P300H
P300 Series Modem Installation and Operating Handbook
Page 160
. M&C messages will of course take
S or IDR overheads) then it
'
s worth
, by having enough bandwidth so that the maximum 33% it uses in
Sta
wor
not correctly configured. If it does not work in this mode don
'
t start
ô Ê·»© ݱ²º·¹ô ̨ô ø¼±©²ô ¼±©² »¬½÷
.
tmospheric conditions are
favourable (unlikely).
, set the
Ó¿¨ °±©»®
to the
maximum increase you are allowed, and set
Ó·² °±©»®
to
Zero
. This will prevent the Tx
ing
if the Eb/No is better than the target, but will increase the power if the
Set the
̱´»®¿²½» É·²¼±©
size to something practical, say 0.2 to 0.5dB (depending on how
in the Eb/No).
setting is
Ó¿¨·³«³
, but note that anything, which interrupts the link, will cause the Tx carrier to
ally log the parameters:
Use the Autolog feature to optionally record the distant Eb/No and/or the AUPC delta power.
This may prove useful in determining how often the AUPC is required, and if it manages to
messages whilst interleaving the AUPC data
longer to get across a 2400 Baud ESC than a 9600 Baud ESC, but if the bandwidth
has to be paid for (ie it s not withing the IBS/SM
the saving.
Alternatively if the station M&C is at say 2400 Baud, but the station is transmitting a
512kbps IBS/SMS link that would support a 19200 Baud ESC within the IBS/SMS
overhead. Setting the ESC for 19200 Baud will provide a very high update rate for the
Eb/No monitoring
this mode can provide at least a 1Hz update rate.
rt the AUPC in a passive mode (distant end monitoring only mode) to ensure the system is
king:
Switch on REMOTE REPORTING (
ݸ¿²¹»ô Ψô Ü»³±¼ô ßËÐÝ
) to respond to the Eb/No
requests at the
distant modem
.
Set the local AUPC for
Ó±² Ü·-¬
, to determine if it is working correctly. If it is then the distant
Eb/No should be available on the
Ó±²·¬±®ô Ü·-¬¿²¬
screens. If the Eb/No or BER figures say
Unavail then the ESC is
changing the AUPC, sort out the ESC channel!
When the distant Eb/No is displayed, record the distant Eb/No under clear sky conditions.
Then change the AUPC mode to
Maint Eb/No
in order to get access to the other AUPC
settings.
Review the proportion of ESC bandwidth and more importantly the distant Eb/No update rate
using
ײº±
Determine the parameters for the AUPC:
Determine the way the AUPC will operate, will it try to:
1.
Maintain a minimum Eb/No
, but take advantage of a better Eb/No when
atmospheric conditions are favourable (normal)
2.
Maintain a fixed Eb/No
, reducing Tx power when a
To maintain a minimum Eb/No
, set this as the
Ì¿®¹»¬ Û¾ñÒ±
power
decreas
Eb/No falls below target.
To maintain a fixed Eb/No
set this as the
Ì¿®¹»¬ Û¾ñÒ±
, set the
Ó¿¨ °±©»®
to the
maximum increase you are allowed, and set
Ó·² °±©»®
to the limit of the power decrease
you will accept. The Tx power will increase and decrease within the limits to try and maintain
a constant Eb/No.
accurately you wish to try and mainta
Set the
Í´»© כּ
to something which can respond to a fast fade. We suggest no less than
15dB/min (ie 0.25dB/sec) If there is no reason to set a particular slew rate then leave it set to
zero (no slew rate limit).
Set the
ݱ³³- Ô±-- ß½¬·±²
after careful consideration. The most advantageous
increase to the maximum delta Tx power.
Ú®»»¦»
is probably the most sensible choice,
causing the carrier to remain at the current value until the link is restored. Finally
Ò±³·²¿´
is
the safest option, with the AUPC returning the carrier to it s nominal power if the link is
broken.
Option
