电路 第十六章 二端口网络

回路电流方程为:????1I?2I?1U?2U?)b(1016?图??1j??2j?21Ir???1I?2I?I?)3()2()1(022)22(222)12(2221211????????????????IjIIjUIrIjIjUIIj??????????由(3)式得:2111111IjjIjI???????,分别代入(1)和(2),并整理可得Z参数方程为:???????????212211)11(1)11()21(IjIjUIjIjU??????Z参数矩阵为:10????????????1111121jjjjZ例16-4在复频域内求如图16-11所示双口网络的短路导纳矩阵Y。**??????2R1R1i1i?2i?2i1:n1u2u1C2C1u?1116?图解这是一个含有理想变压器的二端口的Y参数的求解。列结点电压方程:)1()()(1)(1)()()()1()(1)()(1)(1)()11(111112222212111221211???????????????????????????sIsURsURsIsIsURsCsURsIsURsURsURRsC理想变压器特性方程的复频域形式为:???????????)2()(1)()()(2121sInsIsnUsU将(2)式代入(1)式,消去)(1sU?,)(1sI?,)(2sI?得:??????????????????)()()1()()1()()()1()()11(22122211212121211sIsURnsCRsURnRsIsURnRsURRsC所以:可见:)()(2112sYsY?,由于理想变压器是互易元件。例16-5如图16-12所示,N为一线性电阻网络,已知当V8?SU,??3R时,A5.0?I,?????????????????????212212122111)1()1(11sCRnRRnRRnRRRsCY