Nonlinear System Oscillations: Harmonic Linearization Method
The method of describing functions is mainly used to analyze nonlinear dynamic systems in a single-frequency harmonic approximation. The method is also known as the method of harmonic linearization or harmonic balance method or the first harmonic method. The method directly arises from spectral and asymptotic methods as their first approximation. For the first time, the method was applied in 1934 by the Soviet scientist V. Kotelnikov to evaluate the performance of self-excited oscillation generators.