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水声材料的许多声学特性一般可以通过对复反射系数和透射系数计算得到。本文提出一种新的自由场测量方法，即应用宽带脉冲压缩技术在消声水池中测量有限尺寸的大面积材料样品的性能参数，从而使这种标准测量的低频限被明显降低。除传统的回声降低和插入损失参数等外，两个新的参数——消声系数和去耦系数也在评价之列。文中对两块平板样品进行了实验测量，其尺寸约为１ｍ×１ｍ，测量频率范围为 ２～ ２０ｋＨｚ。
Many of the acoustical properties of hydroacoustic materials can generally be calculated from the complex reflection coefficient and the transmission coefficient. In this paper, we propose a new free-field measurement method that uses broadband pulse compression technology to measure the performance parameters of large-area material samples of finite size in a muffler cell so that the low-frequency limit of such a standard measurement is significantly reduced. In addition to the traditional echo reduction and insertion loss parameters, two new parameters, the noise reduction coefficient and the decoupling coefficient, are also evaluated. In this paper, two flat samples were measured experimentally, the size of about 1m × 1m, the measurement frequency range of 2 ~ 20kHz.