有源降噪中电声器件频率响应的仿真研究

Simulation Study on Frequency Response of Electroacoustic Devices in Active Noise Control

为了研究有源降噪系统仿真时电声器件的频率响应对次级通路建模的影响,使用有限脉冲响应(Finite Impulse Response, FIR)滤波器模拟电声器件的频率响应曲线,并以FxLMS(Filtered-x Least Mean Square)算法为例,研究扬声器与传声器的频率响应对系统降噪效果的影响。仿真结果表明,在实际降噪应用中电声器件陡峭的频率响应曲线会对输入信号幅值造成衰减,产生幅值失配的现象,使控制系统的实际降噪量远小于理想电声器件模型,并通过不同情况下的降噪效果分析了电声器件对系统降噪量的影响。该分析方法为深入进行有源降噪系统研究提供了一种新的次级通道模型分析思路。

In order to reduce the influence of the frequency response of the electroacoustic device on the modeling of secondary path during Active Noise Control(ANC) system simulation, the frequency response curve of the electroacoustic device was simulated by using a Finite Impulse Response(FIR) filter. And the Filtered-x Least Mean Square(FxLMS) algorithm was taken as an example to study the effect of the frequency response of electroacoustic devices on the noise reduction of the ANC system. The results show that in the actual noise reduction applications, the steep frequency response curve of the electroacoustic device can attenuate the amplitude of input signal, resulting in a phenomenon of amplitude mismatch, which makes the actual noise reduction of the control system much smaller than the ideal electroacoustic device model. The effects of electroacoustic devices on the noise reduction system were analyzed based on denoising effects of different situations. This analytical method can provide a new analytical procedure for secondary path modeling for further research of active noise control system.