2D and Circuit Stacked Eye Diagram Plot

A stacked eye diagram creates a multiple display of two or more eye diagrams with the same unit interval bit time. A stacked eye diagram is a convenient way to compare a set of eye diagrams with the same unit interval.

1. Click Circuit > Results ( or right-click Results in the Project Tree) , select Create Eye Diagram Report, then select Stacked Eye Diagram Plot to open the New Report window.
2. In the Context group box, make selections on the following field or fields, depending on the design and solution type.

1. Solution field with a drop down selection list. This lists the available solutions, whether sweeps or adaptive passes.
2. Domain field with a drop down selection list. Whether this field appears, and the domains listed, depend on the Solution type and the report type and display type selected.
3. Show field with a drop down selection list. Whether this field appears depends on if differential pairs exist and are enabled.

3. In the Eye Parameters group box, set the Unit Interval and Offset to match the specification for the source or driver of the signal. The unit interval is required.
4. Under the Trace tab Primary Sweep group box, make selections on the following categories:

1. In the Category list, click the type of information to plot. For an Eye Diagram, Voltage is the usual Category.
2. In the Quantity list, click the value to plot. The unit interval used to generate the quantity must be the same as the one specified for the report.
3. In the Function list, click the mathematical function of the quantity to plot, typically <none>.
4. The Eye Diagram field displays the currently specified Quantity and Function. Edit this field directly. Note that invalid expressions are displayed in red.
5. Range Function — opens the Set Range Function window. This applies to the currently specified Quantity and Function.

5. In the X (Primary Sweep) group box, make selections for the following:

1. Select the Primary value(s) on the dropdown menu.
   To select an X component that is different on the Primary Sweep, click the [...] button to open the Select X Component window. This lets you specify the X component as you do the Y; that is, in terms of Categories which define the selectable Quantities, and Functions to apply. After making selections, OK the window to assign the X component.
2. If sweeps are available, select [...] to display a window that lets you select particular sweep or sweeps, or all sweeps.
3. The Families tab provides a way to select from valid solutions for sweeps where a simulation has multiple variables defined (e.g., for a parametric sweep). If so, the variables other than the one chosen as the X (Primary sweep), are listed under the Families tab with columns for the variable, the value, and an Edit column with an [...] button.

6. From the Families tab, confirm or modify the sweep variables that is plotted.
7. Click New Report.

This creates a new report in Project Tree, displays the report with the defined trace, and enables Add Trace on the Report window.

The function of the selected quantity is plotted against the swept variable values or quantities you specified on an eye diagram. The plot is listed under Results in the Project Manager window and the traces are listed under the plot. When you select the traces or plots, their properties are displayed in the Properties window. These properties can be edited directly to modify the plot.

8. Optionally, add another trace to the plot by following the procedure above, using Add Trace rather than New Report. The added trace becomes the lowest of the stacked eye diagrams.
   Note: The stacked eye diagram is very useful for comparing eye diagrams (e.g., for AMI analysis, stack the waveforms before and after the channel).

   • Sweep a variable and stack the resulting set of eye diagrams.
   • When Eye Measurements can be displayed, the Stacked Eye Diagram format displays the measurements in a convenient side column that does not block the chart.