What is the principle behind standing waves?

Hi There,

Does anybody know where we get to have standing waves whenever the terminator of our transmission line is not equal to the characteristic impedance?
Are there any theory behind this?

Thanks!
Hono'o

 

[digitelcej]

In layman's terms, standing waves are created on a transmission medium when the physical wavelength of the transmitted frequency (as perceived by the transmitter) is not equal to the electrical wavelength of that same frequency, resulting in some of the energy not being transmitted, but rather remaining on the transmission line (hence the term "Standing Wave&quot. Think of it as water being pushed through a hose by a faucet, but part of the water does not exit the hose and in fact begins returning toward the faucet, colliding with the other water being pushed out and resulting in less water transiting the hose.

http://www.anixter.com/techlib/d0500p01.htm

has some technical tests which examine the action of standing waves as a result of impedance mismatch. You might want to look at Levels Lab Reports and particularly Reports 2 (Increased performance of Matched Systems) and 4 (Return Loss and its Effect on Network Performance).

Cheers