数控分频器设计:对于一个加法计数器，装载不同的计数初始值时，会有不同频率的溢出输出信号。计数器溢出时，输出‘1’电平，同时溢出时的‘1’电平反馈给计数器的输入端作为装载信号；否则输出‘0’电平。

-NC divider design : an adder counter, loading the initial count value, have different frequency output signal of the overflow. Counter overflow, the output'1 'Level, Overflow at the same time the'1 'level feedback to the counter input signal as loading; Otherwise output'0 'level.