Efficient fast filter bank with a reduced delay

The Fast Filter Bank (FFB) is a filter bank that uses a branching structure of cascaded subfilters to achieve a very low complexity. One drawback of the FFB is a larger delay when compared to conventional filter banks. In this paper, we propose a modified structure using a quad-channel subfilter block that can significantly reduce its delay. The proposed structure can also accommodate larger transition widths, which the FFB is unsuited for.