约束项在数字电路设计中的应用

Application of Binding Terms in the Design of Digital Circuit

定义了两种不同性质的约束项,即“不会出现的”约束项和“具任意性”的约束项,并以一个同步五进制加法计数器为例,说明了分别应用这两种最小项以不同的方式设计电路,使所设计的数字电路最简单。最后,以一个能自启动的4位扭环形计数器的设计为例,说明了具体分析、合理应用约束项,避免产生新的无效循环,从而使所设计的4位扭环形计数器电路最简单且能自启动。

This paper defines first two kinds of binding terms of different quality, that is binding term of ＂no possibility of appearing＂ and ＂having arbitrary quality＂. Then it provides an example of synchronous additive counter of a system of five digits to show that the designed circuit is simplest among circuits using these two kind of binding terms. Finally it is shown that reasonable use of binding terms can avoid producing new ineffective cycles resulting in the designed four digits turn around ring counter is simplest and can start itself.