> > Are any minimum SNR numbers of those 2 modes known (375/300 bps)? > The SNR for 8FSK can be about -5dB. > The SNR for 8PSK at 75baud is about -10dB. > Sorry, I don't remember the typical SNR for 300 or 600 baud 8PSK.
I think we must start to specify "SNR at Bandwidth", otherwise the numbers dont match well. Im no expert in the field... > A non-standard type of OFDM could be designed for this slow DV, with > only 2 amplitude levels, to achieve more robustness. I estimate -2dB > SNR to 1dB SNR is easily possible, and probably much better. The drmdv ofdm is 1 amplitude level, 4 phase levels already. Going to only 2 phase levels could bring down the minimum snr to around +2db (at 600bps). That is at 2.4khz BW of signal, 2.7khz BW of snr measurement.
