Considering rotation machines like a motor, the vibration signals are of universal nonstationarity and the fault samples are usually very limited. 旋转机械如电机振动信号普遍存在非平稳性，同时对于某台设备已有的故障样本往往非常有限的。
Secondly, to the nonstationarity of diesel engine noise, this paper focuses on the extraction of time frequency feature using wavelet scalogram. 其次针对噪声信号的非平稳性，研究基于小波尺度谱噪声分量的时频特征分析。
美
['nɒnsteɪʃə'nærɪtɪ]
