local oscillator signals for the down
conversion of main/diversity receive path.

3.2.3 External Interfaces

There are interfaces between the BTRM and the BHPA/RLDU/BRDM/PSU. The
descriptions of each interface are given as below:
RF interface between the BTRM and the BHPA
The RF transmitting signal is output via this interface to BHPA, where the signal is
amplified and then outputted.
RS485 interface between the BTRM and the BHPA
This interface is used to transfer alarm and control signal, and power detection signal.
RF interface between the BTRM and the RLDU
The main/diversity RF receiving signal output by RLDU is received via this interface.
Optical interface between the BTRM and the BRDM
Baseband data are transmitted or received via this interface.
Power supply interface
Interface with BTS3612A TRx Backplane (BTRB), This interface is used to provide
+24V power supply to BTRM.
Chapter 3 Radio Frequency Subsystem
3-5
System Principle