实测一组机械系统的振动信号，记录采样频率、采样点数，估计该组振动信号的均值、均方值、方差、自相关函数和功率谱，其中功率谱估计对比频率平滑与分段平滑的效率，针对分段平滑、分析不同平滑次数对功率谱估计的影响-Found a mechanical vibration signal system, the recording sampling frequency, sampling points, the estimated mean the set of vibration signals mean