A note on the dual input discrete describing function
M. Rao, P. V. Gopi Krishna Rao · IEEE Transactions on Automatic Control · 1970
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 φ 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.