(一)前言实际工程中往往采用位移共振法来测定系统的固有频率。并由位移幅频特性曲线来计算系统的阻尼系数。当系统的阻尼较大时,其计算误差较大;当系统阻尼很大时,曲线的峰值变得不明显或者出现不了峰值时,这种计算方法就无法使用了。本文介绍的方法不但利用系统的幅——频特性,而且利用其相——频特性,在示波器中 (A) Preface The actual project often use displacement resonance method to determine the natural frequency of the system. The displacement amplitude-frequency characteristic curve is used to calculate the damping coefficient of the system. When the damping of the system is large, the calculation error is large. When the system damping is large, the peak of the curve becomes insignificant or there is no peak, so the calculation method can not be used. This article describes the method not only the use of the system amplitude-frequency characteristics, but also use the phase-frequency characteristics in the oscilloscope