On asymmetric FIR interpolators with minimum Lperror

The synthesis approach presented in this paper allows one to produce discrete-time filters whose approximation to an arbitrary delay is optimal in a minimax sense. These interpolators exhibit an equal-ripple behavior in their amplitude and/or phase characteristics. In contrast to linear phase FIR designs, the resulting impulse response is in general nonsymmetric. The synthesis method is based on the Fletcher-Powell minimization algorithm applied to the FIR filter tap weights. The technique may be profitably extended to the synthesis of any FIR characteristic having a desired phase response which is other than a multiple of T/2 delay.