SSC profile question

Jenkins, Mike Mike.Jenkins at
Tue Nov 27 14:22:23 PST 2007

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Phy folks,
I have a question regarding the SSC profile to which I cannot find an
answer in the draft spec.  (As usual, my apologies if I've overlooked
something.)  The question is how the profile is measured in practice.  
Measuring clock waveform periods will result in significant noise
superimposed on the longer term frequency.  For example, 0.01UI
instantaneous jitter in one clock cycle is a 10 000 ppm frequency error.
Obviously such data must be filtered, but what is the filter?  An
obvious candidate is the low pass filter defined by 1-JTF, but this
should probably be defined.
For what it's worth, I do not believe there is even a defined
measurement procedure to verify the +/-100 ppm "long-term" frequency
Thanks for any pointers or opinions on this question.

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