To convert \(Y\) parameters (admittance parameters) to \(ABCD\) parameters (transmission or chain parameters), you can use the following method. Hereβs a step-by-step guide:
### Given
- The \(Y\) parameters are defined as:
\[
\begin{bmatrix}
I_1 \\
I_2
\end{bmatrix}
=
\begin{bmatrix}
Y_{11} & Y_{12} \\
Y_{21} & Y_{22}
\end{bmatrix}
\begin{bmatrix}
V_1 \\
V_2
\end{bmatrix}
\]
### \(Y\) to \(ABCD\) Parameters Conversion
1. **Express the \(V\) and \(I\) relationship in terms of \(Y\) parameters:**
\[
\begin{bmatrix}
V_1 \\
V_2
\end{bmatrix}
=
\begin{bmatrix}
Z_{11} & Z_{12} \\
Z_{21} & Z_{22}
\end{bmatrix}
\begin{bmatrix}
I_1 \\
I_2
\end{bmatrix}
\]
Where \(Z\) parameters are the inverse of the \(Y\) parameters matrix.
2. **Calculate the inverse of the \(Y\) parameters matrix to get the \(Z\) parameters:**
\[
\begin{bmatrix}
Z_{11} & Z_{12} \\
Z_{21} & Z_{22}
\end{bmatrix}
=
\begin{bmatrix}
Y_{11} & Y_{12} \\
Y_{21} & Y_{22}
\end{bmatrix}^{-1}
\]
To find the inverse:
\[
\text{Inverse} = \frac{1}{\text{det}(Y)} \begin{bmatrix}
Y_{22} & -Y_{12} \\
-Y_{21} & Y_{11}
\end{bmatrix}
\]
where \(\text{det}(Y) = Y_{11}Y_{22} - Y_{12}Y_{21}\).
3. **Identify \(ABCD\) parameters:**
The \(ABCD\) parameters can be directly derived from the \(Z\) parameters:
\[
\begin{bmatrix}
V_1 \\
V_2
\end{bmatrix}
=
\begin{bmatrix}
A & B \\
C & D
\end{bmatrix}
\begin{bmatrix}
I_1 \\
I_2
\end{bmatrix}
\]
where:
\[
A = Z_{11} \text{ (or } \frac{Z_{11}}{Z_{21}} \text{ depending on the formulation)}
\]
\[
B = Z_{12}
\]
\[
C = \frac{1}{Z_{21}} \text{ (or } Z_{21} \text{ if in series)}
\]
\[
D = \frac{1}{Z_{22}}
\]
### Example
Suppose you have the following \(Y\) parameters:
\[
\begin{bmatrix}
Y_{11} & Y_{12} \\
Y_{21} & Y_{22}
\end{bmatrix}
=
\begin{bmatrix}
0.2 & 0.1 \\
0.1 & 0.3
\end{bmatrix}
\]
1. **Calculate \(Z\) parameters:**
\[
\text{det}(Y) = (0.2 \times 0.3) - (0.1 \times 0.1) = 0.06 - 0.01 = 0.05
\]
\[
\text{Inverse}(Y) = \frac{1}{0.05} \begin{bmatrix}
0.3 & -0.1 \\
-0.1 & 0.2
\end{bmatrix}
=
\begin{bmatrix}
6 & -2 \\
-2 & 4
\end{bmatrix}
\]
2. **Determine \(ABCD\) parameters:**
\[
A = Z_{11} = 6
\]
\[
B = Z_{12} = -2
\]
\[
C = -2
\]
\[
D = 4
\]
So, the \(ABCD\) parameters are:
\[
\begin{bmatrix}
6 & -2 \\
-2 & 4
\end{bmatrix}
\]
### Summary
To convert \(Y\) parameters to \(ABCD\) parameters, you first need to compute the \(Z\) parameters by inverting the \(Y\) matrix, and then use these \(Z\) parameters to derive the \(ABCD\) parameters. The specific formulas might vary slightly depending on the exact context and conventions used, but this approach outlines the general process.