可以画出给定一组数据的包络谱和幅值，非常实用，直接导入matlab中即可使用-Can draw the envelope spectrum and amplitude of a given a set of data, very practical, direct import of matlab can be used

give you a 简单易懂的求信号的傅里叶频谱和包络谱-Straightforward demand Fourier spectrum and envelope spectrum