一、计数器是数字电路（或设备）中最常用的一种时序逻辑部件，它的主要功能是对数字脉冲信号进行计数，以及对某些系统进行顺序控制。计数器的状态图结构如图一所示。起始状态图中n为计数电路中所用触发器的个数。系统运行时总是从某一起始状态出发，并周而复始的循环，一次循 First, the counter is a digital circuit (or device) in the most commonly used a sequential logic components, its main function is to count the digital pulse signal, as well as the order of control of some systems. The state diagram of the counter is shown in Figure 1. The starting state figure n is the number of flip-flops used in the counting circuit. The system is always running from a certain starting state, and cycle again and again, one cycle