Huawei Airbridge BTS3612A-1900 Technical Manual page 35

Technical Manual
Airbridge BTS3612A CDMA Base Station
amplification
HPAUz
BHPA
Figure 3-3 Functional structure of BHPA module
I. HPAU
The High Power Amplifier Unit (HPAU) consists of two parts: power amplifier and alarm
circuit.
The power amplifier amplifies the RF signals from BTRM. The amplified RF signals are
then sent to CDU or DFU via BTRB.
The alarm circuit monitors the power amplifier status and generates over-temperature
alarm, over-excited alarm and gain decrease alarm signals when necessary. The alarm
signals will be sent to BBFM, where they will be processed and reported to BTRB.
The coupler is used to couple the RF output signals to the sampling port for test
purpose.
The output power of HPAU can be adjusted by controlling the RF output signal of
BTRM.
II. BBFM
The BTS BTRM Fan Monitor (BBFM) processes fan alarm signals and power amplifier
alarm signals, and sends them to BTRM via BTRB, and then BTRM will report them to
upper level. BBFM can adjust the fan speed based on the ambient temperature and the
actual BHPA output power in order to lower the noise of fans.
For the detail of BBFM, see "3.9 BRFM"
Power
Coupler
Alarm signal
Chapter 3 Radio Frequency Subsystem
RF input
Circulator RF output
Sampling
port
Alarm
circuit
+24V
Alarm signal
BBFM
3-7
System Principle
BTRM
CDU
BDCS
BTRM
BTRB