【作者】 邹嘉宇；

【导师】 侯文生；

【作者基本信息】 重庆大学 ， 生物医学工程， 2008， 硕士

【摘要】 电子耳蜗是一种利用微电子技术使失聪患者恢复听觉的神经电刺激装置,受到临床医学、神经工程及康复工程界学者的高度重视。电子耳蜗的体外语音信号处理电路是其关键组成部分之一,其主要功能是利用声电换能装置将声音信号转化为可以用来刺激人耳听神经的电信号。国内在电子耳蜗研究方面起步较晚,包括体外语音处理电路部分在内的电子耳蜗关键技术有待进一步完善。本课题对电子耳蜗语音处理电路的研究,有助于提高电子耳蜗的国产化水平,造福于2000多万深度耳聋患者,产生巨大的社会效益和经济效益。本课题在分析人体听觉器官生理结构、电子耳蜗语音信号处理及相关关键技术的基础上,设计了电子耳蜗体外语音处理电路。该电路使用数字信号处理器芯片TMS320VC5402构建了语音处理模块,以音频芯片TLV320AIC23设计了语音信号采集模块,采用无线数传芯片nRF2401A设计了信号发射模块,并设计了其它相应外围模块。其中,数字信号处理器作为核心器件,在进行语音信号处理的同时,还通过多通道缓冲串行口、复用主机接口等接口管理控制这些功能模块电路的初始化及其工作状态设定。在硬件设计基础上,本课题提出了一种基于连续间隔采样CIS方案和连续可变斜率增量调制CVSD算法的新型语音信号处理方案,该方案在完成普通CIS方案频带划分及声-电转换功能的同时,能以较小的语音质量损失获取较大的压缩率以便于无线数据的传输。最后在DSP开发代码设计工作站CCS软件环境中,实现了相应的语音信号处理,使处理信号成为能够提供给体内刺激器语音信息的信号。在语音信号采集、处理、发射各功能模块设计的基础上,针对其小体积的要求,对电子耳蜗体外语音处理电路进行了PCB整体布局上的优化设计,使其达到了基本的便携要求。同时,以电子耳蜗语音处理电路中上述功能模块所要求达到的性能指标为依据,设计了相关的测试方案,分析了实验要点,解决了实验过程中的问题,并对测试结果进行了讨论。结果表明:本课题电子耳蜗语音处理电路可以完成对语音信号的采集、对信号进行分组滤波、编码压缩和量化以进行声电映射、打包组帧及无线发送的功能,达到了电子耳蜗语音处理电路功能上的基本要求。更多还原

【Abstract】 Cochlear Implant (CI) is a kind of electrical nerve stimulative device, which uses microelectronics technology to restore hearing in deaf patients. Many scholars of clinical medicine, neural engineering and rehabilitation engineering attach great importance to it. As a key component in CI, the speech signal processing circuit’s function is to convert speech signals into electrical signals which is used to stimulate the person ear auditory nerves. Since the research of CI started late in our country, the CI’s key technologies including the design of speech processing electronic circuit are needed to be further improved. The research of CI’s speech signals processing circuit in this project is helpful to improve the CI’s progress in our country, which will benefit more than 20 million profoundly deaf patients, and will bring tremendous social and economic benefits.On the basis of analysing the physiological structure of human auditory organ, CI’s speech signals processing strategies and some related key technologies, a CI’s speech signals processing scheme had been designed in this project.This project constructed the signal processing circuit by using digital signal processor TMS320VC5402, designed the speech signal acquisition circuit by emploing audio chip TLV320AIC23, set up the signal transmission circuit based on wireless digital transmission chip nRF2401A and designed the other peripheral circuits. In the proposed scheme, as a core, the digital signal processor not only carried on the signal processing, but also managed the peripheral circuits so as to control their initialization and set their estates of tasks via some interfaces such as the multichannel buffered serial port and the host port. On the basic of hardware design, this research proposed a new kind of speech signals processing strategy, which is based on the combination of continuous interleaved sampling strategy and continuously variable slope delta algorithm. The new strategy filtered the signals and implemented the speech-electricity transform, additionly attained high compression ratio when losing little signal quality in order to transmit data wireless conveniently. Finally, the corresponding speech signals processing strategy had been actualized in the DSP’s development environment----code composer studio software, so that the processed signals become the signals which could provide the speech information for the stimulator. Considering the small volume requirement of the CI circuit, the entire layout of the PCB design optimization had been carried on and the circuit eventually achieved the target of portability. Synchronously, according to the requirements of CI’s functional modules, some corresponding testing experimental schemes had been designed. In these schemes, main points had been analysed, questions encountered in these experiments had been solved. Finally, these schemes discussed test results. The results indicated that: this circuit can accomplish the acquisition of speech Signals, the signals filtering, compression and quantification for the speech-electricity mapping, frames packing and wireless transmission. The CI circuit achieved the basic function which the CI’s speech signals processing circuit requested.更多还原