Continuous Adaptive Feedback Canceller Dynamics

This paper investigates the chaotic artifact (Entrainment) observed when correlated input signals are presented to an adaptive feedback canceller. By applying nonlinear analysis and iterating the equations of a simplified feedback canceller, we show that the phenomenon is inherent to a feedback canceller structure, where an adaptive filter is embedded in the closed loop. We also unify the previous attempts to explain this artifact with adaptive filter bias and ill conditioning of the input correlation matrix of the adaptive system.