The use of a masking signal to improve empirical mode decomposition

Empirical mode decomposition (EMD) provides a new method for analyzing signals from a nonlinear viewpoint. EMD is defined by an algorithm requiring experimental investigation instead of rigorous mathematical analysis. We show that EMD yields its own interpretation of combinations of pure tones. We present the problem of mode mixing and give a solution involving a masking signal. The masking signal method also allows EMD to be used to separate components that are similar in frequency that would be inseparable with standard EMD techniques.