why the inductance and capacitance doesn't change the impedance while the cable length has been changed?The AC impedance, 50, 75 or 93-ohm takes into account the inductance and capacitance and is independent of the length of the cable. The terminating resistor should match this impedance.
You can try Gonzalez, Microwave Transistor Amplifiers, Chapter 1, for probably the best explanation I've ever seen. If you couldn't grok the Wikipedia article it is doubtful that his treatment would work any better for you.Thanks Papabravo
but i can't understand agian better.it seems i need a good refrence and explanation about it with picture and other physical image
Great minds think alike since that was the link I gave him as well.
No problem -- I appreciate the vote of confidencePB, I deleted my superfluous post. I hadn't noticed that you'd already posted the Wiki link.