做DDS时需要用到如三角波，正弦波之类波形的采样数据，这个函数可以产生任意采样点数和任意幅值的正弦波数据点。由该函数产生的数据很容易的转化为.mif文件-Do DDS when needed, such as triangular wave, sine wave like waveform of sampled data, this function can be generated in any sampling points and optionally the amplitude of t