Modified series and parallel adaptors that lead to reduced sensitivity in wave digital filters

By replacing multipliers in conventional series and parallel adaptors by digital subnetworks comprising multipliers whose constants are as far as possible machine representable, modified series and parallel adaptors are obtained whose operation is less dependent on multiplier constants that are not machine representable. Conventional and modified adaptors are then used to design several digital filters and the effects of coefficient quantization are investigated. The results obtained show that wave digital filters implemented with the modified adaptors are significantly less sensitive than filters implemented with conventional adaptors.