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Transient Simulation with coaxial cables

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André
2017-02-10
2017-02-10
  • André

    André - 2017-02-10

    Hey Guys,
    i want to simulate a reflexion of a voltagepulse on a coaxial cable with the transient simulation. The source is on the left site and of course, i can measure the voltage. The coaxial cable is nearly open ended with 1 MOhm to the ground. So in theory, the pulse should be reflected back to the source, but it isnt. I also cannot measure any voltage after the coax cable.
    Does anyone have an advice? Maybe the coaxial cable is not laid out for transient simulation?

    Thanks for your help

    André

    PS: I hope i paste the correct code :S

    <Qucs Schematic="" 0.0.19="">
    <Properties>
    <View=0,-98,938,800,1,0,0>
    <Grid=10,10,1>
    <DataSet=test_koax.dat>
    <DataDisplay=test_koax.dpl>
    <OpenDisplay=1>
    <Script=test_koax.m>
    <RunScript=0>
    <showFrame=0>
    <FrameText0=Title>
    <FrameText1=Erstellt von:="">
    <FrameText2=Datum:>
    <FrameText3=Revision:>
    </Properties>
    <Symbol>
    </Symbol>
    <Components>
    <GND *="" 1="" 80="" 160="" 0="" 0="" 0="" 0="">
    <GND *="" 1="" 300="" 160="" 0="" 0="" 0="" 0="">
    <R R1="" 1="" 300="" 130="" 15="" -26="" 0="" 1="" "1="" MOhm"="" 1="" "26.85"="" 0="" "0.0"="" 0="" "0.0"="" 0="" "26.85"="" 0="" "european"="" 0="">
    <COAX Line1="" 1="" 210="" 100="" -26="" 16="" 0="" 0="" "2.29"="" 1="" "17="" m"="" 1="" "1"="" 1="" "4="" mm"="" 1="" "0.9="" mm"="" 1="" "1="" m"="" 1="" "4e-4"="" 1="" "26.85"="" 0="">
    <.TR TR1 1 580 90 0 51 0 0 "lin" 1 "0" 1 "11 ms" 1 "11001" 1 "Trapezoidal" 0 "2" 0 "1 ns" 0 "1e-16" 0 "150" 0 "0.001" 0 "1 pA" 0 "1 uV" 0 "26.85" 0 "1e-3" 0 "1e-6" 0 "1" 0 "CroutLU" 0 "no" 0 "yes" 0 "0" 0>
    <Vpulse V1="" 1="" 80="" 130="" 18="" -26="" 0="" 1="" "0="" V"="" 1="" "1="" V"="" 1="" "0"="" 1="" "1="" ms"="" 1="" "1="" ns"="" 0="" "1="" ns"="" 0="">
    </Components>
    <Wires>
    <240 100 300 100 "V_k_ausgang" 260 30 23 "">
    <80 100 180 100 "V_k_eingang" 170 0 85 "">
    </Wires>
    <Diagrams>
    </Diagrams>
    <Paintings>
    </Paintings>

     
  • domispace

    domispace - 2017-02-10

    Hi André,

    Right, the coaxial cable is not supported in Transient analysis. See http://qucs.sourceforge.net/components.html

    Regards,

     
  • Claudio Girardi

    Claudio Girardi - 2017-02-10

    Hello André,
    as you suspected, the coaxial cable (and most other transmission lines) do not work in transient simulation. AFAIR, only the ideal transmission line works there (and transient simulations with transmission lines have often convergence issues)

     
  • Claudio Girardi

    Claudio Girardi - 2017-02-10

    oh, I forgot we had such a nice table :)

     
  • André

    André - 2017-02-12

    Thank you two for your help ;)

     

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