用Teechart5控件实现的虚拟示波器，上位机部分源代码！接口为USB，具有图像采集，取点，显示周期，峰峰值，打印等简单功能。-a virtual oscilloscope achieved with Teechart prov5 and USB interface,source code of Host part! With image acquisition, check-point, display cycles, peak-peak value, print and other simple functions