| Communications Toolbox | |
An eye diagram is a simple and convenient tool for studying the effects of intersymbol interference and other channel impairments in digital transmission. To construct an eye diagram, plot the received signal against time on a fixed-interval axis. At the end of the fixed time interval, wrap around to the beginning of the time axis. Thus the diagram consists of many overlapping curves. One way to use an eye diagram is to look for the place where the "eye" is most widely opened, and use that point as the decision point when demapping a demodulated signal to recover a digital message.
To produce an eye diagram from a signal, use the eyediagram function. The signal can have different formats, as the table below indicates.
Representing In-Phase and Quadrature Components of Signal
| Signal Format | Source of In-Phase Components | Source of Quadrature Components |
|---|---|---|
| Real matrix with two columns | First column | Second column |
| Complex vector | Real part | Imaginary part |
| Real vector | Vector contents | Quadrature component is always zero |
| | Example: Curve Fitting for an Error Rate Plot | Example: Eye Diagrams | |
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