A New Low-sensitivity Second-order Allpass Section Suitable for Fractional Delay Filter Realizations

In this paper a new second-order digital allpass section with very low sensitivity for transfer function poles near z=0 is developed and investigated. It is shown that most of the allpass-structures-based fractional-delay (FD) filters are having such poles and there are no suitable allpass sections in the literature. The new section is ensuring high accuracy realization of FD filters even in a severely limited wordlength environment.