Roundoff noise minimization in a modified direct-form deltaoperator IIR structure

摘要

Among various direct-form delta operator realized filternstructures, the delta transposed direct-form II (ΔDFIIt) has beennshown to produce the lowest roundoff noise gain in finite wordlengthnimplementations. Recent analyses focus on the optimization of the freenparameter Δ of the delta operator, with scaling of the structurento prevent arithmetic overflow. This paper proposes a modifiednΔDFIIt second-order section in which the Δs and filterncoefficients at different branches are separately scaled to achievenimproved roundoff noise gain minimization. Expressions for the filterncoefficients are derived, and reduction of roundoff noise gain isnverified by numerical examples