Design of half sample delay IIR filter using continued fraction expansion

In this paper, the design of half sample delay IIR filter is presented. First, the continued fraction expansion (CFE) and its recursive computation are reviewed briefly. Then, the CFE of square root function is applied to design half sample delay IIR filters with various orders. Next, the comparison with conventional maximally flat IIR allpass filter is made and implementation issue is also addressed. Finally, several design examples are illustrated to demonstrate the effectiveness of the proposed method.