Reversibility principle of modulation-parametric interactions is formed, which is the basis for effective control of equivalent impedances in oscillation systems. A classification of oscillating systems in which there may be forces aimed at changing the effective reactive parameters and dissipation is given. Analytical approach for the study of modulation and parametric processes in oscillation and self-oscillation sys-tems under the small external signals influence is proposed. The heuristics of under-standing the modulation-parametric interactions reversibility are demonstrated. On the basis of the formulated and substantiated principle of reversibility of modula-tion-parametric interactions, a “dissection” of the physical mechanism underlying it was carried out, and also demonstrated the mechanism of its effective practical ap-plication. The analytical approach implemented in the work combines the advantages of analytical methods based on differential equations, which most fully and accurately describe the objects and phenomena under study, with complex spectral methods, which provide the most compact notation of equations, a clear physical interpretation of the internal structure of signals and facilitate mathematical analysis.