基于Volterra滤波器的非线性窄带主动噪声控制系统

摘要

窄带主动噪声控制( narrowband active noise control, NANC)技术已广泛用于窄带噪声的抑制中。但是实际声学环境中,往往存在非线性扰动,使得初级噪声在相消点易产生非线性扭曲,单纯的线性NANC系统难以将其滤除。考虑到实际中窄带噪声受非线性扭曲后表现出的特点,提出了一种基于Volterra滤波器的新型非线性NANC系统。该系统最大的特点为线性滤波器与非线性滤波器是独立的,不但能有效的降低受非线性影响的窄带噪声,而且通过线型滤波器可以剔除噪声中的基频部分,只需单独调节非线性滤波器便可以滤除噪声中的高次谐波,为以后系统中非线性部分的进一步研究提供了依据。并使用了一种基于滤波-X LMS( FX-LMS)的算法得到控制滤波器权值更新方程,通过大量的仿真实验验证了Volterra滤波器的非线性NANC系统在抑制受非线性扰动或扭曲的窄带噪声中的有效性。%Narrow-band active noise control ( NANC) technology has been widely used in suppressing narrow-band noise. Howev-er, nonlinearity often exists in real-life acoustic field, which brings nonlinear distortion to the primary noise at the cancel ing point. Therefore, the linear NANC system alone wil suffer significant degradation in that case. With the characteristics of the distorted nar-row-band noise being taken into consideration, a new nonlinear NANC system based on Volterra filter is proposed. The new system can also kick out the fundamental frequency and the higher harmonics of the noise by the linear filter. An updated equation for the control filter weight is derived based on filtered-X LMS ( FXLMX) algorithm. Simulation experiments have verified the effectiveness of the proposed system in suppressing narrow-band noise distorted by nonlinearity.