Simplified design of low-delay oversampled NPR GDFT filterbanks

We propose an efficient algorithm for designing the prototype filters of oversampled, near perfect reconstruction (NPR), GDFT modulated, biorthogonal filterbanks with arbitrary delay. Given the analysis prototype, we show that the minimization of the stopband energy of the synthesis prototype, subject to NPR constraints on the frequency response of the distortion transfer function, can be expressed as a convex optimization problem. Our algorithm consists of initialization with the prototype of an orthogonal filterbank and then successive optimization of the synthesis and analysis prototypes. We compare our algorithm with previous methods and give several design examples.