SYNTHESIS OF IIR DIGITAL-FILTERS EXHIBITING SIMULTANEOUS AMPLITUDE AND PHASE RESPONSES FOR VLSI IMPLEMENTATIONS

A method is described for the design and implementation, in a double-l attice form, of selective linear phase digital filters. It is shown th at these filters are optimum in the sense that all available degrees o f freedom are used in adjusting the filter parameters to meet the spec ified characteristics. The designed filters, apart from satisfying the linear phase requirement, exhibit equiripple loss response over both the pass- and stopbands. A novel computationally efficient method base d on computing the complex cepstrum is proposed for the construction o f orthogonal double-lattice structures that realize the designed filte rs. It is based on the important property of cepstrum functions, namel y decomposing mixed sequences into both minimum and maximum phase sequ ences. Illustrative examples are given to support the theoretical anal ysis. (C) 1997 John Wiley & Sons, Ltd.