Effects of harmonics on the frequency of oscillation as well as on the asymmetry of the resonance curves

Transforming the nonlinear equations representing the free and synchronized oscillations to linear ones with periodically varying coefficients, the complete solutions of oscillator equations to the first power of the tube parameters are obtained. The relation between frequency variation and harmonic contents is given. The effect of the harmonics on the asymmetry of the resonance curves of a synchronized oscillator is obtained for the first time. Experimental verification has been carried out, and the results agree well with the theoretical predictions.