[time-nuts] Understanding Oliver Collins Paper "Design of Low Jitter Hard Limiters"

raj_sodhi at agilent.com raj_sodhi at agilent.com
Tue Aug 21 16:50:43 UTC 2012


Hello everyone,

I am new to this forum.  
It looks like a lively discussion on various topics.  

A colleague of mine here at Agilent pointed me to this paper entitled "The Design of Low Jitter Hard Limiters" by Oliver Collins. In Bruce Griffiths' precision time in frequency webpage, this paper is described as "seminal."
(http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html)

Since I'm trying to create a limiter that will accept frequencies ranging from 1 MHz to 100 MHz, I thought it would be good to understand the conclusions of this paper (if not the mathematics as well).  The mathematics turned out to be quite challenging to decode. Has someone on this forum unraveled the equations? It appears Collins has recommendations on the bandwidth and gain of a jitter minimizing limiter, and then extends this analysis to provide the bandwidth and gain of a cascade of limiters.  But the application is still fuzzy.  In figure 5, he shows a graph showing the dependence of jitter on crossing time.  Is the crossing time (implied by equations 7) considered a design parameter one can vary? Also, on figure 4, the "k" parameter has been varied to show the rising waveform as a function of "k".  The threshold is always assumed to be 0.5.  So could "k" be related to "tau", the time constant of the RC filter?

Thanks in advance for all your help.

Yours

Raj






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