First of all, a fair net is obtained by adding some places that make the net have only one T-invariant.

首先，基于网论t不变式的概念，把系统的网模型设计为一个公平网。

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This thesis introduces the Petri net and the Petri net model of a data link layer protocol, and illustrates the properties of the net with S-invariant and T-invariant.

本文介绍了Petri网和数据链路层协议的一个Petri网模型，并且用S不变式和T不变式证明了该网的活性及其它性质。

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The linear time-invariant filter can' t improve SNR of single frequency component.

线性时不变滤波不能提高单一频率分量信噪比。

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