User Manual

LX Series Power Am plifier Assem bly Chapt er 2, Am plifier Assem bly Descript ion
& Rem ot e Cont rol Connect ions
LX Series, Rev. 0 2- 2
to J200 the RF input to the PA Assem bly.
This m odule contains RF m onitoring
circuitry for both an analog and a digital
system . Control and m onitoring lines to
the Power Amplifier m odule are routed
through the floating blind- m ate
connector of the Control &
Monitoring/ Power Supply m odule.
The 100 Watt Translator/ Exciter Driver
Power Am plifier m odule and any
External Am plifier m odules contain the
same control and m onitoring board.
This board m onitors RF output power,
RF reflected power, the current draw of
am plifier sections, the supply voltage,
and the temperature of the PA heat sink.
The RF power detector circuit outputs
vary with operating frequency. These
circuits must be calibrated at their
intended operating frequency. Front
panel adjustm ent potentiom eters are
used to calibrate the following:
Table 1: Power Amplifier Calibration
Adjustm ents in Analog System s
R201 Reflected Power Cal
R202 Forward Power Cal
R204 Meter Offset Zero
In analog system s, the Aural power of
an Exciter Driver Power Am plifier and
the Aural power of any external
am plifier will not be reported by the
system Control Monitoring m odule.
Additionally the Visual power of these
am plifiers, is reported as Forward Power
just like in digital system s. I n analog
system s, aural and visual power will only
be reported for the final system RF
output.
In digital system s, the Forward power of
an Exciter Driver Power Am plifier and
the Forward power of any external
am plifier, is reported by the system
Control Monitoring module.
If the Control Monitoring m odule is
monitoring a 5- 50 Watt Digital or 10-
100 Watt Analog Translator, system
power is m easured in the Power
Am plifier m odule. The wired
connections are transferred through the
power supply connector to the
backplane board on a five position
header. All four positions of control
board switch SW1 must be set on to
route these lines as the system 's RF
power signals. I n systems of output
power greater than 50 Watts digital or
100 Watts aural, system power is
monitored by an external m odule that is
connected to TB31 and control board
SW1 switches m ust be set off.
The Forward Power of the
Translator/ Exciter Driver Power Amplifier
module is routed to the Upconverter
module as AGC # 1. A system over-
drive condition is detected when this
value rises above 0.9 VDC. When an
over- drive condition is detected, the
Upconverter m odule reduces its RF
output level. For values less than 0.9
VDC, the Upconverter uses this voltage
for autom atic gain.