. GENERAL SPECIFICATIONS
Creator: Patrick Lindecker F6CTE (2002/2003)
Description :
Baud : 10 (PSKAM10) , 31.25 (PSKAM31), 50 (PSKAM50)
Speed : 6 wpm (PSKAM10), 20 wpm (PSKAM31), 31 wpm (PSKAM50),
Modulation : DBPSK
Reception mode: indifferent (LSB or USB)
Dictionary : 56 “ fixed length ” characters A..Z 0..9 <CR> <SPACE> . , : - = + ? $ ’ ( ) ! / @ % with an error reset character and an idle character (displayed by ‘>’). Small characters are transformed in capital characters and special characters as “ é ” are transformed in standard capital (in the example: “ E ”)
Shape of pulse : for PSKAM10 and PSKAM50: rectangular but the connection between 2 successive different bits is done by a decreasing sine then by a creasing sine (each of one during quarter of period)
for PSKAM31: raised cosine
Bandwidth : about 50 Hz (PSKAM10), 80 Hz (PSKAM31), 260 Hz (PSKAM50),
Demodulation : coherent,
Synchronization: automatic using the signal
Correction code: no
Convolution code: no
Interleaving : no
Repetition : each character is repeated 5 positions later (so 0.8 s in PSKAM, 1,28 s in PSKAM31 or 4 s in PSKAM10) between 2 transmissions of the same character) (example: A X B Y C A D B…). This diversity in time allows the correction of an erroneous character. Its detection is easy due to the particular content of a character (5 “ space ” and 3 “ mark ”).
Automatic Frequency Correction: from +/-3 Hz to +/- 10 Hz depending on signal level,
Drift tolerance : 60 Hz/mn for PSKAM31 and PSKAM50 and 40 Hz/mn for PSKAM10 (depending on signal level)
Lowest S/N for 2% errors: -11 dB for PSKAM50, -13 dB for PSKAM31 and -19 dB for PSKAM10 (for white noise in a 3 kHz bandwidth)
