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
