Technical Manual
Airbridge BTS3612A CDMA Base Station
Module dimensions: 450mm%100mm%344.8mm (Length%Width%Depth)
3.8 RLDU
3.8.1 Overview
The Receive LNA Distribution Unit (RLDU) consists of Low Noise Amplifier (LNA),
distribution unit, configuration switch and alarm monitoring circuit. Its main functions
are:
Low noise amplification and distribution for BTS main/diversity receiving signals.
Built-in electronic RF switch supporting multiple BTS configurations (3 sectors or 6
sectors).
Antenna VSWR monitoring and alarming, BTS forward RF power detecting, LNA
running status monitoring and alarming.
3.8.2 Structure and Principle
The RLDU structure is shown in Figure 3-8.
RXAM-TEST
RXBM-TEST
DC-IN
PWR
S/W
DB15
Figure 3-8 Structure of RLDU
Switch distribution
LNA
module
module
Power supply
VSWR check processing
Forward power output
3-16
Chapter 3 Radio Frequency Subsystem
VSWR and power
check
System Principle
RXBD-IN
RXBM-IN
RXAD-IN
RXAM-IN
APf-IN
APr-IN
BPf-IN
BPr-IN
RXAM1
RXAM2
RXAD1
RXAD2
RXAM3/RXBM1
RXAM4/RXBM2
RXAD3/RXBD1
RXAD4/RXBD2