在频域分析中，包络谱分析是一种十分有效的信号处理手段。利用包络谱分析能够准确得出故障频率，能够直观判断故障类型。本文件将包络谱分析直接做成了一个子VI，方便信号处理程序直接调用。(In frequency domain analysis, envelope spectrum analysis is a very effective signal processing method. The fault frequency can be accurately obtained by using envelope spectrum analysis, and the fault type can be judged intuitively. This paper will envelope spectrum analysis directly into a sub VI, to facilitate the direct signal processing program calls.)