Strong-scintillation-statistics deterioration due to detector saturation

Fractional moments for processing data from low dynamics acquisition systems in laser atmospheric scintillation

“…In atmospheric optical scintillation measurements, the effect of the nonlinearity of the detector apparatus on the intensity moments was theoretically investigated for different types of intensity PDFs such as lognormal [4], LnME and K [2] or Furutzu [1] distributions. By assuming that the detector answer is linear up to a given saturation value IDS (Fig.1), it was shown that the difference between the nth moment of the intensity, I,of a generic distribution p(I):…”

“…Low dynamics acquisition systems are not suitable for measuring fluctuating signals, especially in the case of strong fluctuations arising in optical propagation through the atmosphere [1]. Low dynamics effect is a truncation of strong fluctuations with the consequence of underestimating the moments [2].…”

“…In the extreme case and by assuming a lognormal probability density function (PDF) it was shown [4] that an 8 bit system can underestimate the intensity variance of a factor up to two. If higher order moments are to be measured, this effect dramatically increases [1,2] also for other distributions commonly used in scintillation statistics. Let us note that a large uncertainty on the variance estimation prevents a correct comparison between any theoretical PDF and experimental data.…”