Installation Maintenance Manual
FMHPA 82166
2-3
Jul 2008
©
THALES AVIONICS Ltd. This document and any
information included are the property of Thales Avionics.
They cannot be reproduced, disclosed or utilized without the
company’s prior written approval
C. General Operation
The FMHPA is a Linear Power Amplifier for embedded communication system (TFS).
FMHPA supplies up to 35W RF power to the Aircraft Satcom antenna when the physical
separation of the SDU and the antenna is such that the RF loss between the SDU and the
antenna will be greater than that allowed in ARINC 781. Alternatively, the FMHPA may
be used in cases where more power is required than would be available from the HPA
within the SDU, to provide the services offered.
Its function is to amplify the modulated signals supplied by the SDU. The number of
signals to be amplified depends on the communication traffic, from a single up to the
maximum capability of the SDU. FMHPA also includes a constant and programmable
RF gain, a high grade of self test (90% of failures are detected) and a high temperature
protection function.
(1) Functional Modes:
The FMHPA operates in the following five modes:
a.
Nominal Mode (35W output)
Nominal Mode (NM) is defined as the operating condition when power supplies are
applied. This mode is enabled by default at powerup, the power supply is defined at its
nominal Voltage (27V)
b.
Low Power mode (9W output)
Low Power Mode is defined as the operating condition which can be enabled by SDU
(or FMHPA in security case) when the temperature is high and in order to reduce the
dissipated power (for example to save the internal temperature when there is a loss of
cooling). For this mode, the power supply is changed from Nominal Voltage (around
+27V) to Low Voltage (17V). Cockpit only services available.
With NM and LPM modes, the main characteristic of the modes is to maintain a constant
gain whatever the temperature.
c.
Carriers Off/MUTE Mode
This mode switches off the RF gain, and puts the FMHPA in Standby (STBY) mode.
d.
STBY / On mode
With Standby mode, the main characteristic of the mode is to have the lowest
consumption.
In this mode, the RF output power equals zero, and the thermal dissipation within the
FMHPA is reduced to the minimum possible to permit temperature monitoring and
