A novel approach to the synthesis of recursive digital filters with linear phase

The synthesis of recursive digital filters with linear phase is approached by means of existing approximation techniques. The design is based on a finite impulse response (FIR) filter that represents the ideal filter in terms of both magnitude and phase characteristics. The recursive digital filter with linear phase is then synthesized as an approximation of the FIR model where optimal Hankel approximation theory as well as the model reduction techniques are used. The causality and stability of the designed filter are guaranteed. This technique is used for designing both one-dimensional and two-dimensional recursive digital filters with linear phase, and is illustrated by a few numerical examples