Effect of initial phase in two tone separation using empirical mode decomposition

Empirical mode decomposition (EMD) is an adaptive method for nonlinear and nonstationary signal processing. Although the algorithm is easy to implement and widely deployed, its theoretical background and limitations remain uncertain. This paper investigates the performance of EMD in two tone separation problem, especially for the transition region between perfect separation and failure, with emphasis on the effect of the initial phase. Relationships between amplitude ratio, frequency ratio, initial phase and performance are derived.