MINI-LINKEandEMicro
4.4.6 RSSI
A portion of the 140 MHz signal is fed to a calibrated detector in the Received
Signal Strength Indicator (RSSI) to provide an accurate receiver input level
measurement. The measured level is accessible either as an analog voltage at
the alignment port or in dBm through the operation and maintenance system.
4.5 Microwave Unit
4.5.1 DC/DC C onver ter
The DC/DC converter provides stable voltages for the RTU.
4.5.2 Control and Supervision Processor
The processor for radio unit control and supervision is situated on the
microwave unit circuit board. Its main functions are described below.
Alarm collection
Alar m and status signals are collected, resulting in summary status signals (A
and B-alar ms). Alar ms are visualized by LEDs on the radio unit.
Command Handling
Commands such as transmitter activation/deactivation, channel frequency
setting, output power setting and RF loop activation/deactivation are executed.
Radio Terminal Control and Message Handling
In addition to the above, the processor controls the radio unit’s internal
processes and loops.
4.5.3 Transmitter Block
Transmitter O scillator (MCM)
The frequency of the transmitter is controlled in a Phase Locked Loop (PLL) (a
sample of the VCO signal is fed to a divider and fur ther on to a programmable
phase detector). An unlocked VCO loop generates a transmitter frequency
alar m.
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AE/LZT 110 2012 R8C 2002-03-04
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