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Random Jitter Measurement Technique

IP.com Disclosure Number: IPCOM000100813D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 32K

Publishing Venue

IBM

Related People

Boerstler, DW: AUTHOR

Abstract

Disclosed is a technique for measuring Gaussian jitter statistics using a standard oscilloscope. Using a conventional scope with a delayed time base capability, the signal can be displayed simultaneously with a delayed version of the same signal. As the delay is gradually increased from its minimum value, a region of uniform brightness (one mode) but of decreasing magnitude will be observed on the display. Once the delay between the two waveforms exceeds exactly 2 times the standard deviation of the normal distribution, a dark band will appear to separate the two bright peaks of the individual traces; this is due to the unique property of summation which two delayed but identical normal distributions posses (see the figure).

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Random Jitter Measurement Technique

       Disclosed is a technique for measuring Gaussian jitter
statistics using a standard oscilloscope.  Using a conventional scope
with a delayed time base capability, the signal can be displayed
simultaneously with a delayed version of the same signal.  As the
delay is gradually increased from its minimum value, a region of
uniform brightness (one mode) but of decreasing magnitude will be
observed on the display.  Once the delay between the two waveforms
exceeds exactly 2 times the standard deviation of the normal
distribution, a dark band will appear to separate the two bright
peaks of the individual traces; this is due to the unique property of
summation which two delayed but identical normal distributions posses
(see the figure). Simply measuring the delay for which the bimodal
character begins and dividing by two gives the standard deviation of
the jitter.