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Question: Is random jitter (RJ) the same on every
bit of the pattern?
Answer: MJSQ[1] defines
the mathematical quantity RJ, as used in the dual-Dirac jitter model, as being
pattern independent. In reality, the random jitter will frequently vary from
bit to bit. An example might help here: Channel bandwidth effects cause
different bits in a pattern of data to have different rise times or slopes.
Amplitude noise on the signal move the edge by different amounts for
different slopes.
The new Jitter Map option for the BERTScope family provides the
RJRMS needed for MJSQ compliant measurements,
but also has an RJ/bit view giving insight into pattern-related RJ. An example
is here.
[1] 'Fibre Channel – Methodologies for Jitter and Signal
Quality Specification' – MJSQ, T11.2, Project 1316-DT, Rev 14, June 9, 2004. |
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Science Puzzler
Why is it so quiet just after a snowfall? There may
not be as many people or cars outside as usual, but that alone doesn’t
explain such quietness. Where does the energy of the outside noise go?
Why does the snow have to be fresh?
(Click for Answer) |
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Quote of Note
The early bird may get the worm, but the second mouse
gets the cheese.
— Anonymous |
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Guess What?
(Click for answer)
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