Analysis of the Light Emission Signals Based on Autocorrelation Function Calculation

Autocorrelation function is employed to process the light emission signals obtained by PMT, which present the microdischarges igniting in dielectric barrier discharge system. In experiments, signals of different sizes area are measured. With increasing measured size, the signals changes and the number of microdischarges increase. However, the primary signals are coarse and disorder in time series, from which it can not be seen any influence of this microdischarge on the following one. To find the correlation between microdischarges at this time and the following ones, autocorrelation functions of the primary signals are calculated. It is found that with smaller measured area size, the number of microdischarges is smaller and the correlation coefficient fluctuates around 0. This indicates that the microdischarges at this time and the following one are weak correlated. With the measured area size increasing, i.e. the collective microdischarges number increasing, the autocorrelation coefficient increases, which indicates that the correlation degree between the microdischarges at this time and the following ones increases. As the collection of microdischarges in the discharge region, the current presents quasiperiodic property. The results show that the autocorrelation function processing is very useful to investigation on discharge mechanism.