Wow, G4GUO is great ham operator Charles Brain. May be he is here in this mailing list, I don't know.
Best regards, Rafael Diniz > schrieb Rafael Diniz on 2011-01-09 03:56: > > Hi Patrick, > > Thanks for the answer. > > I know about codec2, but how about what modulation to use? > > I read about the AOR ARD9000MK2[1] modem, that uses the: > > "G4GUO open protocol". > > Do you know if is possible to implement this OFDM based one? > > Unfortunately I could not find any document that describes the G4GUO > protocol. Would be very interested too. > > From http://www.aorusa.com/ard9800.html I got: > > Modulation method: OFDM > Band width: 300 Hz - 2500 Hz, 36 carriers > Symbol Rate: 20 mS (50 baud) > Guard interval: 4mS > Tone steps: 62.5 Hz > Modulation method: 36 carriers: DQPSK (3.6K) > AFC: +/- 125 Hz > Error correction: Voice: Golay + Hamming > Video/Data: Covolution + Reed-Solomon > Header: 1 Sec. 3 tones + BPSK training pattern for synchronization > Digital voice: AMBE2020 coder, decoder > Signal detection: Automatic Digital detect, Automatic switching > between analog mode and digital mode > Video Compression: AOR original adaptive JPEGFrom > > Seems not too far off to implement in Gnu Radio/USRP. > > Patrick > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- R�dio Muda, radiolivre.org, TV Piolho, tvlivre.org Chave PGP: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x2FF86098 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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