Design of non-uniformly spaced pseudo-QMF banks based on the spline function
Sunil Kumar, B. M. GANESHJ, R. C. JAIN · International Journal of Electronics · 1997
A computationally less complex technique using an optimal order spline as the transition function is proposed to design non-uniformly spaced pseudoquadrature mirror filters (pseudo-QMF) having linear phase and flat overall passband response. The proposed technique permits control of the transition bandwidth of filters along with minimization of integral squared error without generating Gibb's phenomenon. Sharp transition bands with reasonably large stopband attenuation can be obtained at relatively lower filter lengths, which can be very useful for subband coding of speech and image signals in which some bands may be required to be coarsely coded or discarded.