双水听器传递函数法低频测试及误差分析

A two-hydrophone transfer function method for measuring low-frequency acoustic propertics and its error analysis

在水声声管中用双水听器传递函数法测量水声材料的复反射系数。本文研究了传递函数的特点，提出了等反射系数曲线和等相位角曲线，还研究了传递函数的测量误差和复反射系数的计算误差，得出的结论是：合理选择双水听器位置参数，提高系统信噪比，修正水中声速，并采用交换通道法，在所要求的频率范围内使测量结果达到一定精度。文章还给出测试实例，与经典的驻波法结果一致。

The complex reflection coefficient of materials can be calculated from the transfer function measurement between two hydrophones in water-filled tube. The character of the transfer function, the reflection coefficient and phase contours were investigated. The measuring error of the transfer function and the calculation error of the complex reflection coefficient were discussed simultaneously. The conclusion is that the measurement results in the required range can be worked out with better precision by choosing the proper two-hydrophone position parameters, raising S / N and correcting the sound speed in water. Therefore, these can be compared with the results obtained by SWR method.