数据选择器竞争冒险及其处理的仿真分析

The simulation analysis of multiplexer competition adventure and its processing

文献一般都是针对SSI小规模组合电路竞争冒险进行分析,实际上MSI中规模组合电路也会出现竞争冒险现象。司佑全,张学文在译码器竞争冒险及其处理的仿真分析(湖北师范学院学报(自然科学版),2015年第4期)分析了译码器竞争冒险,现以74LS151和74LS153组成函数发生器为例,利用卡诺图和Multisim仿真软件来分析数据选择器的竞争冒险,得到数据选择器变量数等于地址端数时,不存在竞争冒险;变量数大于数据选择器地址端数,当不需要扩展外部电路时也不存在竞争冒险;当需要扩展外部电路实现所得函数,卡诺图中存在相切的卡诺圈时可能会出现竞争冒险。利用数据选择器和译码器进行一定的组合再结合相关门电路就能实现多变量逻辑函数。

In general, ones perform analysis on the competition adventure with SSI small -scale combinational circuit in the literature. However, in fact, the middlingscale combinational circuit also often occur in the competition adventure. In this paper, as example, taking the composition 74LS151 and 74LS153 as function generator, by use of the Karnaugh maps and Multisim simulation software, the authors perform analysis on the multiplexer of competition adventure and obtain the results that if the multiplexer variable equal to the number of address terminals, there is no competition adventure ; while the number of variables is greater than the number of multiplexer addresses end and the external circuit dose not need to be extended, there exist some competition adventure. If some external circuit needs to be extended to come into being the function and there is a tangent Karnaugh map, the competition adventure may occur. By combinations of the multiplexer and decoder combined with certain door closing circuit, the multivariable logic function can be realized. The method of [ 1 ] to eliminate competition adventure decoder is also suitable for multiplexer.