PSpice Subcircuit with adjustable property

Discussion in 'General Electronics Chat' started by oscar0226, Jun 27, 2015.

  1. oscar0226

    Thread Starter New Member

    Jun 27, 2015

    I am trying to build a subcircuit on pspice 16.6.

    The subcircuit is a parallel-coupled open-circuited transmission line which consists of three ideal transmission line components and two resistors. The schematic is attached below.


    However, I do not want to specify the property value of the three transmission lines such as TD and Z0 since I wish to implement a bandpass filter which cascade pairs of the subcircuit but with different values defined.

    I would like to ask if there is any way I can implement this subcircuit with adjustable properties please?
    Such that I can define the values of the subcircuit in the property list like the way defining the TD and Z0 values of an ideal transmission line but with TD1,2,3 and Z01,2,3 instead.

    Thank you in advance.
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    The method used by Spice variants to vary parameters of components or subcircuits is called "setting parameters".
    For example, by setting the value of a resistor to be {k} instead of a numerical value, by including the directive .param k=12345 in the schematic (or netlist), the resistance value is set just before the simulation runs.

    Using this directive .step Param k 1K 1oK 1K will run the simulation ten times, with values of 1K, 2K, ..., 10K Ω. Each time, the resistance is changed just before the simulation runs. In LTSpice, other node voltages and branch currents can be plotted as a function of the varying resistance. In effect, the resistance becomes the independent variable of the simulation.
    I'm not that familiar with the graphic user interface of PSpice, but the concept of parameters originated in text-based PSpice.




  3. mvaseem


    Jan 31, 2014
    Seems like you want to control the various Z0 and TD values from top level. I tried following simple circuit using hierarchical block where TLINES are under the block and params are defined at top level.

    Furthermore you can sweep TD's and Z's using param sweep (.step command).

  4. oscar0226

    Thread Starter New Member

    Jun 27, 2015
    Thanks for all the replies! it works!