A Statistical Model for the Fluctuation of Sound Transmission in the Sea.

摘要

The fluctuations in amplitude of a narrow-band signal in the sea obey a simple mathematical relationship. Under the premise that fluctuations are caused by random multi-path contamination of an otherwise steady signal,it follows that they are distributed in amplitude in the same way as is the resultant of a constant vector plus the random vector representing the sum of the various multipath contributions. This distribution function was obtained many years ago by S. O. Rice and is sometimes called the Rician distribution. It can be represented by a family of curves having as a parameter the relative power in the multipath additions. In this report the validity of this distribution for real signals in the sea is demonstrated by examples of fluctuations observed under a wide range of frequencies and propagation conditions. If it is indeed valid,the model permits one to predict the fluctuations of a transmitted signal in the sea around its mean intensity better,in many circumstances,than one can predict the mean intensity itself.