A new window for the design of cosine-modulated multirate systems

Recently, the authors of this paper studied the performance of a simple design scheme for synthesizing nearly perfect-reconstruction critically sampled cosine-modulated M-channel filter bank and transmultiplexer systems without nonlinear optimizations. In this design scheme, the windowing technique is applied for designing the prototype filter such that its 3-dB cutoff frequency occurs at ω = π/(2M). The conclusion was that the best results are achieved by using the Blackman window. In order to achieve even better results, a modified window is introduced by including the fourth term in the Blackman window, the constants in the proposed window are optimized to minimize amplitude and aliasing distortions for the given number of channels and for the given prototype filter order. Examples are included illustrating the benefits provided by the optimized proposed windows over the original Blackman window.