Statistical Properties of the FXLMS-Based Narrowband Active Noise Control System with Online Secondary Path Modeling

摘要

Rotating machines such as diesel engines, cutting machines, fans, etc. generate sinusoidal noise signals that may be successfully reduced by narrowband active noise control (ANC) systems. In this paper, performance analysis of such a typical filtered-X LMS (FXLMS) based narrowband ANC system equipped with an online secondary path modeling subsystem is conducted in detail. First, difference equations governing the dynamics of the FXLMS for secondary source synthesis and the LMS for secondary path estimation are derived in terms of convergence of both mean and mean square. Steady-state expressions for mean square error (MSE) as well as the remaining noise power are then developed in closed forms. Extensive simulations are performed to demonstrate the validity of the analytical results.