In acoustics, knowledge of the impulse response of a system is often important. While impulse responses may be measured, they may also be predicted using numerical methods. This work considers the generation of impulse responses from frequency-domain finite element solutions. It is shown that these impulse responses, obtained by inverse Fourier transformation, are noncausal. Through error analysis, it is demonstrated that the noncausality can be reduced by increasing the duration of a source signal used to excite a simulated system. It is found that increasing the source signal duration increases the dispersion-related phase error present in the simulated impulse responses. The findings of this study are used to simulate an impulse response for a system with a nonuniform, frequency-dependent, complex impedance boundary condition.

中文翻译：

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从频域有限元解计算脉冲响应

在声学中，系统的脉冲响应知识通常很重要。虽然可以测量脉冲响应，但也可以使用数值方法预测它们。这项工作考虑了从频域有限元解决方案生成脉冲响应。结果表明，这些通过傅里叶逆变换获得的脉冲响应是非因果的。通过误差分析，证明可以通过增加用于激励模拟系统的源信号的持续时间来减少非因果关系。发现增加源信号持续时间会增加模拟脉冲响应中存在的与色散相关的相位误差。本研究的结果用于模拟具有非均匀、频率相关、复阻抗边界条件的系统的脉冲响应。