结构系统模态参数识别的最优采样频率点研究

Study on the Optimal Sampling Frequency of Identifying the Modal Paramenters in the Dynamic Structural System

在噪声环境下，要使识别出的任何参数偏差最小，需要确定最优的采样频率点。本文根据施力函数的性质，推导出了优化识别模态参数最优采样频率点的判据，并给出了相应的定理和公式。实际算例表明，最优采样频率点位置并不依赖于系统的输出，仅仅取决于激励的性质。

In a noisy environment,the optimal sampling frequencies must be determined so that any pa- rameter to be identified with a minimum variance. The criteria of the optimal sampling frequenciesare deduced that identify optimally the modal parameters according to the nature of the forcinfunction,and the related principles and formulae are given. The actual computation example shows that the optimal sampling frequency locations are found to be independent of the system response,and solely depend on the nature of the excitation.