在前几章介绍过的电路分析方法中,网络的支路特性、工作频率和分析结果是用具体的数值来描述的。在分析线性网络时,为了获得某些用数值解法无法获得的优点,往往希望用变量来描述支路特性,得到的分析结果是某种符号网络函数而不是具体的数值。所谓符号网络函数,是指含有元件参数和频率等变量的转移电压比、转移阻抗、转移导纳、转移电流比等网络函数。对任何线性网络的分析,归根到底是解一组线性代数方程Ax=b。在第二章中已讨论了 In the circuit analysis methods introduced in previous chapters, the branch characteristics, operating frequency, and analysis results of the network are described in terms of specific values. When analyzing a linear network, in order to obtain some advantages that can not be obtained by numerical solution, it is often desirable to describe the characteristics of a branch with variables. The analysis result obtained is a symbolic network function rather than a specific numerical value. The so-called symbolic network function, refers to the component parameters and frequency variables such as transfer voltage ratio, transfer impedance, transfer admittance, transfer current ratio and other network functions. The analysis of any linear network, in the final analysis, is a set of linear algebraic equations Ax = b. It was discussed in Chapter Two