TWO PORT NETWORK
1. (Z-parameters) Open circuit Impedance Parameters
Its use is premised on selecting the input port current, I1, and the output port current, I2, as independent electrical variables.
where the zij are called the z-parameters of a two-port network. Here, input and output voltages are expressed in terms of input and output currents. The equations are given below.
V1 = Z11I1 + Z12I2
V2 = Z21I1 + Z22I2
where, Z11, Z12, Z21 and Z22 are called the Z-parameters.
So the Z-Parameter can be found as follow:
The z-parameters are also called open-circuit impedance parameters since they are obtained as a ratio of voltage and current and the parameters are obtained by open-circuiting port 2 (I2 = 0) or port 1 (I1 = 0).
2. (Y-parameters) Short Circuit Admittance parameters
These parameters are obtained by expressing currents at two ports in terms of voltages at two ports.Thus, voltages V1 and V2 are independent variables, while I1 and I2 are dependent variables.
The equations are given below.
I1 = Y11V1 + Y12V2
I2 = Y21V1 + Y22V2
Where, Y11, Y12, Y21, Y22 are called the Y-parameters.
The y-parameters are also called short-circuit admittance parameters. They are obtained as a ratio of current and voltage and the parameters are found by short-circuiting port 2 (V2 = 0) or port 1 (V1 = 0).
So the Y-Parameter can be found as follow:
3. h-parameters: Hybrid Parameters
Equations for voltage at input port and current at the output port are given below.
V1 = h11I1 + h12V2
I2 = h21I1 + h22V2
The h-Parameter can be found as follow:
The h-parameters are also called hybrid parameters since they contain both open-circuit parameters (I1 = 0) and short-circuit parameters (V2 = 0).
4. (g-parameters) Inverse hybrid parameters
I1 = g11V1 + g12I2
V2 = g21V1 + g22I2
Here g12 and g21 are dimensionless coefficients, g22 is impedance and g11 is admittance.
5. (T-Parameters) or ABCD parameters Transmission Parameters
These are generally used in the analysis of power transmission in which the input port is referred as the sending end while the output port is referred as receiving end. These parameters can be obtained by expressing voltage and current at the output port.
ABCD parameters can be defined as following:
V1 = AV2 + B(–I2)
I1 = CV2 + D(–I2)
The transmission parameters express the primary (sending end) variables V1 and I1 in terms of the secondary (receiving end) variables V2 and ' -I2 '. The negative of I2 is used to allow the current to enter the load at the receiving end.
6. Conversion of Z-parameter in term of Y-parameter
7. INTERCONNECTION OF TWO-PORT NETWORKS
Two-port networks can be connected in series, parallel or cascade. the configuration listed below:
This can be concluded that if two-port networks with Z-parameters [Z]1,[Z]2,[Z]3,[Z]n , are connected in series, then the equivalent two port-parameters are given as
[Z]eq = [Z]1+ [Z]2+ [Z]3+ [Z]n
This can be concluded that if two-port networks with Y-parameters [Y]1,[Y]2,[Y]3,[Y]n, are connected in Parallel, then the equivalent two port-parameters are given as
[Y]eq = [Y]1+ [Y]2+ [Y]3+ [Y]n
When two 2-port network are connected in cascaded configuration then the T-parameter of equivalent two port network will be the Product of T-parameter of individual network.
networks have transmission parameters [A]1,[A]2,[A]3,[A]n, then the equivalent two-port parameter will have a transmission parameter given as
[A]eq = [A]1*[A]2*[A]3*[A]n