Capacitance Definitions for Parametric Operation (Correspondence)

The purpose of this note is to reconcile the various definitions of nonlinear or equivalent time-varying capacitance which appear in the literature concerned with parametric devices. The problem considered is one of a nonlinear reactive element, let us say a capacitance, which is pumped by strong pump source at frequency f_p and which couples two circuit modes at frequencies f_{s and f}sub i/, usually called the signal and idling frequencies. For parametric operation we demand either f_p=f_l + f_s or f_p = f<sub>l - fs_.