In this paper, a significantly efficient time-domain algorithm is presented to analyze a transmission line, loaded by a nonlinear component and driven by an arbitrary modulated signal. The proposed method provides the envelope of the solution and removes the redundancy of the calculations. The efficiency of this method is achieved in two major steps. First, an unconditionally stable algorithm for the nonlinear circuit is introduced; The derived equations are generated based on the finite-difference time-domain technique and the results are confirmed by those of the Leapfrog method. As the circuit is excited by a modulated signal, decreasing the computational time by using the unconditionally stable algorithm alone, is not practical. Therefore, in the second step, a new time-domain approach is presented and utilized simultaneously, based on separating the high and low frequency behavior of the modulated signal, which enables the advantage of unconditionally stable algorithm effectively. The accuracy of the presented method is confirmed by the Leapfrog algorithm. The comparisons from the given examples indicate that almost 99.97% of the CPU time is decreased by using the proposed method.

中文翻译：

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由任意调制信号激励的非线性负载传输线时域分析的快速方法

在本文中，提出了一种非常有效的时域算法来分析由非线性组件加载并由任意调制信号驱动的传输线。所提出的方法提供了解决方案的包络并消除了计算的冗余。该方法的效率通过两个主要步骤实现。首先，介绍了非线性电路的无条件稳定算法；推导出的方程是基于有限差分时域技术生成的，结果得到了 Leapfrog 方法的证实。由于电路是由调制信号激发的，单独使用无条件稳定算法来减少计算时间是不切实际的。因此，在第二步中，提出并同时使用了一种新的时域方法，基于分离调制信号的高频和低频行为，有效地发挥了无条件稳定算法的优势。Leapfrog 算法证实了所提出方法的准确性。来自给定示例的比较表明，使用所提出的方法减少了几乎 99.97% 的 CPU 时间。