A systolic FxLMS structure for implementation of feedforward active noise control on FPGA

Active noise control (ANC) is an efficient technique to deal with low frequency noise that is difficult to be abated by noise barrier or sound absorbing material. Many successful ANC systems have adopted the feedforward filtered-x least mean squares (FxLMS) algorithm to reduce machinery noise. The noise canceling headset is another well known example, where the feedback control structure is favorable due to the small size. However, the feedback control structure is incapable of reducing broad band noise. Therefore, this paper investigates the feasibility of implementing the feedforward FxLMS algorithm in the noise canceling headset. Since the reference microphone has to be placed very close to the secondary source, we propose a systolic FxLMS structure that can be very efficiently implemented on the field programmable gate array (FPGA). Theoretical analysis and simulation results are presented to show the convergence behavior of the systolic FxLMS structure.