New realizability criterion for digital filters with external disturbance and saturation arithmetic

An improved stability criterion for fixed-point state-space digital filters in the occurrence of external disturbance and saturation nonlinearities by using induced l∞ approach is presented. The realization of state-space digital filters which is free from limit-cycles is brought out by utilizing a better characterization of the saturation nonlinearities and free-weighting matrices. The proposed criterion promises exponential stability and also diminishes the influence of external disturbance to a prescribed induced l∞ norm constraint. The superiority of the suggested method for filter design is exemplified by means of numerical examples.