Hello,
 I am trying to simulate baseline wander effect in the ethernet 100 Mbit/s transmit path. I use test pattern from TP-PMD standart doc, scrambler with seed=390, ideal transformer with first winding
inductance 350uH on transmit and load ends and transmition line in the form of 2wire mtline.
 When I do AC analysis, I see second order HPF response with f3db≈65 kHz.
But I can't see any big and long base line offset. I see only little (no more than 50 mV) and short (1-3 us) offset.
Did anybody simulate this effect? With what problem could I confront?
 Many Thanks.

Hello,
after a long work on another theme, I returned to the 100 Mbit/s Ethernet project.
  I corrected binary-to-MLT-3 converter, and after applying BLW worst-case test pattern to the input of 4b/5b converter I saw a 53 bit time zero on output of scrambler. But I see baseline drift  only  if scrambler out connects directly to bin-to-MLT-3 converter.
  In my structure after scrambler there is a NRZ-to-NRZI converter, as in datasheet of NS  DP83816 and when I apply output of NRZ-to-NRZI block to input of bin-to-MLT-3 there is no any significant baseline drift.
Does anybody know,   Do I need a NRZ-to-NRZI converter between  scrambler and bin-to-MLT-3 converter?
Many Thanks.