Farrow structure interpolators based on even order shaped Lagrange polynomials

Traditionally, the polynomial based interpolation filters have been implemented by using Farrow structure with FIR subfilters of even length. Defining a modification of the traditional Farrow structure, it is possible to implement Farrow structure with FIR subfilters of odd length. This recently introduced structure is a natural implementation form for even order Lagrange and spline based interpolators. But especially in the case of even order Lagrange polynomials the resulted filter doesn´t behave satisfactorily compare to its odd order counterpart. This paper states the problem concerning even order Lagrange based Farrow structure. Then a solution to this problem is also presented in this paper. The designed filter applied to a 16-QAM model, shows the validity of suggested modification.