#### cmd

##### Member level 2

Hi,

I have some questions about this measurement parameter.

The formula of return loss is given everywhere RL=10*log(Pi/Pr) and RL=-20*log(abs(reflection coef))

This formulas gives positive values about return loss,however the measurement devices give negative values they calculate RL=10*log(Pr/Pi) and RL=20*log(abs(reflection coef))

The question i have is which one is the general description of return loss? In which ares we use positive and negative description?

How calculate cable and antenna analyzers or network analyzers the return loss?

Do they use Pi and Pr values or s11 parameter?

An another question is about frequency domain measurement;

In application notes it is written that, for cable loss measurements the cable far end should be short circuited. My question is what will be if we terminate the far end with open circuit? Does it change for cable loss measurement?

Also it is written that, for distance to fault measurement the far end should we terminate with load. If i terminate the far end with open or short to see also the end of the cable too? Does it affect my distance to fault measurement acuracy?

I have some questions about this measurement parameter.

The formula of return loss is given everywhere RL=10*log(Pi/Pr) and RL=-20*log(abs(reflection coef))

This formulas gives positive values about return loss,however the measurement devices give negative values they calculate RL=10*log(Pr/Pi) and RL=20*log(abs(reflection coef))

The question i have is which one is the general description of return loss? In which ares we use positive and negative description?

How calculate cable and antenna analyzers or network analyzers the return loss?

Do they use Pi and Pr values or s11 parameter?

An another question is about frequency domain measurement;

In application notes it is written that, for cable loss measurements the cable far end should be short circuited. My question is what will be if we terminate the far end with open circuit? Does it change for cable loss measurement?

Also it is written that, for distance to fault measurement the far end should we terminate with load. If i terminate the far end with open or short to see also the end of the cable too? Does it affect my distance to fault measurement acuracy?

Last edited: