用51单片机的定时器和外部中断分别实现对方波信号的高频测频和低频测周，同时将测量结果显示在LED数码管上，如果加外围加分频模块，可实现很高的精度和很高的频率测量范围-With 51 single-chip timer and external interrupt signals, respectively, to achieve the other side of the high frequency wave frequency and low frequency measurement we