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.