Eye Pattern Limit Test VI

Owning Palette: Eye Diagram Measurements VIs

Requires: Jitter Analysis Toolkit

Applies a mask to an eye diagram to perform limit testing on unit intervals in the diagram. Wire data to the waveform input to determine the polymorphic instance to use or manually select the instance.

Use the Eye Data Generation VI to generate the eye diagram data to which you want to apply the mask. Use the Eye Pattern Mask Definition VI to define the mask you want to apply to the eye diagram. Refer to the Details section of this topic for more information about using this VI with the rest of the Eye Diagram Measurements VIs.

Details  Example

Eye Pattern Limit Test (DBL)

This instance operates on the waveform data type when the Y data values are double-precision, floating-point numeric values. Use the I8 instance of this VI with integer data to reduce the size of the data and the memory usage.

	waveform is the waveform to measure. t0 specifies the start time of the waveform. dt specifies the time interval in seconds between data points in the waveform. Y specifies the data values of the waveform.
	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.
	failed returns the number of samples in the waveform that fall inside the mask region or that violate the upper limit or lower limit you specify.
	total number returns the total number of samples in the waveform.
	error out contains error information. This output provides standard error out functionality.

Eye Pattern Limit Test (I8)

This instance operates on the waveform data type when the Y data values are 8-bit signed integers.

	waveform is the waveform to measure. t0 specifies the start time of the waveform. dt specifies the time interval in seconds between data points in the waveform. Y specifies the data values of the waveform.
	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.
	failed returns the number of samples in the waveform that fall inside the mask region or that violate the upper limit or lower limit you specify.
	total number returns the total number of samples in the waveform.
	error out contains error information. This output provides standard error out functionality.

Eye Pattern Limit Test Details

The following block diagram illustrates a common workflow for using this VI to perform limit testing.

Example

Refer to the Mask and Limit Test VI in the labview\examples\Jitter Analysis\Eye Diagram Measurements directory for an example of using the Eye Pattern Limit Test VI.