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Boundary Conditions

The complete solution is known when \Aand Vrare known. We need two equations to

find them; these can come from any two of the below quantities

1.    Sending end voltage.

2.    Sending end current.

3.    Receiving end voltage.

4.    Receiving end current.

5.    Receiving end impedance.

Normally the receiving end impedance and one of the others is available.

We find it useful to extend our knowledge of impedance to other points on the linę.

To do this we find it convenient to first define the concept of voltage reflection factor.

The definition introduced is a generalisation of the quantity already defined in the time

domain for resistive terminations. We will find that voltage reflection factor is one of the

most important concepts in transmission linę theory, and it will be seen to supplant a

purelyimpedanceviewpoint.