A stability controlling-based approach for designing 1-D variable fractional delay all-pass filters

Abstract

Purpose

Variable fractional delay filtering is an important technology in signal processing; the research shows that all-pass variable fractional delay (VFD) filters achieve higher design accuracy than FIR VFD filters; therefore, the design, analysis and implementation of all-pass VFD filters are of great importance.

Design/methodology/approach

In this paper, a two-stage approach for the design of general 1-D stable VFD all-pass filters is proposed. The method takes the desired group delay range [N−1, N], where N is the filter order.

Findings

The design algorithm is decomposed into two design stages: first, a set of fixed delay all-pass filters are designed by minimizing a set of objective functions defined in terms of approximating error criterion and filter stability constraint. Then, the design result is determined by fitting each of the fixed delay all-pass filter coefficients as 1-D polynomials. A design example together with its comparisons with those of the recent literature studies is given to justify the effectiveness of the proposed design method.

Originality/value

An illustrating design example shows that the method proposed can achieve better filter performances than the existing ones.

Citation

Zhao, H., Li, S., Yang, H. and Zhou, Q. (2018), "A stability controlling-based approach for designing 1-D variable fractional delay all-pass filters", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 37 No. 6, pp. 2224-2231. https://doi.org/10.1108/COMPEL-01-2018-0053