UHF Analog Driver/Transmitter/
Chapter 2, System Description,
Translator
Maintenance & Remote Control Connections
LX Series, Rev. 3
2-12
2.1.6.1 (A6) Driver Amplifier Module
Assembly {1303771(1kW) or
1303874(2kW)}; Appendix B)
NOTE:
The (A6) Driver Amplifier Module
Assembly {1303771(1kW) or
1303874(2kW)} replaces the Power
Amplifier Module Assembly (1303770)
when the amplifier module is used as a
driver for any external PA assemblies.
The (A6) Power Amplifier Module
Assembly is made up of a Coupler Board
Assembly (1227-1316), an Amplifier
Control Board (1303682 or 1301962), a
1 Watt Module Assembly (1302891) and
a 40W UHF Module (1304490).
The Driver Power Amplifier Module
contains Broadband LDMOS amplifiers
that cover the entire UHF band with no
tuning required. They amplify the RF to
the power level, 7 Watts Peak of Sync is
maximum, that is needed to drive the
external amplifiers to the output power
level of the transmitter. The Driver
Power Amplifier is used to amplify the
RF output of the Upconverter module. A
cable, located on the rear chassis,
connects the RF output from the
LO/Upconverter at J23 to J24 the RF
input to the driver PA Assembly. This
module contains RF monitoring circuitry
for both an analog and a digital system.
Control and monitoring lines to the
Driver Power Amplifier module are
routed through the floating blind-mate
connector of the Control &
Monitoring/Power Supply module.
The Driver Power Amplifier module and
any External Amplifier modules contain
the same control and monitoring board.
This board monitors RF output power,
RF reflected power, the current draw of
amplifier 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 adjustment potentiometers are
used to calibrate the following:
Power Amplifier Calibration Adjustments
in Analog Systems
R201 Reflected Power Cal
R202 Visual/Forward Power Cal
R203 Aural Power Cal
R204 Visual Offset Zero
R205 Aural Null
In analog systems, the Aural power of
an Exciter Driver Power Amplifier and
the Aural power of any external PA
amplifiers will not be reported by the
system Control Monitoring module.
Additionally the Visual power of these
amplifiers, is reported as Forward Power
just like in digital systems. In analog
systems, aural and visual power will only
be reported for the final system RF
output.
In digital systems, the Forward power of
an Exciter Driver Power Amplifier and
the Forward power of any external
amplifiers, are reported by the system
Control Monitoring module.
If the Control Monitoring module is
monitoring a 10-100 Watt Transmitter,
system power is measured in the Power
Amplifier module. 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. In systems of output
