51系列单片机的函数信号发生器的c语言的原代码，产生各种形状的信号,51 Series single-chip signal generator function of the c language source code, resulting in various forms of signal

（1）设计并制作一个具有高频率稳定度和高相位稳定度的低频函数发生器，频率可调，为1HZ-1KHz； （2）波形种类：三角波、正弦波、方波、锯齿波((1) a low frequency function generator with high frequency stability and high phase stability is designed and produced, and the frequency is adjustable for 1HZ-1KHz. (2) the t