CCW-FSK (CW cohérente en FSK)
Traduction anglaise.
This mode is included into the software
MULTIPSK by
Patrick F6CTE, there is the description of
this mode and its variants as well as the specifications coming from his
software :
Click on the copie of the screen in order to
listen to the corresponding audio
signal.
Created by : Patrick Lindecker (F6CTE) in 2005
Description :
This
mode derives from the Multipsk CCW mode. It permits a more efficient
decoding and a better Pmean/Ppeak ratio than in classical CCW (OOK).
The Morse sound can be built digitally, which strongly reduces radio
noise and allows the selection of the only one signal clicked on the
waterfall.
The essential difference is the
transmission of a complementary morse signal, on a carrier situated at
a 240 Hz distance, for example:
* morse signal at 1000 Hz,
* complementary morse signal at 760 Hz.
This "shift" of 240 Hz is sufficient to separate the 2 signals for a human decoding .
The 2 signals form a FSK modulation.
Note:
the program can decode either the 2 carriers in FSK or both carriers in
OOK, or one of the two carriers in OOK, according to the link
conditions. The normal decoding is done in FSK.
All the characteristics are the ones of CCW Multipsk, except the following:
Receive mode : USB only
Pmean/Ppeak : 1
Lowest S/N : -14 dB at 12 wpm, -10.5 dB at 24 wpm and -8 dB at 48 wpm.
Mapping of Morse characters into ANSI characters :
There are not always letters to
represent directly the CW/CCW characters, for example the code
Error signal which is a serie of dots (........).
Therefore, a conventional letter is
associated to display the CW/CCW character. For example, the code Error
signal (........) is displayed as the letter "*" in CW.
Mapping
of CW/CCW characters to ANSI characters received or transmitted
(displayed between brackets) is described in the following:
A ... Z --> <A> à <Z> (small letters translated in capital letters)
é=è=ë --> <é>
0 ... 9 --> <0> à <9>
Ä , à --> <Ä> , <à>
Ñ , "CH" --> <Ñ>(<Alt> 165), <ç>
Ö , Ü --> <Ö> , <Ü>
. , "," , ";" --> <.> , <,> , <;>
: , ? @ --> <:> , <?>, <@>
' , - , = --> <'> , <-> ,<=>
/ , ( , ) --> </> , <(> ,<)>
Underlined --> <_>
Understood --> <&>
Error, +, " --> <*> except in CCW and CCW-FSK, <+>, <">
Waiting --> <£> except in CCW and CCW-FSK
Message start --> <!> except in CCW and CCW-FSK
VA (Message end) --> <$>
Separator --> <%>
Space --> space bar (7 dots duration)
Amateurs use most of all the Morse characters: A..Z 0..9 ? = / . + VA Error
Note.: + and VA are only used at the end of the message.
In CW, a carriage return (line feed) is transformed into space.
In CCW and CCW-FSK, a carriage return (line feed) is transformed into a message start.
In CCW and CCW-FSK, the waiting (idling) character (-_---) is not displayed.
