有源消声系统中的电声阻抗规律及其应用  

An Impedance-Based Control System and its Application in Active Noise Control, Part Ⅱ:Electro-Impedance Theory and Measurement

作　　者：侯宏[1] 杨建华[1] 李辉 孙进才[1] 

机构地区：[1]西北工业大学应用物理系,陕西西安710072

出　　处：《西北工业大学学报》2001年第2期246-250,共5页Journal of Northwestern Polytechnical University

基　　金：国家自然科学基金! (1990 40 0 8);航空科学基金资助! (97I5 312 2 )

摘　　要：运用电力声类比方法 ,研究有源消声中声源电声阻抗变化规律。首先给出动圈式扬声器总输入电阻抗表达式 ,并分析了声源辐射阻抗对电阻抗的影响关系 ;其次研究了在声抑制和声吸收两种消声状态下 ,次级源电阻抗的变化规律 ,并推导了换能器输入电压与输出振速间的关系 ;最后设计了交流电桥 ,实际测量了两种消声状态下 ,若干频率时次级扬声器电阻抗规律 。To our best knowledge, there still does not exist any impedance based noise control system made or designed in China. The first part of our research on such a control system was reported in Ref.[5] . In our experimental research, we needed the general input electro impedance for a coil driven loudspeaker and we derived eq.(1) as its expression according to well known principles. In section 2, we discussed in much detail the variation of the input electro impedance with radiation impedance for two noise reduction strategies; the actual variations are shown in Fig.2. In section 3, we discussed the conversion of the problem of finding the optimal strength of a sound source into that of finding the optimal input electro impedance for two noise reduction strategies; the actual conversion factors for amplitude and phase respectively can be taken from curves in Fig.4. Finally, we measured the input electro impedance of the secondary loudspeaker for two noise reduction strategies in a semi anechoic chamber. Fig.6 shows the measured values which agree fairly well with theoretical analysis.

关 键 词：有源消声 辐射阻抗 电阻抗 扬声器 电声换能器 

分 类 号：TB535.2[理学—物理]