说明：  在进行Quartus仿真时，由于直接用自带的仿真工具无法查看正弦波，将仿真数据另存为tbl格式，用Matlab的程序调用该tbl文件，即可观察波形。当然，利用Modelsim更好。
(During Quartus simulation, waveform directly with their own simulation tools can not view the sine wave, Save the simulation data for the tbl format, using the Matlab program to call the tbl files, can be observed. Of course, using Modelsim better.)