New digital voice mode requires just 1.1kHz bandwidth

Jason Buchanan, N1SU, has announced a new digital voice mode based on WinDRM called FDMDV which claims to offer robust digital voice communication with enhanced interference rejection. The new mode requires just 1.1kHz of bandwidth and is claimed to work at signal to noise ratios as low as 3dB. It is based on 15 carriers using the 1400 MELP codec with no FEC. Fourteen 50 baud QPSK carriers with 75Hz spacing surround a central BPSK carrier at twice the power level for auto tuning and frame indication. Higher power in each carrier combined with an occupied 1.1kHz bandwidth provides improved robustness over its WinDRM and DRMDV predecessors. A poster on the WinDRM Google Group noted that audio quality was fair at an SNR lower than DRM versions.

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