How to set a port voltage

Liu Xiao
Liu Xiao Altair Community Member
edited September 2022 in Community Q&A

Hello everyone,

Thanks for your interest。

I wanna give one port Time-varying voltage and set other as 0 in schematic.

I'm not sure if I should set it in schematic or use time domain analysis. How can I set parameters for port 1 only if I use time domain analysis in postfeko?

Best regards,

David

image

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Best Answer

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited September 2022 Answer ✓
    Liu Xiao said:

    Hi,

    one more question, if I view the result in "trace - near field", will the result be based on Time Analysis?

    There is no difference in my model if I add the time signal or not.

    Hi @Liu Xiao,

    Now I know what you're looking for. You can do this with a little workaround:

    • Add your frequency near field result to a Cartesian graph
    • Add you time signal to the same graph and switch the independant axis to "Frequency":
      image
    • Add a new Trace to the graph and multiply the near field and the time signal:
      image

    Hope this helps!

    Best regards,
    Torben

Answers

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited September 2022

    Hi David,

    For time-varying signals you should use the Time Analysis in POSTFEKO. There is a simple example in the ExampleGuide, section G.

    Make sure to simulate a fitting frequency range for your time signal. Good videos can be found on YouTube:

    https://www.youtube.com/watch?v=ahb6SCsYhzY
    https://www.youtube.com/watch?v=GSUdAjzwH-o

    Best regards,
    Torben

  • Liu Xiao
    Liu Xiao Altair Community Member
    edited September 2022
    Torben Voigt_20420 said:

    Hi David,

    For time-varying signals you should use the Time Analysis in POSTFEKO. There is a simple example in the ExampleGuide, section G.

    Make sure to simulate a fitting frequency range for your time signal. Good videos can be found on YouTube:

    https://www.youtube.com/watch?v=ahb6SCsYhzY
    https://www.youtube.com/watch?v=GSUdAjzwH-o

    Best regards,
    Torben

    Hi Torben,

    thanks for your reply.

    I have two questions after watching the video.
    1. I have data on the voltage as a function of time for three ports. How do I input the data to a specific port?
    2. I want to achieve the above, should I focus on Time Analysis or schematic?

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited September 2022
    Liu Xiao said:

    Hi Torben,

    thanks for your reply.

    I have two questions after watching the video.
    1. I have data on the voltage as a function of time for three ports. How do I input the data to a specific port?
    2. I want to achieve the above, should I focus on Time Analysis or schematic?

    Hi David,

    The time signal will be applied to the excited ports. So I would suggest to excite Port 1 only.

  • Liu Xiao
    Liu Xiao Altair Community Member
    edited September 2022
    Torben Voigt_20420 said:

    Hi David,

    The time signal will be applied to the excited ports. So I would suggest to excite Port 1 only.

    Hi Torben,

    good idea! I will try it. When I do the Time Analysis, btw, will what I set the port value in schematic affect the final result? 

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited September 2022
    Liu Xiao said:

    Hi Torben,

    good idea! I will try it. When I do the Time Analysis, btw, will what I set the port value in schematic affect the final result? 

    No, a simple 1V voltage source should do.

  • Liu Xiao
    Liu Xiao Altair Community Member
    edited September 2022
    Torben Voigt_20420 said:

    No, a simple 1V voltage source should do.

    It is very helpful for me and I have one more question.

    How can I get result like this? 

    I think this should be solved by relying on Time Analysis. image

  • Liu Xiao
    Liu Xiao Altair Community Member
    edited September 2022
    Torben Voigt_20420 said:

    No, a simple 1V voltage source should do.

    Sorry, I didn't make it clear.

    What I mean is that I want to get the output data under a set of signals. The signal is the port voltage based on the time.

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited September 2022
    Liu Xiao said:

    Sorry, I didn't make it clear.

    What I mean is that I want to get the output data under a set of signals. The signal is the port voltage based on the time.

    Hi @Liu Xiao ,

    Unfortunately, I don't quite understand your question. The image seems to show the E-field over frequency. In POSTFEKO, you can view results over both time and frequency in Time Analysis.

    Best regards,
    Torben

  • Liu Xiao
    Liu Xiao Altair Community Member
    edited September 2022
    Torben Voigt_20420 said:

    Hi @Liu Xiao ,

    Unfortunately, I don't quite understand your question. The image seems to show the E-field over frequency. In POSTFEKO, you can view results over both time and frequency in Time Analysis.

    Best regards,
    Torben

    Hi Torben,

    how can I view the frequency domain result in Time Analysis? 

    Best regards,

    Xiao

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited September 2022
    Liu Xiao said:

    Hi Torben,

    how can I view the frequency domain result in Time Analysis? 

    Best regards,

    Xiao

    Hi @Liu Xiao,

    This picture shows it:
    image

  • Liu Xiao
    Liu Xiao Altair Community Member
    edited September 2022
    Torben Voigt_20420 said:

    Hi @Liu Xiao,

    This picture shows it:
    image

    Hi,

    one more question, if I view the result in "trace - near field", will the result be based on Time Analysis?

    There is no difference in my model if I add the time signal or not.

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited September 2022 Answer ✓
    Liu Xiao said:

    Hi,

    one more question, if I view the result in "trace - near field", will the result be based on Time Analysis?

    There is no difference in my model if I add the time signal or not.

    Hi @Liu Xiao,

    Now I know what you're looking for. You can do this with a little workaround:

    • Add your frequency near field result to a Cartesian graph
    • Add you time signal to the same graph and switch the independant axis to "Frequency":
      image
    • Add a new Trace to the graph and multiply the near field and the time signal:
      image

    Hope this helps!

    Best regards,
    Torben

  • Liu Xiao
    Liu Xiao Altair Community Member
    edited September 2022
    Torben Voigt_20420 said:

    Hi @Liu Xiao,

    Now I know what you're looking for. You can do this with a little workaround:

    • Add your frequency near field result to a Cartesian graph
    • Add you time signal to the same graph and switch the independant axis to "Frequency":
      image
    • Add a new Trace to the graph and multiply the near field and the time signal:
      image

    Hope this helps!

    Best regards,
    Torben

    Thank you so much and have a nice weekend!

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