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P300H P300 Series Modem Installation and Operating Handbook Page 104
Satellite: 1:BER est’ 2:IBS MF period
3:Carrier ID’s 4:Back alm map 5:IF-50/75
Change, User-Opt, Operation, Satellite Menu
6.10.6 Change, User-Opt, Operation, SATELLITE Menu
BER ESTIMATE This selects the source for the USER BER estimate displayed on the Receive
Status Screens, and compared to both the Deferred USER BER alarm, and BER
> 1 x 10 alarm thresholds. The selection is from:
-3
AUTO The unit selects the most appropriate source. Note that the
INTELSAT mandatory method is FAW, although Auto will
select more accurate or more quickly updated methods if
available. The list of priorities is as follows:
1. The PRBS tester (if in the main data channel)
2. The Reed-Solomon outer FEC Codec (if active)
3. The Turbo, Viterbi or Sequential inner FEC (if active)
4. The PRBS tester in ESC or Aux channels (if active)
5. The errors counted over one minute on the FAW (if
framed)
6. No estimate of BER
FAW An estimate based on the count of errors on the Frame
Alignment Words (FAW) received by the deframer over a 1
minute sliding window. Only available if operating in a
framed mode.
FEC An estimate of the output error rate from the FEC decoder,
based on the count of errors into the FEC and the FEC code
rate. Note that if FEC is manually selected, but Reed-
Solomon is active, the BER estimate will not include the
significant error improvement of the RS codec.
RS An estimate of the output error rate of the RS Decoder based on
the number of uncorrectable words passed by the decoder.
PRBS The real BER as measured by the PRBS tester, whether it be in
the ESC or Aux channel, or the main data channel.
Default: AUTO
IBS MF PERIOD This option is only applicable to Custom, IBS, Minimum overhead modes. In this
mode the overhead is varied to accommodate any ESC requirements, and if the
ESC and main data rate are very low the overhead multiframe structure might be
very long. Whenever the Rx carrier is re-acquired the multiframe alignment also
has to be re-acquired, and this option allows the maximum multiframe period to
be specified in order to prevent excessively long multiframe periods affecting
carrier re-acquisition times. By default it is 2000ms, approximately 4 times the
normal IBS multiframe time of 512ms at 64kbps. This will only be an issue where
very low data rates (<16kbps) and low ESC rates are in use, or Minimum
overhead mode is active with No ESC requirement and the multiframe just
provides timeslot ID maintenance and backward alarm facilities. Only consider
adjusting from default if you see long periods where the status displays "TS32
Multiframe sync lost" or "CAS Multiframe sync lost" after the demod has lost and
re-acquired the carrier. Default: 2000ms
Carrier ID'S The earlier versions of the Eutelsat SMS specification defined 3 eight bit identities
which may be transmitted once per satellite TS32 multiframe to identify the carrier
and the earth station. These were named Station ID, Carrier ID & Spare ID. More
recent issues just say "reserved for uses such as.....". This options allows these