也可通过列端口电压、电流
关系得到参数方程 I1
U 1?? Z1 I1??? Z 3 I2?? U 2
Z1
U 2??? Z 3 I2 ??I2 Z 2
+ U 1
Z3
I2
Z2
+ U 2
-
-
将 I1代入第一式并经整理，可得
1?? (1?? Z 1 )U 2???U ( Z 1?? Z 3?? Z 1 Z 3 )I Z 2 Z 2
T11
2
也可求得
1?? 1 U 2???I (1?? Z 3 )I 2
Z 2 Z 2
Z2 = 1 / T21
Z1 = (T11 -1) / T21 Z3 = (T22 -1) / T21
T21
T22
返回目录
16.4
二端口的联接
一、级联（ cascade connection ）（链联）
I1
I1??
I2??T
I1???
I2???
I2
+ +
T???
+ +
T????
+
+ -
-
-
-
-
U-
2
设
[T?]???? T11??T12????[T???]?????????????T11?? T12????? ?T??21
??
?T?????21 T22???
即
?U??? 1????T11
T12?????????????
U 2??????? I
?????? ?U?????? 1????T?11? T12???? U 2????
1????T21 ??
?????
?
I1
I1??
I2??
T
+ -
I1???
+ -
I2???
I2
+ -
+
T???
T????
+ +
- - -
I1
+ - 得
I2??
T
?? I2??I2 T???
+ -
T????
+
-
???U 1???????????????T11 T12???? U ????????????2????T11
???? I 1????T21 T22?????? I 2????T21
T12?????T11?? T12??????
????????????????
?? 1????T11 ?U????T21 ? I 1???得 结论
T12?????T11???T12?????? U 2???
????????????
T?? T?? T????
级联后所得复合二端口（ composite two-port） T参
数矩阵等于级联的二端口T参数矩阵相乘。上述结论可推 广到n个二端口级联的关系。
T1
T=[T1][T2] …. [Tn]
T2
... ...
Tn
