The statistical behavior of phase error for deficient-order secondary path modeling

When implementing active noise control (ANC) systems, the filtered-x LMS (FXLMS) algorithm is often used, where the secondary path transfer function between the output of the adaptive control filter and the error sensor has to be modeled. To model the secondary path precisely, the secondary path estimation filter should be of sufficient order. However, too large an order increases the computation load of the FXLMS algorithm. In this letter, the relationship between the modeling phase error and the order of the secondary path modeling filter is analyzed.