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现有的水声管吸声系数测量的脉冲法,由于水声管高度的限制,存在低频限制。提出了基于“后置”“逆滤波的宽带脉冲声测试方法,在测量获得系统的传递函数后,换能器发射宽频短脉冲信号,然后对接收到的标准反射体和待测样本的反射信号分别进行逆滤波处理,恢复未经传递系统”污染“的反射信号,计算待测样品的反射系数和吸声系数。仿真实验分析了”后置“逆滤波相对于传统”前置“逆滤波的在低频测试方面优势。对橡胶材料样品进行了实验测试,无论在低频段还是中高频段,宽带脉冲法和CW(Continuous Wave)脉冲法测试结果均吻合较好。宽带脉冲法是一种有效的测试方法,其低频测试能达到350 Hz,能有效拓展低频测试范围。
The existing pulse method for measuring the sound absorption coefficient of a water acoustic tube has a low-frequency limitation due to the limitation of the height of the acoustic tube. A broadband pulse sound test method based on ”rear “ ”inverse filtering is proposed. After measuring the transfer function of the system, the transducer emits a broadband short pulse signal, and then compares the received standard reflector with the sample to be tested Of the reflected signal were respectively processed by inverse filter to recover the reflection signal and the sound absorption coefficient of the non-transmitted system “Pollution ”, and the simulation results of the “post ” inverse filter were compared with the traditional “Front ” inverse filter in the low frequency test advantages.Experimental testing of rubber material samples, both in the low frequency band and high frequency band, broadband pulse method and CW (Continuous Wave) pulse method test results are in good agreement Broadband pulse method is an effective test method, its low frequency test can reach 350 Hz, which can effectively expand the low frequency test range.