Abstract: Signal filtering and filter design techniques are disclosed. An interconnection circuit switchably couples an input and an output of an element that is operable to perform a signal filtering operation on a signal received at the input so as to provide a filtered signal at the output. This enables the element to be used to implement a series of cascaded signal filtering operations. An iterative filter design method and a data structure that enables control of the element and/or the interconnection circuit are also disclosed. According to another aspect of the invention, an element is operable to perform any of multiple signal filtering operations on a received input signal. Controlled selection of respective sets of filter parameters associated with the multiple signal filtering operations enables the element to be used to implement the signal filtering operations in parallel filtering paths.