EUROTEL - ITALY
ETL0480TBD
•
Should a transistor of one of the RF output stages fail in short circuit, one supply will be shorted out
(the supply will not fail in this condition) and the amplifier output, while dropping, will still be at an
useful level of approximately 25% rated power.
•
Should a transistor of the RF driver stage fail in short circuit, one of the fuses in the driver module
will open, and the amplifier output will drop to approximately 50% rated power.
•
The yellow LINE LED, when lit, shows presence of A.C. power mains.
•
The green ON AIR LED is on when the Amplifier is operating under normal conditions. When the
RF power output drops below approximately half power (- 3 dB threshold), this LED is extinguished.
•
The red ALARM LED is normally dark. It turns on to indicate that one alarm has occurred. In this
condition the Metering, alarm and Protection module immediately disables the amplifier.
•
The red V.S.W.R. ALARM LED is normally dark. It turns on to indicate that the reflected output
power has risen above a pre-set, critical threshold. In this condition the Metering and Protection
module immediately disables the amplifier.
•
The yellow WARNING LED is normally dark. It turns on to indicate that one or more operating
parameters have risen above the normal limiting values. This LED blinks if some past warnings and
alarms are stored in the EEPROM non volatile memory of the microprocessor. This LED turns off
only
RF Drive (A)
Driver
Amp.
Dir.
Coupler
Four way
Hybrid
divider
RF Amp
.
RF
Amp
RF Amp.
Dir.
Coupler
Output
Filter
Logic &
Micro
Four way
Hybrid combiner
RF Amp.
Digital
display
RF Out
EXCITER
Figure 4: ETL0470 RF Amplifier blocks diagram
October 2002
CMAN0480ENG
Page 13
