PSK31 is a new digital mode:
- designed by Peter G3PLX
- that betters SLOWBPSK, an idea and implementation of Pawel SP9VRC
- based on the RTTY mode of operation,
- useful for live keyboard to keyboard QSO
- that works at 31.25 bauds,
- that uses varicode caracter coding what gives 50wpm,
- easy to use and monitor,
- that give very good copy under low Eb/No numbers and is thus suitable for QRP,
- that instead of using FSK or on/off keying uses BPSK or QPSK with a Viterbi decoder,
- that is available for free for many platforms, including Windows (c) with SoundBlaster type Soundcard,
- and uses advanced DSP and narrow band (31 Hz!!) techniques.
PSK31 is not a digital mode that
- will make Pactor, Pactor-2, Clover-II or Gtor obsolete,
- offers error free links,
- can be used to transmit files or acces mailboxes...
You can see also how much spectra they use.
These images have been obtained with EvmSpec.
You can hear these modes here: Note that these files will be correctly decoded if feeded on the DSP board or SoundBlaster, that's why they are so lengthy.Note the preamble at the start and end of the transmission. If you only want to know how they sound, you can get the ADPCM compressed version (I haven't tested if they decode correctly).
A basic approach to understand and design a PSK31 modem is here, by Peter G3PLX. See also articles section
- PSK31 in bpsk mode calling CQ. Compressed here.
- PSK31 in qpsk mode calling CQ. Compressed here.