Eye Diagram Support VI

Owning Palette: Eye Diagram Measurements VIs

Requires: Jitter Analysis Toolkit

Formats data about waveform segments and optionally, a mask and eye height and width lines, into an array of values you can plot on an eye diagram.

Note  This VI appears on the block diagram when you add an eye diagram to the front panel. On the Controls palette, select Addons»Jitter Analysis to navigate to the eye diagram indicator.

Details  Examples

	eye diagram data is a cluster of data that defines the eye diagram you want to plot. Note  Height- and width-related cluster elements contain default data unless you use the Eye Height and Width VI before this VI to calculate those values. segments is an array of values that define portions of the waveform to plot in the eye diagram. start idx is the index within the original waveform of the first sample in the waveform segment. end idx is the index within the original waveform of the last sample in the waveform segment. ref crossing specifies the index number of the sample between start index and end index whose value falls at the crossing level. t min is the initial time in the eye diagram. t max is the final time in the eye diagram. v min is the minimum voltage value in the eye diagram. v max is the maximum voltage value in the eye diagram. unit interval is the time between level crossings in the eye diagram. height is TRUE if this cluster contains values that define the height of the eye opening. If height is FALSE, height time, top, and base contain default data. height time is the time at which the height measurements occurs. top is the upper voltage level of the eye opening. base is the lower voltage level of the eye opening. width is TRUE if this cluster contains values that define the width of the eye opening. If width is FALSE, crossing level, left, and right contain default data. crossing level specifies the voltage at which the eye width measurement occurs. left is the lower time value of the eye opening. right is the upper time value of the eye opening. 2D histogram is a 2D array of values that represent the magnitude at locations within the eye diagram.
	mask defines a region in the eye diagram you want to compare with waveform segments. Use the Eye Pattern Mask Definition VI to generate this cluster. time is an array of time values at which mask boundaries intersect on the x-axis. (time, voltage) values at the same indexes define the mask-boundary intersections. voltage is an array of voltage values at which mask boundaries intersect on the y-axis. (time, voltage) values at the same indexes define the mask-boundary intersections. upper limit specifies the upper boundary of the mask you want to apply to voltage values to determine whether the signal falls in the mask. lower limit specifies the lower boundary of the mask you want to apply to voltage values to determine whether the signal falls in the mask.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	plot height/width, if TRUE, specifies you want to plot lines that represent the minimum height and width of the eye opening in the eye diagram. If plot height/width is TRUE but the values of height or width in the eye diagram data cluster are FALSE, this VI runs normally but does not plot height or width lines.
	eye diagram returns an array of values you can wire to an eye diagram to plot the waveform segments. This array corresponds to the 2D histogram array, but the values in eye diagram are scaled to fall between 0 and 1. The numbers in the array represent the intensity of the plot in locations within the eye diagram. The indexes of the elements in the 2D array set the plot locations for the values.
	x scale returns offset and multiplier values you can use to scale the eye diagram. You can use this cluster with the Offset and Multiplier property to set the offset and multiplier of the x-axis in the eye diagram. Offset is the amount by which to offset the origin of the chart or graph on the x-axis. This VI returns the value of t min as the Offset. Multiplier returns the multiplier, or interval, for scaling data using (deltaX)*X + X0.
	y scale returns offset and multiplier values you can use to scale the eye diagram. You can use this cluster with the Offset and Multiplier property to set the offset and multiplier of the y-axis in the eye diagram. Offset is the amount by which to offset the origin of the chart or graph on the y-axis. This VI returns the value of v min as the Offset. Multiplier returns the multiplier, or interval, for scaling data using (deltaY)*Y + Y0.
	error out contains error information. This output provides standard error out functionality.

Eye Diagram Support Details

Before you use the Eye Diagram Support VI, use the Eye Data Generation VI and other Eye Diagram Measurements VIs to construct the eye diagram data. The following block diagram illustrates a common workflow for the Eye Diagram Measurements VIs, including how to set the scale offset and multiplier of the eye diagram.

Examples

Refer to the following VIs for examples of using the Eye Diagram Support VI:

• Basic Eye Diagram VI: labview\examples\Jitter Analysis\Eye Diagram Measurements
• Mask and Limit Test VI: labview\examples\Jitter Analysis\Eye Diagram Measurements