卡诺图观察法分析组合逻辑电路无关项

Analysis of Don't-care Terms in Combinational Logic Circuits Based on Observing Karnaugh Maps

在对无关项输入所对应的输出进行分析时,教材上的方法是将无关项带入逻辑表达式,计算出结果。用带入逻辑表达式的方法比较麻烦,容易出错。本文提出了利用卡诺图观察的方法,直接观察出无关项对应的输出,无需计算可直接得出结果,该方法直观明了,不容易出错,使用非常方便。同时提出了利用圈"×"法可得到最简与或约束式的方法。

The don＇t-care terms corresponding outputs are always calculated via logic algebra. The calculation of switching functions via the logic algebra is a difficult task. This method is complex, so mistakes are usually made. In this paper, a directly observing disposal via Karnaugh Maps is put forward. Is this way, output can be directly read easily rather than calculated troublesomely, so fewer mistakes are made. This way is simply and intuitive. In additional, a way of simplifying minimum And-Or constraint function is brought forward via enclosing sign ＂×＂.