利用单片机编写成书，通过放大录播等电路，实现正弦信号的产生，并可以通过程序控制输出波的频率，并在数码管上显示当前频率。-Using SCM to write a book, taped by amplifying circuit, generating a sinusoidal signal, and can be programmed to control the output frequency of the wave, and displays the current frequency