TDR plot showing a big spike and dip instead of a well behaved line

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   Andrew Zonenberg (azonenberg@ioc.exchange)'s status on Tuesday, 24-Dec-2024 21:21:23 JST Andrew Zonenberg

   Managed to tear myself away from holiday stuff long enough to look at the sim run for the QSGMII TX pair.

   It's decidedly less well optimized than the RX but, honestly, I want to get this thing out the door and it's probably good enough (S11 of -16 dB at 5 GHz, -13.6 dB at 7.5 GHz).

   TDR response shows the main thru line around 105Ω which is probably a meshing artifact, then a big high impedance spike (to 115Ω) early on with some ringing, then a big low-impedance dip (to 85Ω) at the connector launch.