中文说明：
本程序主要用于DDS算法的验证,可以生成正弦波，占空比可调的方波，三角波；其中频率控制字可调，生成波形的频率也可调。
English Description：
This program is mainly used for DDS algorithm verification, can generate sine wave, duty cycle adjustable square wave, triangle wave; The frequency control word is adjustable, and the frequency of the generated waveform is also adjustable