Application of the Wigner distribution to nonlinear systems

A new way to study nonlinear oscillations is presented, based on Time—Frequency Analysis, a technique that allows the representation and study of the instantaneous spectral content of a signal. The investigation of nonlinear oscillations is an interesting subject in many areas of physics and engineering, especially in nonlinear optics where this phenomenon arises directly from the interaction of electromagnetic waves and matter. Here it is shown how Time—Frequency Analysis can clarify the nature of a free nonlinear oscillation, which is proven to have a peculiar yet physically reasonable instantaneous spectrum.