Teledyne LeCroy Eye Doctor II User Manual
Page 40
Eye Doctor II Software
Case 3, with CTLE equalization.
An interesting point about this waveform is we would expect higher CTLE boost to improve the eye, but it
doesn't do everything we hoped. That probably means there is some degradation besides the linear
slope of magnitude reduction with increasing frequency.
Next, following the procedure from case 2, we should change the data path so CTLE is only used on the
path to Clock Recovery, and then only use DFE to equalize the signal for EyeDrOut. Once again, we now
have the correctly clocked closed eye. However, unlike in case 2, the following screen-shot shows the out-
line of the eye as not being discernable. The difference is clear when comparing the closed eye picture in
case 2 to the following screen-shot. This signal is much more degraded.
Case 3, correctly clocked closed eye. No equalization applied on the data path.
38
922961 Rev A