Design of digital fractional Hilbert transformers using allpass filters

This paper presents a new direct method for the design of fractional Hubert transformers (FHT). The method is based on the design of an allpass filter with desired characteristic. The parameter of the design are the phase width W, the value of the phase φ_W which defines W and α. It is proposed a closed form equations to compute FHT filter coefficients. Design examples are given in order to illustrate the method.