Teledyne LeCroy SDA II - Manual (Page 36)

Serial Data Analysis II Software
Jitter Histogram Analysis
Two jitter histograms can be viewed in SDAII, the TIE histogram, which contains all sources of jitter, and
the Rj+BUj histogram, which has the DDj removed.
The integrated histogram or the CDF (cumulative distribution function) can also be viewed. The CDF can
also be displayed in the more standard representation of a bathtub curve. Zoom in on any of the plots
by touching the trace descriptor, and then selecting the zoom tab on the right side dialog. The following
picture shows the Histogram Analysis dialog.
Show Rj+BUj Histogram - Displays Rj+BUj Histogram. Vertical axis is in number of edges in a particular
jitter bin. Horizontal axis is the RjBUj jitter value. Scale is linear. Sometimes it's useful to use the log10
math function to get a log vertical scale to make it easier to view the tails.
Show TIE Histogram - Displays TIE Histogram. Vertical axis is in number of edges in a particular jitter bin.
Horizontal axis is the TIE jitter value. Scale is linear. Sometimes it's useful to use the log10 math function
to get a log vertical scale to make it easier to view the tails.
Show Q-Fit for RjBUj- Plots the histogram in the Q-Scale representation. In the Q-Scale representation,
Gaussian tails result in straight lines whose slope is equal to 1/Rj. Teledyne LeCroy uses a special Q-scale
which we call nQ-Scale or normalized Q-Scale. This allows for Gaussian distributions with variable pop-
ulations or normalizations. Shown with the Q-scale transform is the best straight line fit ( the thin white
line).
Show CDF - Plots the Cumulative Distribution Function for the extrapolated RjBUj histogram convolved
with the DDj histogram.
Show Bathtub - Plots the bathtub (same information as CDF, shown in bathtub format).
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