In the chaotic mode, the operating point of the nonlinear core does not reach a steady-state condition, and the voltage waveform contains multiple spikes with usually high magnitudes, Figure 7(a). Due to lack of the periodicity and a distinguishable waveform pattern, the frequency spectrum of the chaotic mode is continuous and includes all frequency components, Figure 7(b). Furthermore, the power frequency sampling of the chaotic mode represents one or more scattered areas on the Poincare map, Figure 7(c).