Tool/software:
To understand the overall jitter measurement it is important to understand what jitter is. All system jitter measurements have components of Deterministic Jitter (DJ) and Random Jitter (RJ) that sum to make the Total Jitter (TJ). DJ is the amount of jitter that is certain to the system, it is predictable and repeatable, so no matter how long the system is running the DJ will stay the same. RJ is random and increases exponentially with time. RJ causes all eyes to close if the system is left on forever, but that is not useful to engineers because we do not live forever. So, it is essential that we make a common threshold for the transmitted bits. A common threshold for measurement is 1E12 bits.
Now into the jitter measurements we can take. The first is the Time Interval Error (TIE). The TIE is the amount of time that the actual bit transition strays from the expected position for transition. The TIE can be displayed in a gaussian (normal) distribution histogram.
As the distribution moves further and further from the mean and towards the 3 sigma and -3 sigma regions of the distribution, the number of hits strongly decreases. A useful component of the TIE histogram is that the width of the histogram in ps shows the density of the transition point of the eye diagram.
Notice how the width of the transition point for the eye diagram is the same as the width of the histogram ~40 ps.
Another measurement is the BER bathtub. The bathtub is a visualization tool for the TJ's effect on the eye closure. As the number of bits increases from one, the eye closure increases as RJ increases.
Notice that at 1E12 bits the eye is closed by ~0.8 UI which is 67 ps of closure for 12G SDI.
With these three components of measurement it is possible to visualize the effects of jitter on eye closure. The jitter directly corresponds to the horizontal shrinkage of the eye diagram.
Best Regards,
Nick