The effect of nondegenerate one-frequency parametric regeneration

A general description is given of nondegenerate one-frequency regeneration in reactive elements with variable parameters, e.g., the parametric negative resistance effect in Josephson junctions. It is shown that this effect occurs only when the reactive parameter of the element periodically assumes a negative value. A general analytical expression is obtained for the impedance characterizing energy exchange between the reactive element and the external system; the cases of rectangular and sinusoidal modulation are considered. The physical nature of the parametric effect is examined, and the effect is discussed in the light of similar effects in variable-parameter systems.