Teledyne LeCroy SDA III-CompleteLinQ - Manual (Page 40)

SDAIII-CompleteLinQ Software
Jitter Histogram
Update the TIE histogram and the Rj+BUj histogram with the values in the TIETrend and the RjBUjTrend,
respectively. For multiple input waveforms, the histogram continues to accumulate until the Clear
Sweeps Front Panel button is pressed.
Jitter Parameters
The fit extrapolation for the NQ-scale model can be shown on the histogram for the NQ-scale model.
The Rj+BUj jitter distribution with the analytical tail extrapolations is then convolved with the DDj dis-
tribution (found during the Pattern Analysis Step) to create the total jitter distribution. This is integrated
to give the jitter CDF. The jitter time at which the CDF crosses the point corresponding to the Bit error
rate of interest (usually 10-12) is calculated for each side of the distribution. The difference of those 2
values is Tj(BER).
The Dual-Dirac model is fit to the extrapolated CDF to yield the final Dj(d-d) and Rj in the case of the NQ-
Scale and Rj+Dj CDF Fit techniques. For the Spectral Rj Direct technique, Rj is forced to Rj(sp) and Dj(d-d)
is determined from the Dual-Dirac constraint.
The jitter parameters explained here are independent of the jitter model selected because they are deter-
mined before the final histogram analysis.
l
ISI is the larger of the range (max-min) of the 2 subsets of the DDJ histogram for neg-
ative edges or positive edges.
l
DCD is the difference in the means of the histograms for the positive and negative
edges.
l
DDj is the range (max-min) of the DDj distribution for both positive and negative
edges (and includes the DCD effect).
l
Pj is the peak-to-peak value of all the periodic jitter obtained from the IFFT of the
peaks.
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