A cascade implementation of a new IIR adaptive digital filter with global convergence and improved convergence rates

Recently a new type of adaptive IIR filtering algorithm called the prefiltering (PF) algorithm was presented. A new form of PF algorithm is presented here in which the adaptive filter is implemented as a cascade of second-order sections. The advantage of this form is that the low coefficient sensitivity of the cascade structure allows the step size to be significantly increased without causing instability of the adaptive process. The larger step size results in greatly improved convergence rates for the PF algorithm when it is applied to higher order systems