驻波管中介质板复透射系数的修正计算方法

为提高驻波管中复反射、复透射系数测试精度,基于驻波管中四传感器法,分析了透射管内透射反射波对测试精度的影响,推导出经修正的单层和多层介质板的复反射、复透射系数计算公式.通过对有机玻璃的测试,比较了透射管开口末端和吸声末端对测量结果的影响;通过对海绵与人造革复合结构的测试,比较了声波正、反向入射对复透射系数的影响.实验结果表明,修正公式能够提高驻波管中单层或多层介质板的复反射、复透射系数测试精度,降低对透射管末端吸声性能的要求.对多层均匀介质板,正、反两方向上的正入射复透射系数相同.

The Modified Computation of the Complex Transmission Coefficient of Acoustical Panel in Standing Wave Tube

In order to improve the measuring precision of the complex reflection coefficients and complex transmission coefficients in a standing wave tube,based on the four-microphone method,the affection that came from the transmission-reflection wave in the transmission tube was analyzed,and the modificatory formulas of complex reflection and complex transmission coefficients of single layer and multilayer panel were induced.With the experiment toward organic glass,the affection of measurement results which came from opening end and anechoic end was contrasted.With the experiment toward the composite structure of sponge and leatheroid,the affection of complex transmission coefficient which came from forward incidence and backward incidence of sound wave was contrasted.The experimental results show that modificatory formulas can improve the measuring precision of complex reflection coefficients and complex transmission coefficients in the standing wave tube,decrease the demand of the tube end.To multilayer acoustical panel,the complex transmission coefficients of multilayer both forward and backward incidences are definitely the same.