On Complimentary and sensitivity of generalized wave digital filters

In recent literature, a general theory has been developed to design low-sensitivity digital filter structures in the
z
-domain. These structures are two-ports with two inputs and two outputs and wave digital filters belong to this general class. This paper explores the significance of the para-unitary or complementary condition on generalized wave digital filters. Satisfying this condition allows, for example, the simultaneous generation of low- and high-pass filter outputs. There is discussion too of sensitivity and its significance to those generalized wave digital filter structures that do not satisfy the para-unitary condition.