振动调幅信号的循环平稳解调原理与应用  

The principle and application of cyclostationary analysis for demodulation of amplitude modulated signals

作　　者：丁康[1] 孔正国[2] 何志达[2] 

机构地区：[1]西安交通大学机械工程学院 [2]汕头大学机械电子工程系,广东汕头515063

出　　处：《振动工程学报》2005年第3期304-308,共5页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(50475095);广东省自然科学基金资助项目(04020082);广东省教育厅2002年"千百十工程"优秀人才培养基金资助项目(Q02105);智能制造技术教育部实验室开放基金资助项目(Imtsu-2002-12)

摘　　要：在具有齿轮、滚动轴承的机械设备故障诊断中,广泛使用解调分析方法进行故障特征提取。对其中的周期平稳信号,通过循环自相关函数分析,并利用函数在某些循环频率下的切片进行绝对值解调可解出信号的调制频率。对两组调制相加信号在对应于某个调制频率的循环频率处进行循环自相关函数的切片解调,可得到该组调制频率成分的解调谱,从而达到将幅值调制相加信号分离成单一幅值调制信号并进行有效解调的目的。仿真和对滚动轴承实验验证,该方法在低频和高频处分别切片都有很好的解调效果,且与理论推导一致。但是该方法存在解两相加信号时以两频率之差及其倍频作为调制频率解出的局限性。Demodulation analysis is widely used in the fault diagnosis of machines which are equipped with rolling-element bearings and gears. The cyclic autocorrelation function is used to analyse those machine signals which are quasi-stationary or cyclostationary. The absolute-value based demodulation is applied to analyse the slices of cyclic autocorrelation function as to specific cyclic frequency. Modulating frequency will be obtained by demodulating each specific slice of a composite signal including two amplitude modulated signals. The composition of amplitude modulation signals can be extracted into single modulation signals by using this method. Simulation and the experimental results of the rolling-element bearing verify the effectiveness of the method. However, two-harmonic-component-add signal which have no fault information will be demodulated as the frequency subtraction of the two frequencies while using cyclostationary analysis.

关 键 词：解调 循环平稳 绝对值分析 故障诊断 

分 类 号：TN911.72[电子电信—通信与信息系统] TP206[电子电信—信息与通信工程]