FINE STRUCTURE OF 2F1-F2 ACOUSTIC DISTORTION PRODUCT

人们对2f 1-f2声学失真积（ADP）的兴趣越来越大 用于临床和研究应用。它是高频率的 具体地，它可以在大多数人类和动物受试者中测量， 可客观地用于婴幼儿听力筛查。 然而，其应用的成功受到以下事实的限制： ADP的生成机制仍然没有完全理解。有 关于ADP生成地点的问题，无论是 在单个耳蜗区域内产生，或者多个区域 有助于在耳道中测量的ADP。详细介绍如何 在特定区域内产生的ADP也很差， 明白目前尚不清楚总体ADP是否来自 基本上是单个发电机或从一组发电机连续地 分布在其中贡献被矢量求和的区域内。 本文提出的研究将以一种新的方法探讨这些问题 其中ADP的精细频率结构及其基底- 将检查与膜相关的特性。借助于一个 ADP精细结构的矢量和模型（Sun等人，I994 a，B），四 将进行实验。前两个实验的目的是 检查主要的频率和水平比的影响 ADP精细结构上的色调。这些初步实验将解决 关于ADP发生器的位置和数量的基本问题。为 例如，从2f 1-f2位置的再发射是否有助于 生成ADP精细结构？后两个实验将产生数据 关于噪声掩蔽物对ADP精细结构的影响。 重点将放在ADP精细结构的产生方式。 在ADP精细结构的变化与不同的水平和带宽的 窄带掩蔽器将帮助确定是否存在矢量和机制 参与ADP精细结构的产生，如果是这样，它的关键 带宽这些实验将测试公布的模型，并将 扩展我们对耳声发射的基本知识。

There is growing interest in the 2f1-f2 acoustic distortion product (ADP) for both clinical and research applications. It is highly frequency specific, it can be measured in majority of human and animal subjects, and it can be used objectively for the hearing screening of infants. However, the success of its application is limited by the fact that the generation mechanism for the ADP is still not fully understood. There are questions about the site of generation of the ADP, whether it is generated within a single cochlear region, or whether multiple regions contribute to the ADP measured in the ear canal. Detail about how the resultant ADP is generated within a specific region is also poorly understood. It is not clear whether the overall ADP results from essentially a single generator or from a group of generators continuously distributed within an area wherein contributions are vectorially summed. The study proposed here will investigate these issues with a new approach in which the fine frequency structure of the ADP and its basilar- membrane-related characteristics will be examined. With the aid of a vector sum model of ADP fine structure (Sun et al., I994a,b), four experiments will be conducted. The first two experiments are designed to examine the effects of the frequency and level ratios of the primary tones on the ADP fine structure. These first experiments will address basic issues concerning the site and number of ADP generators. For example, does re-emission from the 2f1-f2 place contribute to the resultant ADP fine structure? The latter two experiments will yield data concerning the effects of noise maskers on the ADP fine structure. Emphasis will be placed on the way the ADP fine structure is generated. Changes in the ADP fine structure with varying level and bandwidth of a narrowband masker will help determine if there is a vector sum mechanism involved in the generation of ADP fine structure, and if so, its critical bandwidth. These experiments will test the published model and will extend our basic knowledge of otacoustic emissions.