Thales NSS 100S-1 Component Maintenance Manual With Illustrated Parts List page 37

B. General RPU Operation (see Figure 4)
(1) Composition
The Receiver Processor Unit RPU comprises the following interchangeable
subassemblies:
(a) Power supply PCB, Z1 which supplies the voltages required for
(b) Filter PCB Z2 which provides:
(c) Central Processing Unit (CPU) PCB Z3, which provides the following
COPYRIGHT SEXTANT Avionique 1995
c
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COMPONENT MAINTENANCE MANUAL
operating the various subassemblies as well as the monitoring and
power-on signals.
A DC/DC converter gavalanically isolates the voltages generated from
the +28VAVION aircraft mains.
The power supply PCB takes two 3.5 V batteries BT1 and BT2 that are
used to provide a backed-up voltage of +5V, which means that while
the RPU is stopped, it is possible to:
- Maintain the time,
- Supply power to the protected memory (Z3 PCB).
- Protection against power surges and filtering of the +28VAVION
supply,
- Filtering of all the input/output information available on connec-
tor J1.
functions:
- Processing of signals transmitted by satellites on eight indepen-
dent receive channels, namely,
. tracking of satellite signals,
. parallel acquisition of satellite signals,
. generation and checking of satellite codes,
. code signal correlations,
- Programmed signal processing,
- Interlocked control of aircraft loops and codes of the eight chan-
nels, satellite message extraction,
- Measuring pseudo-distances and pseudo speeds,
C17004
34-57-96
Page 15
MAY 30/95