Robust stability of discrete-time systems using delta operators

The robust stability of discrete-time systems formulated in terms of the delta ( delta ) operator is discussed. That is, given the nominal characteristic equation P( delta ) of a discrete-time system, it is of interest to know how much the coefficients can be perturbed while preserving stability. A procedure to obtain the maximum intervals for a perturbed polynomial P( delta ) to still be stable is presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>