Adaptive filters realized with second order sections

Adaptive digital filters are currently used in many communication systems for echo cancellation, channel equalization, and adaptive noise cancellation. Most practical applications presently use adaptive finite impulse response (FIR) digital filters because they are well behaved in terms of convergence and stability properties. This paper presents an adaptive algorithm that operates with a parallel form infinite impulse response (IIR) filter structure for applications in which an FIR filter requires too much computation. The new algorithm is derived mathematically and the results of computer experiments are presented to demonstrate its performance.