High-order error feedback for noise reduction in state-space digital filters

This paper considers the problem of designing the optimal coefficients of high-order error feedback schemes for state-space digital filters. A technique for the reduction of the output noise variance in state-space digital filters is developed by means of the high-order error feedback consisting of a FIR digital filter. The optimal error feedback structure using all the elements of the coefficient matrices in the FIR digital filter is derived. A numerical example is also given to illustrate the utility of the proposed technique.