New to eye diagrams?

Pick an entry in Examples and follow the card and the hint under the screen. Every received symbol is drawn on top of the previous ones; where the traces leave an open “eye”, the receiver can tell the levels apart. NRZ has one eye, PAM4 has three stacked eyes. Hover over any control for a short explanation. The help page describes every setting and measurement in detail; the reference manual covers the theory and the complete design of the instrument.

Controls: drag a knob up or down, use the mouse wheel, or focus it and use the arrow keys. Shift gives fine steps, double-click restores the default.

Things to try

• Load Long backplane, no EQ, then set Equalizer to AUTO and watch the data turn green.
• Raise the noise until errors appear, then switch from PAM4 to NRZ. NRZ eyes are three times taller.
• Set persistence to ∞ and let the mask test count hits over time.
• Choose PRBS7 with a lot of loss and no equalization to see the discrete ISI paths.