一体化有源吸声终端实现及其在行波管测量中的应用
Utilizing vector hydrophones to achieve an active anechoic terminal in an acoustic tube
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摘要: 提出了一种利用矢量水听器在声管中实现一体化有源吸声终端的方法。该吸声终端采用矢量水听器作为传感元件,以实现入射波和反射波的分离,克服了传统双水听器声波分离方法中传感器间距及测量频率的限制,显著拓宽了一体化有源吸声终端的低频吸声频段。由声管中水声材料的测试原理出发,重点分析了吸声终端中传感元件灵敏度误差对吸声终端性能的影响,并给出了反射、透射系数的修正方法。实验结果表明:该有源吸声终端在100~2000 Hz频段内吸声系数可以达到0.98以上,测量得到材料的声压反射系数、声压透射系数及理论计算基本一致。Abstract: A new vector hydrophones based active absorbing terminal used for the anechoic terminal of impedance tube is presented in this paper. Based on this, the reflected and the incident waves can be separated, and hence the absorbing spectrum can be achieved in a wider low-frequency band. The method overcomes the limit of frequency and size by using the traditional two-hydrophone method. The effect of hydrophone sensitivity on the terminal's absorbing performance is evaluated, and a correction method of reflection and transmission coefficients is also provided. Experimental results show that the absorbing coefficient in the frequency band of 100~2000 Hz is over 0.98, which is agree well with the theoretical results.