The Use of Admittance Diagrams in Oscillator Analysis

Much useful general information concerning the behavior of oscillators may be obtained by means of a graphical analysis based upon curves of electronic and circuit admittance. A curve of electronic susceptance versus electronic conductance and a curve of circuit susceptance versus circuit conductance are plotted in the same diagram. At points of intersection of the two curves the electronic and circuit admittances are equal in magnitude and phase. These points therefore indicate possible equilibrium values of frequency and amplitude. This method of analysis explains observed oscillator phenomena, such as amplitude and frequency hysteresis, dominance of one mode of oscillation over other modes, pulsing, and electronic tuning. The function of this paper is to present a summary of information previously found only scattered throughout the literature on oscillators.