Impulse response functions (IRFs) and frequency response functions (FRFs) are fundamental quantities that describe the dynamic behaviour of a linear vibrating system in the time and frequency domains respectively. The acceleration IRF is of particular concern in this paper, because unlike the displacement and velocity IRFs it contains a Delta function as well as a decaying oscillation. The origin of this Delta function is shown to be due to the causality constraint rather than the system. To illustrate the characteristics of the IRFs and FRFs, simulations are presented for a single-degree-of-freedom system, and are supported by some laboratory experimental work. The acceleration IRF is partitioned into the impulse component (Delta function for the simulations) and the oscillatory component. They are separately transformed to the frequency domain to illustrate their effects in the accelerance FRFs for both simulated and measured data.

脉冲响应函数（IRF）和频率响应函数（FRF）是基本量，它们分别描述了线性振动系统在时域和频域中的动态行为。加速度IRF在本文中特别值得关注，因为与位移IRF和速度IRF不同，它包含Delta函数以及衰减振荡。该Delta函数的起源显示为因果关系约束而不是系统约束。为了说明IRF和FRF的特性，对单自由度系统进行了仿真，并得到了一些实验室实验工作的支持。加速度IRF分为脉冲分量（用于仿真的Delta函数）和振荡分量。