Roundoff noise analysis of modified delta operator direct form structures

The roundoff noise and coefficient sensitivity performance of the delta operator realized recursive digital filters have been shown to be good under fast sampling. Recently it has been found out that in fixed point delta operator implementations limit cycles may occur. We have proposed a small but important modification into the delta operator which enables us to eliminate zero-input limit cycles completely if magnitude truncation quantization is used. In this paper, we study in detail the scaling and roundoff noise in the modified delta operator direct form structure when magnitude truncation is used