Probability Distributions of the Zeros of Random Noise

A complete expression for the probability distribution of the zero crossing periods of filtered random noise is given. The first term of this expression is evaluated and extended to include narrow, symmetrical spectra. The behavior of the frequency function about the second and further half-periods is investigated. Apparatus has been designed and constructed which gives directly the distribution function of the zeros of filtered random noise. Distribution functions corresponding to several filters are shown. Correlation between theoretical and experimental distributions is good.