基于复调制ZOOM-FFT算法下阻尼比识别的研究

摘要

利用半功率带宽法识别系统的阻尼比是一种简单、常用的方法,但精度受到作图准确性及人员判读的经验所制约,严重时甚至不能准确拾取出半功率点.该文提出识别阻尼比的一种方法:细化-半功率带宽法,采用FFT变换对全谱进行识别,确定谱峰,利用复调制ZOOM-FFT算法对感兴趣谱峰处进行局部细化,最后结合半功率带宽法可有效提高阻尼比的识别精度.%Identify damping ratio of the system by using half-power bandwidth method is always a simple method, but its' precision is confined by the veracity of plotting and the operator's reading experience, even sometimes can not pick up the half-power point. This paper put forward a new method named zoom-half-power bandwidth method, which adopted FFT in identifying the spectrum peak in whole, then used ZOOM-FFT to zoom in the interested spectrum peak, at last combined with half- power bandwidth method in identifying damping ratio what can improve the precision.