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Channel-to-Channel Skew VI

LabVIEW 2012 Jitter Analysis Toolkit Help

Edition Date: June 2012

Part Number: 373270B-01

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Owning Palette: Timing VIs

Requires: Jitter Analysis Toolkit

Measures the time differences between corresponding level crossings in two waveforms. The difference in times is also known as delay time, or skew.

You can use this VI to measure the response of a signal to a particular stimulus. For example, level crossings A might be the original signal, and level crossings B might be the response signal following a stimulus. You also can use this VI to compare waveforms from two different channels.

Details  

level crossings A contains information about the locations of level crossings in a waveform.

You can use the Level Crossing VI to generate this cluster from a waveform.
t0 specifies the time at which the first sample occurs in the original waveform.
dt specifies the time interval in seconds between the individual samples in the original waveform.
indexes contains the index numbers of the samples in the waveform with values that fall at the crossing level.
slope identifies the direction of the first transition in the waveform.

-1Falling Edge—Specifies the transition is a falling edge, or one with a negative slope.
1Rising Edge (default)—Specifies the transition is a rising edge, or one with a positive slope.
crossing level specifies the value of the waveform at each of the samples in indexes.
level crossings B (ref) contains information about the locations of level crossings in a waveform. level crossings B (ref) serves as the reference against which this VI compares level crossings A. You can use the Level Crossing VI to generate this cluster from a waveform.
t0 specifies the time at which the first sample occurs in the original waveform.
dt specifies the time interval in seconds between the individual samples in the original waveform.
indexes contains the index numbers of the samples in the waveform with values that fall at the crossing level.
slope identifies the direction of the first transition in the waveform.

-1Falling Edge—Specifies the transition is a falling edge, or one with a negative slope.
1Rising Edge (default)—Specifies the transition is a rising edge, or one with a positive slope.
crossing level specifies the value of the waveform at each of the samples in indexes.
offset specifies an amount of time, in seconds, by which to offset the locations of level crossings in level crossings B (ref). Specifying an offset allows you to more accurately match corresponding transitions in level crossings A and level crossings B (ref) when the initial times in the two waveforms are not equal.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
slope specifies the direction of the transitions for which you want to return measurements.

-1Falling Edge—Returns information about falling edges, or those with negative slopes.
0Both—Returns information about both rising and falling edges.
1Rising Edge (default)—Returns information about rising edges, or those with positive slopes.
delay time sequence is an array of the differences, in seconds, between the times at which level crossings occur in level crossings A and the times the corresponding level crossings occur in level crossings B (ref).
delay time timestamps returns timing information about the waveform that allows you to identify the times at which measurements in the corresponding sequence occur.
t0 returns the time at which the first sample occurred in the original waveform.
dt returns the time interval in seconds between the individual samples in the original waveform.
indexes contains the index numbers of all waveform samples that fall on the crossing level in transitions of the direction you specify in slope. This VI returns the index numbers from level crossings A.
error out contains error information. This output provides standard error out functionality.

Channel-to-Channel Skew Details

This VI uses level crossings B (ref) as the reference against which to measure the skew in level crossings A. Thus, when level crossings A occurs after level crossings B (ref), the delay time sequence value is positive. When the opposite is true, the delay time sequence value is negative.


 

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