matlab实现的阶次分析算法，用于变转速机械故障特征提取，可运行，包含寻找脉冲时刻，等角度时刻，数字跟踪滤波，样条差值等步骤(The order analysis algorithm realized by Matlab is used to extract the fault features of variable speed machinery. It can run, including searching for pulse time, equal angle time, digital tracking filtering, spline difference and other steps)