Documentation

eyediagram

Generate eye diagram

Syntax

eyediagram(x,n)
eyediagram(x,n,period)
eyediagram(x,n,period,offset)
eyediagram(x,n,period,offset,plotstring)
eyediagram(x,n,period,offset,plotstring,h)
h = eyediagram(...)

Description

eyediagram(x,n) creates an eye diagram for the signal x, plotting n samples in each trace. n must be an integer greater than 1. The labels on the horizontal axis of the diagram range between -1/2 and 1/2. The function assumes that the first value of the signal, and every nth value thereafter, occur at integer times. The interpretation of x and the number of plots depend on the shape and complexity of x:

• If x is a real two-column matrix, eyediagram interprets the first column as in-phase components and the second column as quadrature components. The two components appear in different subplots of a single figure window.

• If x is a complex vector, eyediagram interprets the real part as in-phase components and the imaginary part as quadrature components. The two components appear in different subplots of a single figure window.

• If x is a real vector, eyediagram interprets it as a real signal. The figure window contains a single plot.

eyediagram(x,n,period) is the same as the syntax above, except that the labels on the horizontal axis range between -period/2 and period/2.

eyediagram(x,n,period,offset) is the same as the syntax above, except that the function assumes that the (offset+1)st value of the signal, and every nth value thereafter, occur at times that are integer multiples of period. The variable offset must be a nonnegative integer between 0 and n-1.

eyediagram(x,n,period,offset,plotstring) is the same as the syntax above, except that plotstring determines the plotting symbol, line type, and color for the plot. plotstring is a character vector whose format and meaning are the same as in the plot function. The default value is 'b-', which produces a blue solid line.

eyediagram(x,n,period,offset,plotstring,h) is the same as the syntax above, except that the eye diagram is in the figure whose handle is h, rather than in a new figure. h must be a handle to a figure that eyediagram previously generated.

Note

You cannot use hold on to plot multiple signals in the same figure.

h = eyediagram(...) is the same as the earlier syntaxes, except that h is the handle to the figure that contains the eye diagram.

Examples

For an online demonstration, type showdemo scattereyedemo.