DFT modulated filter bank design for oversampled subband systems

Filter banks are widely used in digital signal processing, often integrated in a multirate scheme, to reduce the implementation cost and to improve al gorithmic performance. DFT modulated filter banks are commonly used to desi gn oversampled subband schemes. Oversampled subband schemes are attractive as they trade off between complexity gain and aliasing distortion. Ideally, the overall effect of a subband system is that of a pure delay, i.e. the s ubband system is perfectly reconstructing. In this paper we present design techniques for perfect and nearly perfect reconstruction oversampled DFT mo dulated filter banks, One of the disadvantages of a perfect reconstruction filter bank design is that the stopband attenuation of the filters is typic ally small, which could have a negative impact on intermediate subband oper ations such as subband adaptive filtering. Nearly perfect reconstruction fi lter banks can be designed to overcome this problem, leading to a better pe rformance of the intermediate algorithms. (C) 2001 Elsevier Science B.V. Al l rights reserved.