Co cordinates and notation again - wykład

Co cordinates and notation again We consider the behaviour of a transmission line terminated as shown in Figure 2.6 in a
resistance ZL.
It might appear incongruous that we have chosen to represent what is a resistance
by the symbol ZL which is normally an indication of an impedance. The reason for this
choice of notation is that we will encounter in a later section dealing with the analysis
of transmission lines in the sinusoidal steady state, concepts and equations very similar
to those being uncovered here. It is common to borrow from that different context the
notation used therein although there is a certain inappropriateness in doing so.
Thus, if Vf at the load is known, we can calculate Vr. Note that when ZL = Z0
there is no reflection. This occurs when the line is terminated in a resistance equal to its
characteristic impedance.
Note that although we have not explicitly shown the arguments of Vf and Vr, Vf is
a function of z − ct and Vr is a function of z + ct. The equation just quoted has been
obtained by examining conditions at the load, and thus applies for the particular position
z = L, but for any time.
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