Analysis of Stability Margins in a Class of Discrete Nonlinear Time – Invariant Systems via Tsypkin Criterion and Describing Function technique

In this paper, novel definitions of Phase and Gain Margins are introduced for a class of Discrete Nonlinear Time - Invariant Lur'e Systems. Also, Describing Function - Harmonic Balance technique and Tsypkin Criterion based algorithms are proposed for calculating practical Phase and Gain margins in such systems. The efficacy of the proposed algorithms is illustrated in a tutorial example.