Teledyne Lecroy, Inc.

Lecroy Corporation

Martin T Miller

Thierry Campiche

A method and apparatus for generating a probability density function eye are provided. The method preferably includes the steps of acquiring an input waveform, performing a clock data recovery in accordance with the input waveform to determine one or more expected transition times and defining a plurality of unit intervals of the input waveform in accordance with the one or more expected transition times. One or more values of one or more data points may then be determined in accordance with the input waveform in accordance with the one or more expected transition times, and a category for each unit interval in accordance with its state and its position within the input waveform may also be determined. One or more histograms may then be generated for the determined one or more values for each category of unit intervals.

Noise analysis to reveal jitter and crosstalk's effect on signal integrity

A system for estimating bit error rates (BER) may include using a normalization factor that scales a BER to substantially normalize a Q-scale for a distribution under analysis. A normalization factor may be selected, for example, to provide a best linear fit for both right and left sides of a cumulative distribution function (CDF). In some examples, the normalized Q-scale algorithm may identify means and probabilistic amplitude(s) of Gaussian jitter contributors in the dominant extreme behavior on both sides of the distribution. For such contributors, means may be obtained from intercepts of both sides of the CDF(Qnorm(BER) with the Q(BER)=0 axis, standard deviations (sigmas) may be obtained from reciprocals of slopes of best linear fits, and amplitudes may be obtained directly from the normalization factors. In an illustrative example, a normalized Q-scale algorithm may be used to accurately predict bit error rates for sampled repeating or non-repeating data patterns.

Estimating bit error rate performance of signals

A waveform processing system performs operations that may include identifying a location of a specified bit pattern within a coherently sampled repeating pattern input signal. In some examples, multiple periods of a repeating pattern signal are acquired using coherent sampling techniques such as, for example, coherent interleaved sampling (CIS). In such examples, the sampled waveform may be converted to a binary pattern that can be searched to locate a match to a predetermined or user-specified bit pattern. In one illustrative example, the identified location may be used to display the sampled waveform. In another example, the identified location may be used to measure pattern-dependent jitter of the sampled waveform.

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Martin T Miller