Analysis of statistical characteristics of signals and noises in hydroacoustic communication channels

In the course of distribution of the hydroacoustic signal the structure undergoes some changes, which can be divided into amplitude and phase. Speaking about the change of the amplitude, it is necessary to consider the change of the signal level with increase in distance from the source and fluctuation of the signal level because of the influence of the multipath distribution of the waves and casual changes of transmission factor of the medium. Change of the level with increase in distance from the source of the signal is connected with expansion of the border and various losses. The analysis of the measurements of the characteristics of hydroacoustic signals showed that the corresponding casual processes can be described on the basis of normal frequently met distribution and co-related distributions: Rayleigh, Rayleigh–Rice and lognormal. By the results of the analysis a model of a hydroacoustic communication channel, in which noises have some kind of additive noise with the function of density of probabilities close to the function of density of probabilities of Gaussian process, is offered. Fluctuations of the level and the signal phase are shown slightly, no more than 20% of average value, their speed is significantly lower than transmission speed. The results of the analysis can find their application while creating the systems of hydroacoustic telemetry.