4 views

A two-port network is represented by $\text{ABCD}$ parameters given by

$$\left[\begin{array}{c} \mathrm{V}_1 \\ \mathrm{I}_1 \end{array}\right]=\left[\begin{array}{ll} \mathrm{A} & \mathrm{B} \\ \mathrm{C} & \mathrm{D} \end{array}\right]\left[\begin{array}{c} \mathrm{V}_2 \\ -\mathrm{I}_2 \end{array}\right]$$

if port-$2$ is terminated by $R_L$, then input impedance seen at port-$1$ is given by

1. $\frac{\mathrm{A}+\mathrm{BR}_{\mathrm{L}}}{\mathrm{C}+\mathrm{DR}_{\mathrm{L}}}$
2. $\frac{\mathrm{AR}_{\mathrm{L}}+\mathrm{C}}{\mathrm{BR}_{\mathrm{L}}+\mathrm{D}}$
3. $\frac{\mathrm{DR}_{\mathrm{L}}+\mathrm{A}}{\mathrm{BR}_{\mathrm{L}}+\mathrm{C}}$
4. $\frac{\mathrm{B}+\mathrm{AR}_{\mathrm{L}}}{\mathrm{D}+\mathrm{CR}_{\mathrm{L}}}$