User's Manual

RF Power Amplifiers
Andrew Corporation – Power Amplifier Group
Propriety – Use pursuant to Company Instruction
Page 3 of 3
6) Tri-Color LED – Single LED that illuminates in green, amber, or red depending on operating
condition. This interface is located on the front panel.
DMAU Circuit Board/Module Functional Descriptions
DMAU contains three individual printed circuit boards and two sub-circuit modules. The main transmit
path flows through all three circuit boards. A description of these boards and their functions follows.
1) Power Supply Board (RF500501):
The power supply board contains the power converter module and other DC-DC converter
circuits needed to convert in-coming 26Vdc to 28Vdc, 7.0Vdc, and 3.3Vdc for use by the
internal DMAU circuits. Inrush current limiting circuits, input and output filtering circuits, and
fuse protection circuits are also included on the PSB.
2) Power Converter Module (RF500480):
Converter module used to convert the incoming +26VDC input which is allowed to vary over
some limited range and produce a steady, regulated +28VDC output for use by the other DMAU
circuits. This module is assembled onto the Power Supply Board.
3) Signal Processing Board (RF500512
):
This board contains the main digital control micro-processor which runs the software needed to
control and monitor various DMAU hardware functions. The micro-processor also allows
communication with the DMAU is enabled through a RS232 communication port on the front
panel. The SPB also holds the Digital-to-Analog Converter (DAC), which creates the analog
output which is then amplified through the RF Amplifier Board.
4) RF Amplifier Board (RF500475)
:
The RF Amplifier Board raises the level of the SPB signal to the rated DMAU output power
through a chain of gain stages. A circulator(off board) is included at the end of the transmit path
to protect the RF power stages from reverse power flow.
5) Amplifier Module(RF500475)
:
The Amplifier Module is an impedance matched RF power transistor used multiple times in the
Amplifier board to attain the rated RF power of 60W at the output of the DMAU.