The demod-remod technique for demodulating co-channel FSK signals

The authors describe the demod-remod method of demodulating two cochannel MEFSK (Manchester-encoded frequency shift keying) signals. The technique uses a conventional demodulator to obtain an estimate of the primary data sequence. The primary data are then remodulated and subtracted from the received signal to obtain an estimate of the secondary signal. The secondary signal is demodulated using conventional demodulation techniques. The authors present a description of phase noise, its effect on demod-remod performance, and methods used to mitigate it. Experimental results showing the range of signal power separations and carrier-to-noise ratios over which the demod-remod technique works are also presented