MATLAB: Is the plot in the Eye Diagram block showing multiple eye openings instead of a single eye opening

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In my model, I have an Eye Diagram block.  After running the simulation, the plot/scope for the eye diagram shows multiple eye openings, instead of a single eye opening that is centered at the middle of the time axes displayed.  How can I shorten the time axis or otherwise change some parameter to be able to display the single eye opening?  Below is a screenshot of what the eye diagram plot looks like:

Best Answer

This is the expected behavior.  The eye diagram scope is set up to show 2 symbols per trace.  As a result, we generally would expect to see two eye openings.  However, the eye openings may be shifted.  In the case of your example model, you can use the "Sample offset" parameter to adjust this shift (please refer to the relevant section of the documentation page for the Eye Diagram block).
In your specific example, if you set this parameter to 7, one of the two eye openings moves to the center of the screen, while the other one is split into two on the left and right edges of the screen.  This is shown in the screenshot below:
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