An improved envelope algorithm for eliminating undershoots ?
According to the drawbacks of current envelope algorithms, we present an improved envelope algorithm based on cubic spline and monotone piecewise cubic polynomial interpolations. The new envelope can eliminate the undershoots and meanwhile keep the smoothness property. In addition, we show that the developed method is valid when it is applied to the Empirical Mode Decomposition for non-stationary signal processing.
envelope undershoot instantaneous frequency empirical mode decomposition (emd)