Example: Using Eye and Scatter Diagrams (Communications Blockset)

Communications Blockset

Example: Using Eye and Scatter Diagrams

The model below creates an eye diagram and scatter diagram from a complex sinusoidal signal. Because the decision time interval is almost, but not exactly, an integer multiple of the period of the sinusoid, the diagram exhibits drift over time. More specifically, successive traces in the eye diagram and successive points in the scatter diagram are near each other but do not overlap.

To open the completed model, click here in the MATLAB Help browser. To build the model, gather and configure these blocks:

Sine Wave, in the DSP Blockset DSP Sources library (not the Sine Wave block in the Simulink Sources library)

Set Frequency to .502

Set Output complexity to Complex

Discrete-Time Eye and Scatter Diagrams

Set Diagram type to Eye and Scatter Diagrams

Set Sample time for plot update to 1/30

Running the model produces the plots below. In the eye diagram, one set of traces represents the real part of the signal and the other set of traces represents the imaginary part of the signal.

Scatter Diagrams Source Coding