During acute AF, there are multiple and discrete excitation wave fronts or reentry activities were found in both LA and RA, and bidirectional block regions could be shown.

The high energy range of acoustic excitation, the peaks of combustion noise and major discrete frequencies are identified.

By this method, for a real excitation discrete signal or a simulating signal, the response time series of a non-linear system can be easily obtained based on the Z-transform technique.