User's Manual

Selex ES S.p.A.
Information contained in this document may not be used, applied or reproduced for any purpose unless agreed
by Selex ES S.p.A. in writing
60
8.1.8 Power Amplifier module – PA
The “Power Amplifier” (PA) module is a wide band RF amplifier in UHF
frequency band: 896 ÷ 941 MHz.
Their time of TX ramp up/down is less than 1200 μsec. This makes the module
compatible with the stringent demands of digital transmission.
Thanks to a microprocessor mounted on board, the module is able to implement
the PUFF technology (Powerful Universal Forming Function) for the shaping of
transient power in order to obtain compliance with the rapid transient rules of
ACP (Adjacent Channel Power).
The microprocessor also manages completely the operation of the module: this
would remove any calibration procedures. All configuration changes are performed via software.
Other main functionalities are:
 continuous transmitter’s operations (100% duty cycle).
 Output power selectable between two values (Phi and Plo), each of which can be SW set to
a nominal value between 10 and 110 Watts.
 final stage protected against excessive mismatching output power. In the case that VSWR
remains above a set threshold (eg ReturnLoss = 5dB) for more than a fixed time, the
module is able to send an alert and the output power will not exceed a safety value (eg ≤
10watt).
 temperature threshold alarm: if the temperature remains above a set value for more than a
fixed time, the module is able to send an alert and will ensure that the RF output power will
not exceed a predetermined safe value.
The front panel is provided with bi-color leds to help in troubleshooting the system. The table below
describes the meaning of the leds:
LED
Color
Label
Description
1
Green
PWR High
High Power level selected and correctly On Air
Red
PWR fail
Emitted power less than a FW configured threshold (3 dB
typical)
2
Green
PWR low
Low Power level selected and correctly On Air
Red
VSWR
On Air and VSWR level is greater than FW configured
threshold
3
Green
Control bus busy
Activity on the control bus