qp_kaiser Computes a finite impulse response (FIR) filter for use with a quasi-perfect reconstruction polyphase-network filter bank. qp_kaiser (nb, at, linear) qp_kaiser (nb, at) nb: Number of bands at: Attenuation linear: When not zero, minimum-phase calculation is omitted. This is an Octave function. This version utilizes a Kaiser window to shape the frequency response of the designed filter. Tha number nb of bands and the desired attenuation at in the stop-band are given as parameters. The Kaiser window is multiplied by the ideal impulse response h(n)=a.sinc(a.n) and converted to its minimum-phase version by means of a Hilbert transform.