Intermittent shot noise generating 1/f fluctuations

Abstract

When the rate of shot noise is controlled by on-off states we speak of intermittent shot noise. The on-off states lead to alternately occurring clusters of events and intermissions, respectively. We derive the power spectrum of the intermittent shot noise by applying the Wiener-Khinchin theorem. Besides reduced shot noise, we obtain excess noise, which depends on the parameters of the on-off states. We calculate the excess noise for power-law distributed on-states; within the scaling region, the excess noise is excellently approximated by C/f^b. The behavior of the slope b and of the amplitude C in dependence of the on-off times is investigated. For large scaling regions we find a preference for a pure 1/f shape. Finally, we regard the variance of events occurring within a time interval. In the presence of 1/f fluctuations, the variance of counts attains extreme values which are accompanied by an extreme property of slope b.