The demodulated bit stream is then adaptively remodulated and subtracted from the aggregate received signal. Provided the remodulated signal accurately mimics the primary signal component of the received signal, the difference should consist of the weaker secondary FSK signal plus noise. This difference signal is then demodulated using a second conventional FSK demodulator. Block diagram of the demod-remod technique. Next, experimental results are presented that demonstrate the performance of the demod-remod algorithm for two different signal power separations.
Phase noise is shown to be a major limitation on the performance of the technique.
The characteristics of phase noise, as well as methods used to combat it, are also described. Finally, quantitative guidelines defining the scenarios for which the demod-remod technique can effectively demodulate both the primary and secondary signals are given. Inc. All rights reserved.