A New Method for Designing Constrained Causal Stable IIR Variable Digital Filters

This paper studies the design of causal stable Farrow-based IIR variable digital filters (VDFs), whose subfilters have a common denominator. This structure has the advantages of reduced implementation complexity and avoiding undesirable transient response when tuning the spectral parameter in the Farrow structure. The design of such IIR VDFs is based on a new model reduction technique which is able to incorporate prescribed flatness and peak error constraints to the IIR VDF under the second order cone programming framework. Design examples are given to demonstrate the effectiveness of the proposed approach