A new filter implementation strategy for Lagrange interpolation

Abstract

Fractional delays (FD) are used in DSP applications where accurate time delays are required. This paper introduces a new implementation technique for a maximally flat FIR FD filter, or Lagrange interpolator. The number of multiplications is reduced when compared with the direct-form FIR implementation plus coefficient update using Nth-order polynomials. The new structure is well-suited to implementation of a time-varying fractional delay.