SYSTEM DESCRIPTION AND INSTALLATION MANUAL
HS--700 High Speed Data System
23--20--33
30 Aug 2002
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Page 1--7
I.
BITE
(1) General
(a) The HSU has two types of BITE: continuous monitoring (CM) and PAST/POST. If
a BITE error occurs, the BITE error code number is reported to the SDU and the
fail/pass light emitting diode (LED) illuminates red.
(b) The CDM has no BITE functions performed by itself. The HSU performs the BITE
tests on the CDM by checking CRC, etc. If a BITE error occurs in the CDM, the
BITE error code number is reported to the SDU and the fail/pass LED on the
HSU illuminates red.
(2) POST
(a) The HSU can report some errors during POST, but these errors do not prevent
the SDU from operating properly. The SDU and HSU take appropriate actions on
the detected BITE errors. Some of the more drastic actions from the SDU could
be to turn the HSU RF off and reset and keep the HSU reset.
(3) PAST
(a) The PAST can be activated either through the SDU control interface or the reset
button on the front panel of the HSU. The PAST performs the same tests as the
POST.
(4) CM
(a) Some of the hardware in the HSU is under continuous supervision by the BITE
software or by dedicated BITE monitoring hardware (for burst duration
monitoring). If any errors are detected either by software or hardware, they are
reported to the SDU and appropriate actions are taken.
(5) Performed Tests
(a) Each error code is categorized into either an error or warning. Errors are errors
that prevent the full use of all the HSU functionalities. Warnings are errors that do
not prevent the use of the HSU but require the HSU to be sent for repair. The
tests include:
•
Digital hardware integrity tests
•
Software integrity tests
•
RF hardware monitoring.
J. Cable Loss
(1) The RF cable loss specifications for the RX and TX coax cables are per ARINC 741.
ARINC 741 specifies an allowable input power level to the HPA of --12 to --2 dBm,
given a variation in SDU to HPA cable loss of 19 to 25 dB (including a possible
external combiner for multiple antenna configurations). For each installation, the
specific RX and TX cable loss must be entered into the CDM through the CMT
interface for the HSU to be able to compensate its RX and TX gain accordingly.