I think it's about 1 kHz every 17 carriers. The telephone only has about 4 kHz to work with, so 1.5 kHz or so per direction. You'd probably have to increase the size of the constellation, say 8PSK instead of 4PSK.
Probably a full duplex 32 QAM design (1 carrier per direction), without the equalization training. Way over my head though... _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
