Handout 18: Dual-input describing functions Eric Feron April 5, 2004 Dual-input describing functions are for mixed signals (sinusoid + small constant signal) Approximating non-constant signals with constant ones Applications 1 Dual-input Describing function for switch nonlinearity 2 Dual-input describing function for switch nonlinearity - cont’d 3 Step response of 3rd order motor system 4