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[Discuss-gnuradio] Re: D-Star with gnuradio?
From: |
Patrick Strasser |
Subject: |
[Discuss-gnuradio] Re: D-Star with gnuradio? |
Date: |
Sun, 09 Jan 2011 04:23:38 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.6) Gecko/20050602 Thunderbird/1.0.2 Mnenhy/0.7.2.0 |
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