Does anyone know how to find information on the derivation (rather than the definition and application) of Teager's Energy Operator, both for the continuous and sampled case. I have Kaiser's early papers "On a simple Algorithm to calculate the 'Energy' of a signal" and "Some useful properties of Teager's Energy operator" but these seem to stop short of giving the derivation.
This paper does a good job of explaining it, based on the energy of a mass-spring system.
R.C. Guido, "Enhancing Teager Energy Operator based on a novel and appealing concept: signal mass", J. Franklin Institute, 2019. https://doi.org/10.1016/j.jfranklin.2018.12.007