rect3.pro是idl拟真的3种不同长度的矩形波以及对应的频谱用以检测时长乘以带宽等于固定值，spect_test.pro是拟真不同的窗口函数以及对应的频谱-idl immersive rect3.pro is the three kinds of different lengths, as well as the rectangular-wave spectrum for the detection of the corresponding length of time equal to a fixed value multiplied by the bandwidth, spect_test.pro is different virtual reality as well as the corresponding window function spectrum