RESEARCH AND DEVELOPMENT OF PRACTICAL HEARING AIDS FOR TELEPHONIC SPEECH WITH A SMALL NON-LINEAR DISTORTION

为了实现单共振分析型助听器对电话语音的实时处理，我们尝试制作一个小型DSP系统，并以此系统为基础进行研究。单共振分析（SRA）型助听器的语音与其他类型的助听器相比具有较小的非线性失真，但其计算需要比其他类型的助听器更复杂。该研究系统有四个DSP单元来进行实时计算，并包括用于开发助听器算法的硬件。由于一个DSP的能力在最近得到了很大的提高，两个高速DSP（每个60 MFLOPS）被用于构建紧凑型助听器。而且软件已经适应了新的硬件。事实证明，它能够将助听器的体积减少到研究系统的1/20。这个尺寸足够小，可以放置在电话的两侧。在项目的最后部分，DSP的性能得到了很大的改善，可以在不久的将来开发出一种用于电话语音的DSP助听器，用于SRA型助听器的现场测试。同时，针对听障人士的实际测试，也需要改进配套件方案。

To realize the single resonant analysis type hearing aid for telephonic speech by real-time processing, we tried to make a small DSP system, which is based on our system for research. Single resonant analysis (SRA) type hearing aid presents speech sounds with a small nonlinear distortion compared with other types of hearing aid, but it needs more complicated calculations than other types of hearing aids. The system for research has four DSP units to perform real-time calculation, and includes hardware for developing the algorisms for hearing aids. As the ability of one DSP improves very much these days, two DSPs at high speed (60 MFLOPS each) are used to build up compact hearing aid. And the software had fitted to new hardware. It proved to be able to reduce the volume of the hearing aid to 1/20 of research system. This size is small enough to place to the sides of a telephone. In the last part of this project, much improvement in DSP performance was reported, and one DSP hearing aid for telephonic speech can be developed for the field test of SRA type hearing aid near future. And the fitting programs also should be improved for practical tests by hearing impaired person.