Linear phase cosine modulated maximally decimated filter banks with perfect reconstruction

In this paper a new type of maximally decimated FIR cosine modulated filter bank is proposed. Each analysis and synthesis filter in this filter bank has linear phase. We can design the system to have approximate reconstruction property (pseudo-QMF system) or perfect reconstruction property (PR system). The filter bank is paraunitary in the PR case. Although there are 2M channels in the new system, the cost (in terms of design and implementation complexity) is comparable to that of an M channel system. Correspondingly, the coding gain of the new system is also comparable to that of a traditional M channel system (rather than a 2M channel system). Examples will be given to demonstrate that very good attenuation characteristics can be obtained with the new system