本技术规范描述了在使用标准程序在水中进行的相关声学测量可能伴随着显著的有限振幅效应的情况下，允许计算“衰减”声学量的方法。 本技术规范规定: -有限振幅声学效应产生的水中声学测量适用范围的一般概念； -一种确保在准线性条件下进行测量的方法，以最小化有限的- 振幅效应； -适用于建立准线性条件的声学量的定义； -作为准线性条件上限的声量阈值； -一种在水中非线性传播条件下估计衰减声量的方法。

This Technical Specification describes means to allow "attenuated" acoustic quantities to be calculated under conditions where the associated acoustic measurements, made in water using standard procedures, may be accompanied by significant finite-amplitude effects. This Technical Specification establishes: - the general concept of the limits of applicability of acoustic measurements in water resulting from finite-amplitude acoustic effects; - a method to ensure that measurements are made under quasi-linear conditions in order to minimise finite-amplitude effects; - the definition of an acoustic quantity appropriate for establishing quasi-linear conditions; - a threshold value for the acoustic quantity as an upper limit for quasi-linear conditions; - a method for the estimation of attenuated acoustic quantities under conditions of nonlinear propagation in water.