Download W4100D User Manual

OPERATING MOCES PAGE 74
Frequency range
System
Baudrate
Modulation
Receiver setting
Signal sources
HF-MODES
FEC
164.48 or 218.3 Baud
SSB or DIRECT-FSK
CW, LSB or USB
AF or IF
RUM-FEC
Analysis
164.48 Baud
Nor. Polarity
Auto
218.30 Baud
ECC ison
RUM-FEC operates at speeds of
164.5 and 218.3 Baud on the
radio link.
The HNG-FEC and RUM-FEC modes
are technically very similar.
RUM-FEC alphabet has a codeword length of 16 bits where
each of the 32 used bit combinations corresponds to an
ITA-2 character.
The RUM-FEC alphabet is designed to obtain a maximum
Hamming distance for error
detection. The actual ITA-2
alphabet is not contained in
the code table. Error correction is done , like in the
case of HNG -FEC, by table
look-up of the bit pattern
(character)
closest
resembling the character in error.
Demodulator
Options
96.0 Baud Var
Force LTRS-FIGS
ITA-2
RUM-FEC has a bit spread of
128 bits , each new character
starting at intervals of 16
bits. The software synchronises to traffic as well as
to idle bit patterns.
Bit inversion is often used.
The bit inversion pattern may
be selected from the ”Bit inversion” field.
Error correction may be enabled or disabled using the
”ECC is on/off” field.
In RUM-FEC mode the signal
polarity (sideband) can be
manually selected by clicking
on the ”Nor. Polarity/Inv.
Polarity” field. If polarity
changes during a transmission,
synchronisation
will
not be lost.