Relationship between rms and instantaneous characteristics on nonlinear devices

Often a nonlinear transfer characteristic is given in terms of rms input and rms fundamental output. It is shown that this can be transformed into an instantaneous input/output characteristic which includes the odd-order components only. The even-order components have been irrevocably lost. The even-order terms of the instantaneous transfer characteristic can be obtained from the rms-input/dc-output characteristic. The instantaneous characteristic is required, for instance, when calculating distortion.