Conditions for convergence of a delayless subband adaptive filter and its efficient implementation

This article considers the convergence characteristics of the delayless subband adaptive digital filters (ADFs) proposed by Morgan and Thi (see ibid., vol.43, p.1819-30, 1995). We derive a formula for the step-size parameter to ensure the convergence of ADPs and show that the derived formula enables self-adjusting of its value to ensure convergence regardless of the type of analysis filters employed or characteristics of the input signals. Consideration on the efficient implementation of the structure using short-length analysis filters is given through the results of simulations.