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The T-parameters of a 2-port network are
[T] = 
2 1 
. 1 1
If such two 2-port network are cascaded, the Z-parameter for the cascaded network is—
Correct Option: C
First the cascaded T-parameters of a network
| Teq = | | | | | |||||
| 1 | 1 | 1 | 1 |
| = | | | ||||
| 3 | 2 |
| = | | | ||||
| C´ | D´ |
the basic equation of transmission parameter
V1 = A′ V2 – B′ I2 (A)
I1 = C′ V2 – D′ I2 (B)
or V1 = 5 V2 – 3 I2 (C)
I1 = 3 V2 – 2 I2 (D)
In order to calculate Z-parameter of this cascaded network, we should make the equations in the form of V1 in terms of I1 and I2 and V2 is terms of I1 and I2 i.e.
| V1 = | I1 + | I2 (E) | ||
| 3 | 3 |
| V2 = | + | I2 (F) | ||
| 3 | 2 |
on comparing equation (E) and (F) with standard equation of Z-parameters i.e.
V1 = Z11 I1 + Z12 I2
V2 = Z21 I1 + Z22 I2,
we get
| Z11 = | ; Z12 = | |||
| 3 | 3 |
| Z21 = | ; Z22 = | |||
| 3 | 3 |
Hence alternative (C) is the correct choice.
