Design of variable fractional delay filter using expansions of hyperbolic functions

In this paper, the design of variable fractional delay filter using expansions of hyperbolic functions is presented. First, the ideal frequency response is decomposed into the sum of hyperbolic cosine and sine functions. Then, the power series expansions of hyperbolic functions are used to implement and design variable fractional delay filter. Next, the infinite product expansions of hyperbolic functions are also applied to obtain another design method of variable fractional delay filter. Finally, the numerical examples are demonstrated to show the effectiveness of the proposed design approaches.