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VSS CoSimulation NL_S Nonlinear frequency response

ChrisG04

Hi,

This is regarding a problem encountered with VSS CoSimulation with circuit simulator APLAC_HB. The circuit is a simple low pass LC filter.

Basically I am not getting the same frequency response results in VSS for the Linear and APLAC Harmonic balance models (or even when regular harmonic balance is used). The circuit is shown in Fig.1 Below. The Circuit model with just AWR (non-VSS) works fine with both Aplac-HB and Linear-AC and shows identical results, this is shown in Graphs->Circuit (Fig.2).

Next the VSS simulator was used with the Linear-AC (LIN_S) Subcircuit. The VSS Model is showin in Fig.3 and the results for this in Fig.4. The blue curve in Fig.4 is the input and pink is output. Note this shows the same frequency response as the circuit simulator case.

The VSS simulaton with the Aplac-HB model is shown in Fig.5. The frequency profile shows a flat response (Fig.6). During simulation it was observed that the VSS simulator runs through the full range of frequencies and powers.

Wondered if anyone knows a solution for this. Unfortunately it won't allow me to attach the .emp file but if you need this please send me an email address.

Best Regards,

Chris.


Fig.1
Fig.1


FIg.2
Fig.2

fig.3
Fig.3


Fig.4

FIg.5
Fig.5

Fig.6
Fig.6

  • Hi Chris

    The error you are seeing here is due to the NL_S parameter FREQDEP being set to "Use Dataset closest to simulation Freq". In this case the simulation freq is 0Hz so the filter response will be ignored

    If you set FREQDEP to Auto or "All available Frequencies" you will get the correct frequency response for the case of Complex input.

    for real input, there is an issue with passband response which has been logged into Testtrack for resolution.

     I'll update the post here when that is fixed, and of course contact you direct.

     

    Best Regards,

    Steve

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