Optimal Design of IIR Frequency-Response-Masking Filters Using Second-Order Cone Programming

The frequency-response-masking (FRM) technique proposed by Lim has proven effectiveness for the design of very sharp digital filters with reduced implementation complexity compared to other options. In this paper, we propose a constrained optimization method for the design of basic and multistage FRM filters where the prototype filters are of infinite-impulse response (IIR) with prescribed pole radius. The design is accomplished through a sequence of linear updates for the design variables with each update carried out using second-order cone programming. Computer simulations have demonstrated that the class of IIR FRM filters investigated in the paper offers an attractive alternative to its finite-impulse response counterpart in terms of filter performance, system delay, and realization complexity.