5Li Guozheng, Yang Jie, Pei Renqing, et al. Condition monitoring and fault diagnosis of black-box components of mechanical equipment[J]. Journal of Vibration, Measurement & Diagnosis, 2003, 23 (3) : 183- 187. (in Chinese).
6Jiang Ping, Jia Minping, Xu Feiyun, et al. Feature extraction of weak signal in machine fault diagnosis [J]. Journal of Vibration, Measurement & Diagnosis, 2005,25(1):48-50. (in Chinese).