P300H
P300 Series Modem Installation and Operating Handbook
Page 75
If a Paradise BUC & FSK are fitted, but the modem / BUC are set in independent mode, then a third
screen is displayed (similar to the 1st) from which the setting of the BUC attenuator may also be
accessed by pressing the down key from the power level menu.
6.6.16 Change, Tx/Rx, Modulator, SPECTRUM INVERT Menu
Spectrum Invert [?]
1=Normal 2=Invert
Change, Tx/Rx, Spectrum Invert Menu
This menu allows the Tx Spectrum to be inverted, to cope with satellites or frequency conversion
equipment which also inverts the spectrum. Note that
apart from the fact that the modem will not
lock onto an inverted spectrum
, on a spectrum analyser the carrier is to all appearances unchanged.
The operator is warned if
ÍÐÛÝÌÎËÓ ×ÒÊÛÎÌ
is active when
ÍÛÌËÐóÝØÛÝÕ
is requested.
NOTE ON BPSK SPECTRUM INVERSION
True spectrum inversion does not affect BPSK signals and so in BPSK mode there is no requirement for
a true spectrum invert feature. Instead in BPSK mode (to be compatible with other manufacturers
equipment), the Tx Spectrum Invert option reverses the ordering of the pairs of Tx data symbols from the
FEC encoder to the modulator. The `Normal` option is compatible with other manufacturers BPSK
equipment. The Invert option (ie reverse pairs of Tx symbols) is compatible with earlier Paradise
products such as the P200 (which we consider to have the `correct` symbol pairing !). On the Rx path
the symbol pairing is automatically determined, and so the Rx Spectrum Invert feature has no effect in
BPSK.
If interworking with other manufacturers equipment it is worth reading the notes in the section
Interworking different manufacturers equipment on page 155 which covers primarily scrambling, but
also the requirements for Spectrum Invert with Viterbi/Sequential in BPSK and QPSK.
6.6.17 Change, Tx, Modulator, AUPC (Software >=V2.12)
This menu is only displayed if the AUPC feature is available. It is advisable to refer to the introduction to
AUPC in section 8.11 on page 156 before enabling this facility.
AUPC: 1:Mode 2:Max 3:Min 4:Slew rate
5:Target Eb/No 6:Tolerence 7:Loss act'
Change, Tx, Modulator, AUPC Menu
Note that options 2 through 7 only display when the AUPC mode It is set to other than
Ѻº
or
Ó±²·¬±®
Ü·-¬¿²¬
, so initially only AUPC: 1:Mode may be displayed.