振动频域特性与时域测量的分析  

Characteristics of vibration in frequency-domain and its analysis of measurement in time-domain

作　　者：李潮锐 LI Chao-rui(School of Physics,Sun Yat-sen University,Guangzhou 510275,China;National Demonstration Center for Experimental Physics Education,Sun Yat-sen University,Guangzhou 510275,China)

机构地区：[1]中山大学物理学院 [2]中山大学物理国家级实验教学示范中心

出　　处：《物理实验》2020年第2期12-15,共4页Physics Experimentation

基　　金：中山大学物理学人才培养支撑条件建设项目（No.J1210034）;中山大学本科教学质量工程项目（No.2018WL-ZLJG026,No.2019WL-ZLJG004）

摘　　要：通过测量音叉振动速度幅值和相位频率特性,得到共振吸收和色散频域特征,分析阻尼强度对共振吸收频谱宽度的影响.由时域测量得到不同阻尼情形的共振弛豫时间,研究共振吸收频谱宽度与弛豫时间的物理关联.采用离散傅里叶变换方法,从理论上探讨由共振弛豫时域测量数据获取共振吸收的频域参量.研究结果表明,若共振弛豫时间较长,意味着激发态能级宽度比较窄;反之,则是激发态能级宽度比较宽.With measuring the amplitude-and phase-frequency characteristics of vibration speed for tuning fork,its resonance absorption and dispersion in frequency-domain were obtained.The influence of damping on frequency spectrum width of resonance absorption was analyzed,and then the resonance relaxation time for different cases was measured in time-domain.The correlation between the frequency spectrum width and the relaxation time of resonance absorption was studied.Furthermore,the parameters of resonance absorption in frequency-domain were obtained from the data of resonance relaxation in time-domain using DFT.The results showed that the energy level width of excited state was narrower for longer resonance relaxation time;otherwise,the result was reversed.

关 键 词：音叉 受迫振动 共振吸收 弛豫时间 频率特性 

分 类 号：O329[理学—一般力学与力学基础] O482.532[理学—力学]