Transfer characteristic analysis of All-phase Fourier Filter

This paper gives the transfer characteristic analysis of a novel digital filter-All-phase Fourier Filter(APFF for short).The derivation course from traditional FIR sub-filters to APFF is given in details. Based on this, the viewpoint that APFF’s performance can be improved by adding one front window or one back window is proposed. Filter designing simulation shows that, in contrast to frequency sampling method, the frequency characteristic of APFF is improved: slight ripples in pass-band and stop-band, narrow transition zone at the edge of transfer curve etc.