Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [tdr]

36 questions
19
votes
8 answers

Electricity only flows in a complete circuit, so how does TDR (time domain reflectometery) work?

In high school we were all taught that electricity only flows in a loop. But it seems that one can send a "pulse" down an open conductor. This is used in a time-domain reflectometer. How is this possible? How can you send electricity down an open…
Jason
  • 301
  • 2
  • 5
3
votes
4 answers

Determining conductance / capacitance and inductance per unit length

How do you determine conductance / capacitance and inductance per unit for a cable experimentally? Is there a way to determine them with only a oscilloscope and a pulse generator?
Yoomo
  • 363
  • 1
  • 12
0
votes
3 answers

Frequency domain S11 conversion to time domain TDR

Below we see the S11 plot of a transmission line, the Wikipedia definition of the reflection coefficient as a function of S-params. As I see it, the S-param frequency domain plot comes from the time domain steady state. TDR is time domain in every…
ron398
  • 157
  • 1
  • 8
0
votes
1 answer

How can I convert from voltage TDR into impedance TDR

Based on the circuit below I have built the voltage based TDR diagram. Then I went to the ADS TDR simulation and constructed by the manual the circuit below. In the ADS circuit they say that IMPEDANCE=V/I=V/(delta(V)/R)=V*R/Voltage_drop_over_R I…
ron398
  • 157
  • 1
  • 8
0
votes
0 answers

time domain reflectometry interpretation of a simple circuit

I have constructed the following circuit in HSPICE,and it gives me the following waveform I know that we have the first wave hit node 3 then it goes back and again to node 3. But how we construct the impedance to time domain plot from this voltage…
ron398
  • 157
  • 1
  • 8
0
votes
1 answer

Three wire parallel transmission line (TDR)

I have a three wire parallel transmission line with a length of around 1000m. The wires are really close to each other. I want to sample the response of the transmission line for two different pulse shapes. Wire 1 will be used as the common…
clubpenguin
  • 1
0
votes
3 answers

time domain reflectometry on long cables

Is it possible to use time domain reflectometry on cables with a length of more than 100km? What kind of problems do time domain reflectometers on that long cables face?
Yoomo
  • 363
  • 1
  • 12
0
votes
1 answer

TDR unexpected results

I am using a signal generator to generate a long square pulse that is fed into a long transmission line consisting of two parallel wires. The transmission line is approximately 1km long. The near end is terminated with a 25\$\Omega\$ resistor, and…
Yoomo
  • 363
  • 1
  • 12
0
votes
1 answer

time domain reflectometer determining impedance

Lets say I have a 1km long transmission line with a characteristic impedance of 50ohm. With a pulse generator I inject a really long pulse (30µs) the pulse generators termination is also 50 ohm. The response will look like the image below T So the…
Yoomo
  • 363
  • 1
  • 12
0
votes
2 answers

TDR Device parameters

We are currently intending to purchase a TDR device (or maybe 2) to measure the impedances of various traces on PCBs but we are just at the beginning. Can you recommend some good devices or devices which are commonly used in the industry at the…
Tom L.
  • 8,059
  • 1
  • 22
  • 36
-1
votes
1 answer

what is the alternative method for time domain reflectometry

I have read that TDR is problematic because if we have many transmission lines in series which cause discontinuity to the source resistance ,then the closer TL's will mask the reading of the far TL from the source, so is when the rise time of the…
ron398
  • 157
  • 1
  • 8