3.4 FREQUENCY RESPONSE 165
They-parameter equivalent circuit that satisfies these equations is shown in Figure E3.4.3(a).
V 1 V 2
−y 12
y 11 + y 12 y 22 + y 12 (y 21 − y 12 )V 1
I 1 I 2
1
1 ′
(a)
2
2 ′
+
−
+
−
Figure E3.4.3(a)y-para-
meter equivalent circuit.
(b)z-parameter equivalent
circuit.(c)h-parameter
equivalent circuit.
V 1 z 12 V 2
z 11 − z 12 z 22 − z 12
(z 21 − z 12 )I 1
I 1 I 2
1
1 ′
(b)
2
2 ′
+
− +
−
+
−
V 1 h 12 V 2 h 21 I 1 h 22 V 2
I 1 h 11 I 2
1
1 ′
(c)
2
2 ′
+
+
−
−
+
−
Equations (3.4.13) and (3.4.14) can be arranged as
V 1 =(z 11 −z 12 )I 1 +z 12 (I 1 +I 2 )
V 2 =(z 21 −z 12 )I 1 +(z 22 −z 12 )I 2 +z 12 (I 1 +I 2 )
Thez-parameter equivalent circuit that satisfies these equations is shown in Figure E3.4.3(b).
Theh-parameter equivalent circuit satisfying Equations (3.4.15) and (3.4.16) is shown in Figure
E3.4.3(c).
Equations (3.4.11) and (3.4.12) can be solved simultaneously to yield
V 1 =
y 22
y 11 y 22 −y 12 y 21
I 1 +
−y 12
y 11 y 22 −y 12 y 21
I 2
V 2 =
−y 21
y 11 y 22 −y 12 y 21
I 1 +
y 11
y 11 y 22 −y 12 y 21
I 2
By comparing these with Equations (3.4.13) and (3.4.14), one gets
z 11 =
y 22
y 11 y 22 −y 12 y 21
; z 12 =
−y 12
y 11 y 22 −y 12 y 21
z 21 =
−y 21
y 11 y 22 −y 12 y 21
; z 22 =
y 11
y 11 y 22 −y 12 y 21