Teledyne LeCroy SDA III-CompleteLinQ - Manual (Page 57)

Operator's Manual
Crosstalk Measurements
Crosstalk Analysis
Crosstalk Analysis is part of the SDAIII-Crosstalk, SDAIII-CrossLinQ and and SDAII-CompleteLinQ prod-
ucts. The dialog is accessed from the Crosstalk button on the main SDA Dialog.
The Crosstalk Eye shows the probabilistic extent of noise both inside and outside the eye, quickly show-
ing the impact of excessive noise that is not possible to see in a traditional eye diagram. Inside the eye,
the analysis is identical as for the IsoBER that can be added to the Eye diagram (see
Eye Diagram Con-
figuration Dialog .)
Crosstalk Eye Algorithm
The crosstalk eye is formed using the following algorithm:
1. Perform pattern analysis to allow the identification of each bit in the pattern. This allows the deter-
mination of all distinct trajectories the signal path can take. For example, a PRBS7 pattern has 127
bits, and 127 trajectories.
2. At 12 positions across the unit interval, calculate histograms of the signal amplitude for each bit in
the pattern.
3. Perform dual-Dirac analysis for each histogram to extrapolate the tails.
4. Integrate from the outside to the center of the the histograms to form CDFs.
5. Combine histograms for each of the 12 positions, forming 2 histograms at each position, one for the
0 state and one for the 1 state
6. For the selected BER values (as determined by the users selections for from, to and step), output the
voltage@BER on both sides of the CDF.
7. Connect the points corresponding to constant BER to form contour plots.
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