Farrow structured variable fractional delay lagrange filters with improved midpoint response
Haolin Li, Guy Torfs, Tarik Kazaz, Johan Bauwelinck, Piet M. A. Demeester · 2017
This paper describes improvements in the Farrow structured variable fractional delay (FD) Lagrange interpolation. The main idea is to replace the first sub-filter of the Farrow structure by a sinc-interpolation filter of half a sample period to achieve a superior FD approximation in the vicinity of half a sample period. Its primary advantages over classical Farrow structured FD Lagrange interpolators are the lower level of mean-square-error (MSE) over the whole FD range and the reduced implementation cost. Design examples are included, illustrating an MSE reduction of 50% compared to a classical Farrow structured interpolator while the implementation cost is halved.