METHOD AND APPARATUS FOR DETERMINING JITTER AND PULSE WIDTH FROM CLOCK SIGNAL COMPARISONS

摘要

A method and apparatus for determining jitter and pulse width from clock signal comparisons provides a low cost and production-integrable mechanism for measuring a clock signal with a reference clock, both of unknown frequency. The measured clock signal is sampled at transitions of a reference clock and the sampled values are collected in a histogram according to a folding of the samples around a timebase which is either swept to detect a minimum jitter for the folded data or is obtained from direct frequency analysis for the sample set. The histogram for the correct estimated period is statistically analyzed to yield the pulse width, which is the difference between the peaks of the probability density function and jitter, which corresponds to width of the density function peaks. Frequency drift is corrected by adjusting the timebase used to fold the data across the sample set.