Teledyne LeCroy SDA III-CompleteLinQ - Manual (Page 52)

SDAIII-CompleteLinQ Software
Noise Pattern Analysis
The Pattern Analysis dialog provides controls used to set how the noise analysis algorithm determines
the pattern, along with a checkbox to control whether the digital pattern is shown.
Pattern analysis is a key step in the algorithm to determine Tn, Dn and Rn. It is recommended to use a
value of at least 100 for Patt Reps. Note that you do not need to acquire the selected number of reps of
the pattern in each acquisition: the oscilloscope will accumulate iterations over multiple acquisitions, and
keeps track of partial iterations as well.
Pattern analysis may be performed in two ways.
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Repeating Pattern - Indicates that the input waveform is a repeating pattern such as a
PRBS pattern
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Non-Repeating Pattern- The average TIE value is calculated for edges with similar patterns of pre-
ceding N bits. To use this method, clear Repeating Pattern.
NOTE: If the number of iterations specified in the Min Reps selector have not been accumulated when
using Repeating Pattern method, Tn, Rn, Dnall return with --- values showing on the jitter measure table
Show DigPatt - Check this box to display the Dig. Pattern. Touch the Show DigPatt button on the same
dialog for an additional digital representation of the pattern.
NOTE: Having the Digital Pattern and the DDjPlot on the display at the same time is useful for identifying
exactly where in the pattern DDj is found. You can even mark the Show DDj Histogram checkbox to
include a histogram of all of the DDj values.
Show ISIPlot - Check this box to display the ISI Plot. An eye pattern is then shown consisting of the aver-
aged waveform trace from each pattern in the data stream of a specified length. The length can be
adjusted from 3 to 12 bits and the averaging removes the effects of random jitter in the signal. What is
left is an eye diagram with all noise and random jitter removed. All that remains is the Intersymbol Inter-
ference (ISI) and the Duty Cycle Distortion (DCD). A specific pattern may be selected for highlighting on
the ISI Plot.
Find Pattern - Touch this control on both the Pattern Analysis and Pattern dialog and the system auto-
matically finds the pattern for you. The control is disabled on both dialogs when using non-repeating pat-
tern mode.
Length - Touch this control to provide a specific length value.
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