Design of perfect reconstruction FIR filter banks using DFT-modulation

In this paper, we present a design method of perfect reconstruction (PR) FIR filter banks by discrete Fourier transform modulation (DFT-modulation). In a previous work, the implementation of cosine-modulated PR filter banks was shown to be easy to design and capable of fast processing. But this method is a little bit inconvenient because of its restriction on the filter length. In our new approach filter banks are implemented by DFT-modulation of a prototype filter with complex coefficients and this has some advantages over the previous work. Furthermore, we propose a optimization method using the Lagrange-Newton method. Finally, we give a design example and show this method to be effective.