A Note on the Dual Input Discrete Describing Function

The exact method of calculating the amplitude of the dither signal from the dual input discrete describing function (DIDDF) portrait is pointed out. It is shown that a previously established relationship between f and the system under consideration considerably simplifies its application. Further, it is established that only half the range of φ need be considered for a particular period of oscillation. Thus the utility of the DIDDF is considerably enhanced. Copyright © 1970 by The Institute of Electrical and Electronics Engineers, Inc.