Estimation of Teager energy using the Hilbert–Huang transform

A new method to estimate the Teager energy (TE) is presented here which uses an instantaneous energy expression and the Hilbert-Huang transform (HHT). The energy expression depends on the square of the instantaneous amplitude and digital frequency of the signal. This energy of the signal is estimated from the instantaneous energies of the intrinsic mode functions (IMFs), obtained from the HHT. The energy expression used for the TE ensures that the energy is always positive, and it is in agreement with the energy required to generate a sinusoid. It avoids the limitations in the use of the discrete TE operator (TEO), where for the output of the TEO to be positive and to give energies which match the energy required to generate a sinusoid, the signal must satisfy certain conditions. Numerical study on a data set of neuro-signals shows that these problems persist even when TEO is applied to the IMFs obtained from the empirical mode decomposition of the signal. Such a procedure is used in the Teager-Huang transform. There is a sharp drop in the number of negative values when IMFs are used, but the number is still not zero.