)???Y???=(rXY*rYY)???Y?????????(projection??????of??????X?????????onto??????Y???)(10) Notes on the Mathematics In embodiments of the present invention based on the mathematical formulations given above, the signals are treated as vectors in time; when a time-domain signal xi[n] is transformed (e.g. by the STFT) into a time-frequency representation Xi[m,k] where m is a time index and k is a frequen