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P300H P300 Series Modem Installation and Operating Handbook Page 116
Monitor: 1:Demod performance 2:Terrestrial BER
3:Carrier ID’s 4:Distant Eb/No & BER 5:AUPC 6:BUC
Monitor Menu
Eb/No:10.3dB, To FEC:6.8E-4, To RS:7.8E-7
FAW BER:<1.0E-12, Final BER:<1.0E-12 (RS)
Monitor, Demod Performance Menu
Terr: 1:BER at Drop Mux =1.6E-8 (FAW)
2:BER at Insert Mux=1.5E-8 (CRC)
Monitor, Terrestrial BER Menu
6.13 MONITOR MENU
Each of these options is now discussed in turn.
6.13.1 Monitor, DEMOD PERFORMANCE Menu
This screen which is regularly updated provides the following information:
Demod Eb/No This is the effective `signal to noise ratio` the USER sees, (ie Ebi/No, the energy
per information bit). This is also shown on several of the Status screens.
To FEC This is the measured uncorrected BER before any FEC. It is the raw uncorrected
bit error rate into the FEC and it is not representative of the “User BER” after
forward error correction. Displayed only if the inner FEC is active, ie not operating
uncoded.
To RS This is the measured error rate into the Reed-Solomon decoder (from the FEC,
unless operating uncoded). The difference between this and the To FEC figure
shows the improvement due to the Inner FEC.
BER on FAW An estimate of the USER BER 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. This is equivalent to the
final user BER. The difference between this and the To RS figure shows the
improvement due to the outer RS FEC.
Final BER This is the final BER figure the modem is using, the source is displayed in
brackets after the BER, in this case (RS). It is based on this figure that the
deferred alarm is raised if it exceeds the user BER threshold.
6.13.2 Monitor, TERRESTRIAL BER Menu
This screen is only available if the signal on the terrestrial ports is framed (ie T1/E1 PCM bearer) which
allows the modem to determine the BER on those ports.
It displays the terrestrial BER at the input to the Drop and Insert multiplexers, these will be the same unless
an interface card with separate Drop/Insert bearers is in use. The display shows BER (source), and the
source may be changed by pressing 1 or 2. The dialogue is exactly the same as described in section 6.10.4
on page 103