An improved ρDFIIt structure for digital filters with minimum roundoff noise

In this brief, a new efficient digital filter structure with minimum roundoff noise is derived. This structure can be block-diagrammed as the recently proposed direct-form II transposed (DFIIt) structure in ρ-operator, denoted as ρDFIIt, in which the first-order ρ operators are replaced with a set of second-order operators. The corresponding expression for the roundoff noise gain is obtained. The problem of how to choose these second-order operators is investigated in terms of minimizing the roundoff noise gain. Two design examples are given to illustrate the excellent performance of the proposed structure and to confirm the theoretical analysis.