0 Replies Latest reply on Jun 20, 2016 3:50 AM by 9dc1212f-cb89-8a24-0100-014e727abccf

    REFERENCE IMPEDANCE while extracting s parameters

    9dc1212f-cb89-8a24-0100-014e727abccf

      Below is the topology that i have used for simulation, i have used scattering parameters of 5 inch trace for simulation

       

       

      so while extracting s parameters there is an option of selecting reference impedance i extracted s parameters for two reference impedance cases 25 and 50 ohms.

       

       

      While doing time domain simulation including DRIVER   -   S-PARAMETER OF TRACE   -    RECEIVER.

      observed from graph there is an offset while shifting reference impedance from 25 to 50 ohms, whereas signal quality is same. Whereas if i see individual return loss of 5 inch trace for the cases of reference impedance 25 and 50 ohms there is a difference, that means signal quality should change for both the cases.

       

      Can you please tell me why signal quality is not changing if return loss are different and reason for offset that has happened while changing reference impedance from 25 to 50 ohms?