无规入射散射系数测量中的声能衰减分析

用脉冲响应同步平均法测量无规入射散射系数时，叠加后再经反向能量积分得到的声能衰减曲线，会受到不同脉冲响应中散射成分相关的影响．用统计声学的方法，从理论上分析了考虑散射成分相关时声能的衰减规律，该声能衰减曲线可以看作是由2个按指数规律衰减的曲线叠加而成的．通过理论和实测对用混响时间T10或T20估计衰减曲线早期的衰减速率所产生的误差进行了分析．

Analysis of Sound Energy Decay in Measurement of Random-Incidence Scattering Coefficient

In the measurement of random-incidence scattering coefficient by synchronized averaging of the impluse responses,the sound energy decay curve obtained by the backward integration of the squared averaged impulse will be influenced by the correlated components among these responses.The paper theoretically analyzes the energy decay with the method of statistical acoustics when the correlated components among these responses are taken into account.The energy decay curve can be seen as the sum of two curves following the exponential decay.The errors are analyzed in theory and with the measurements when using T_ 10 or T_ 20 to evaluate the decay rate of the initial of the energy decay curve.