Hello,(adsbygoogle = window.adsbygoogle || []).push({});

So I have a circuit where I input a square pulse with a source impedance and load impedance (which are just pure resistors) each of which can be varied and a transmission line circuit connecting them which is made up of resistors, capacitors, inductors in a lumped element model. I set the load impedance to open circuit and vary the source impedance until Vin (the voltage after the source impedance but at the input to the transmission line) shows only a transmitted pulse and single reflected pulse on an oscilloscope.

This is what I believe is source matching where the source impedance is equal to the characteristic impedance. What I am trying to calculate is the attenuation of the voltage from the input to the output and hence the attenuation coefficient. If I say the transmitted pulse is V1 and the reflected pulse is V2 BUT the reflected is a combination of V1 and the backward travelling wave. As I understand it the attenuation is for forward or reverse travelling wave only. So do I just subtract one from the other and use the difference to work out the attenuation coefficient? i.e. V3=V2 - V1 and so attenuation is V3/V1?

I am very new to this so any help or guidance would be appreciated! Thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Determine attenuation of voltage in transmission line

**Physics Forums | Science Articles, Homework Help, Discussion**