采用Labview设计一虚拟函数信号发生器， 通过数据采集卡输出波形信号，调节信号的相关参数，可观察示波器上波形的变化情况。-Using Labview to design a virtual function signal generator, through the data acquisition card output waveform signal, adjust the relevant parameters of signal, to observe changes of the oscilloscope waveform.