README 979 B

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  1. FreeDV is a Digital Voice mode for HF radio.
  2. You can run FreeDV using a free GUI application for Windows, Linux and
  3. OSX that allows any SSB radio to be used for low bit rate digital
  4. voice. Alternatively you can buy a SM1000 FreeDV adaptor that allows you
  5. to run FreeDV on any HF radio without a PC or sound card.
  6. Speech is compressed down to 700-1600 bit/s then modulated onto a
  7. .25 kHz wide signal comprised of 16 QPSK carriers which is sent to the
  8. Mic input of a SSB radio. The signal is received by an SSB radio, then
  9. demodulated and decoded by FreeDV. FreeDV 700C is approaching SSB in
  10. its low SNR performance. At high SNRs FreeDV 1600 sounds like FM,
  11. with no annoying analog HF radio noise.
  12. FreeDV was built by an international team of Radio Amateurs working
  13. together on coding, design, user interface and testing.
  14. FreeDV is open source software, released under the GNU Public License
  15. version 2.1. The modems and Codec 2 speech codec used in FreeDV are
  16. also open source.