Andrew Wireless Innovations Group MRB-LMR User Manual
2. System Description
MR Booster Manual (MN001808-1, 9/99)
Page 9
2.4
System Components
2.4.1
Power Supply
The MR Booster provides two high-efficiency power supplies with 26 VDC
and 12 VDC outputs (see Figures 2-4 and 2-5). The 26 V output is split
evenly between the system PAs to provide soft-fail redundancy. The 12 V
output is diode-connected at the controller and the LNAs, ensuring that both
will function if a power supply fails. The power supply has thermal
shutdown capability.
and 12 VDC outputs (see Figures 2-4 and 2-5). The 26 V output is split
evenly between the system PAs to provide soft-fail redundancy. The 12 V
output is diode-connected at the controller and the LNAs, ensuring that both
will function if a power supply fails. The power supply has thermal
shutdown capability.
The AC supply input is auto-ranging to handle 115 and 220 volt, 50 or 60 Hz
systems. During loss of AC mains, the booster will automatically switch over
to the DC input for operation with a BBU.
systems. During loss of AC mains, the booster will automatically switch over
to the DC input for operation with a BBU.
2.4.2
Downlink Power Amplifier
The downlink power amplifiers (see Figure 2-4) provide low distortion
amplification of downlink RF signals using proprietary feedforward
correction techniques. After duplexer, splitter and combiner losses, the PAs
provide 20 dB nominal gain for the booster in the downlink signal path.
amplification of downlink RF signals using proprietary feedforward
correction techniques. After duplexer, splitter and combiner losses, the PAs
provide 20 dB nominal gain for the booster in the downlink signal path.
The amplifiers are powered by the 26 VDC output of the power supplies. To
provide maximum output power and soft-fail redundancy, the downlink power is
shared between either four (high-power option) or two (medium-power option)
PAs. Each PA provides output power and temperature status information to the
system controller and provides both overcurrent and overtemperature protection
circuitry.
provide maximum output power and soft-fail redundancy, the downlink power is
shared between either four (high-power option) or two (medium-power option)
PAs. Each PA provides output power and temperature status information to the
system controller and provides both overcurrent and overtemperature protection
circuitry.
2.4.3
Logic Controller Board
The logic controller board (see Figure 2-4) monitors and controls internal
booster functions, and provides alarms to the donor system. The controller
contains an I
booster functions, and provides alarms to the donor system. The controller
contains an I
2
C bus interface for remote control by a Mikom MR series
repeater. The controller is powered by the 12 VDC supply.
System configuration information is retained in an on-board EEPROM. For
installation or troubleshooting, the board-resident software can be accessed
from an MR repeater, or from an on-site laptop computer. The controller can
set:
installation or troubleshooting, the board-resident software can be accessed
from an MR repeater, or from an on-site laptop computer. The controller can
set:
•
uplink gain
•
PA key/unkey
•
fan speed control (high/low/off)