<d1b2>
<azonenberg> It looks worse than it is, the high freq ringing is because i'm stimulating the probe with a 40ps pulse and it has some high pass effects going on. I'm going to add a ~500 MHz LPF in the next board rev which should smooth it all out
<azonenberg>
the reflection at ~10ns is off the end of the BNC as far as i can see, the compensation circuit doesn't actually do a ton to get rid of it. I'm going to see if there's anything i can do about that but not super hopeful
<azonenberg>
it's intrinsic in all R-C divider probes although this is a bit more evident than usual
<azonenberg>
Looking at the time and frequency domain traces aligned, i'm pretty sure the ripple in the S21 plot is caused by that reflection at ~10ns
<azonenberg>
causing destructive interference with the incident signal
<azonenberg>
the challenge is going to be figuring out what to do about it