Oversampled cosine modulated filter banks with linear phase
H. Boleskei, Franz Hlawatsch · 2002
We introduce oversampled cosine modulated filter banks (CMFBs) and a new classification of (oversampled or critically sampled) CMFBs as odd-stacked and even-stacked. We propose the new class of even-stacked CMFBs which allows both perfect reconstruction (PR) and linear phase filters in all channels. We formulate conditions for PR and show that any PR CMFB corresponds to a PR DFT filter bank with twice the oversampling factor. We also show that the frame-theoretic properties of a CMFB and of the corresponding DFT filter bank are closely related.