Stability of Digital Filters with State-Delay and External Interference

Abstract

This work addresses stability of interfered digital filters with state-delay and saturation arithmetic. By utilizing a quadratic Lyapunov functional and properties of saturation overflow, a new condition is established to ensure stability of interfered digital filters under the influence of saturation arithmetic and state-delay. The criterion is capable of finding minimum H∞ norm in the existence of external disturbance and ensures exponential stability in the nonexistence of disturbance. Further, an improved condition is obtained to ensure asymptotic stability of digital filters with saturation arithmetic. The established conditions are in linear matrix inequality framework and therefore computationally less demanding. It is shown that the stability criteria presented in this study are less stringent than few existing stability results. With the help of numerical examples, superiority of the presented approach is demonstrated.