Abstract This work evaluates the effect of the excitation signal used when measuring the absorption coefficient on an impedance tube. This paper aims to offer some guidance on the selection of the excitation signal to perform sound absorption measurements using the impedance tube. Four possible excitation signals defined in ISO 10534-2 Standard were studied: two of them, random noise and two of them sine sweep signals. Some hypotheses tests were executed to assess the homogeneity of each measurement. The signal-to-noise ratio (SNR) was also computed to verify the measurement quality. The results show that the best performing approach was accomplished using a logarithmic sweep, giving more precise sound absorption curves with an SNR of 34.15 dB. Random signals reported similar SNR (greater than 30 dB) after executing an average with 100 repetitions.

中文翻译：

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激励信号类型对阻抗管吸收系数测量的影响

摘要 这项工作评估了在测量阻抗管上的吸收系数时使用的激励信号的影响。本文旨在为使用阻抗管进行吸声测量时选择激励信号提供一些指导。研究了 ISO 10534-2 标准中定义的四种可能的激励信号：其中两种是随机噪声，另一种是正弦扫描信号。执行了一些假设检验以评估每个测量的同质性。还计算了信噪比 (SNR) 以验证测量质量。结果表明，最佳性能方法是使用对数扫描实现的，可提供更精确的吸声曲线，SNR 为 34.15 dB。在执行 100 次重复的平均值后，随机信号报告了类似的 SNR（大于 30 dB）。