# Transmssion lines

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1. Mar 28, 2017

### shivik89

1. The problem statement, all variables and given/known data
can someone help me solving this problem ?
A coaxial cable is driven by a pulse source with internal impedance of
1kohms, 1 V amplitude, square wave with duration of both positive and negative pulse is
800 ns, with negligible rise- and fall-time. The load impedance is 10 ohm.The characteristic ipedance of the coax line is 53 ohms.
Sketch the voltage at the end of the line as function of time for 250 ns.

2. Relevant equations

3. The attempt at a solution

Last edited: Mar 28, 2017
2. Mar 28, 2017

### CWatters

nS or uS?

Forum rules require you to at least make an attempt at a solution.

3. Mar 28, 2017

### shivik89

Thanks for the reply, can you help. it is asked in ns?

I tried calculating the reflection coefficent at the input and output but can't get an idea how the voltage will look like

4. Mar 28, 2017

### CWatters

Ok what happens at the start of the transmission line - think potential divider.

5. Mar 29, 2017

### shivik89

I guess at start.The 1V will be divided between the source resitance of 1 kohms and the characteristic impedance of the cable of 53 ohms. so the forward travelling wave is 53/(1000+53) *1 V ?

6. Mar 29, 2017

### CWatters

Yes so a wave/step up of that magnitude sets off down the cable. What happens when it gets to the other end? And what's the voltage that end until it arrives.