耳声发射仿真测试系统的设计与实现

发布时间：2018-04-09 01:08

本文选题：耳声发射　切入点：仿真电子耳蜗　出处：《北京交通大学》2015年硕士论文

【摘要】：耳声发射现象及其临床应用是儿科研究的重要进展,此种检测手段可使用的人群范围较广,从新生儿的听力筛选、到急救情况下成人的监护,适用于各年龄段的人群。从2010年开始,国家制定法律,强制要求新生儿必须于48小时内进行耳声发射的听力检测。耳声发射检测已经成为国内外临床上广泛用于的检测听力的方法。但是,耳声发射检测仪器的校准始终是难题,只有针对耳声发射检测仪部分部件的校准工作,至今未见报道耳声发射检测仪整体功能的相关解决方案。本论文设计并实现的耳声发射仿真测试系统,针对目前对耳声发射检测仪无校准方案这一问题,能完成检测耳声发射检测仪的功能。本文的主要工作如下： (1)系统在硬件方面,采用TI公司的TMS320F2812作为核心芯片和系统的主控制器,将TLV320AIC23B这个高速高分辨率的音频处理芯片,配合AD620高性能放大器芯片,实现了系统的主要信号处理模块;系统采用锂电池供电,采用便携式仪器的省电供电方案,通过电池转换芯片为系统各部件提供不同的工作电压；系统还具有存储功能,也能与计算机通信,还可直接连接打印机对测试结果进行打印,直接提供检测结果。 (2)系统在软件方面,模拟现实情况,预置了覆盖人耳耳声发射信号频率范围的周期性信号,用DSP实现系统所需的发射信号,对接收信号采用时域加窗避免耳声发射信号潜伏期,采用相干平均的方法降低底噪的影响提高接收信号的信噪比。系统采用成熟的信号处理技术对声音信号进行处理,能获得预期的结果。 (3)在测试环境方便,首先是模拟人耳耳道的环境,根据IEC-60318标准制作了2CC仿真耳耦合腔,完全模拟声音的耳道内的传播环境,使系统的工作在仿真人耳道的环境中进行；另外,采用双层板结构的方式制作了消音箱,从外至内依次为不锈钢板、聚酯胺吸声棉、空气夹层,不锈钢板和聚氨酯吸声棉,使其达到在室内噪声为40dBSPL时,将消音箱内的噪声降低至35dBSPL左右的效果。通过以上,完成了耳声发射仿真测试系统的设计与制作,达到了预期的效果,实验结果表明本设计能够有效的检测和校准耳声发射检测仪。
[Abstract]:Otoacoustic emission and its clinical application are important advances in pediatric research. This method can be used in a wide range of people, from neonatal hearing screening to adult care in emergency situations, suitable for all ages.Since 2010, the country has enacted laws that require newborns to undergo otoacoustic emission hearing tests within 48 hours.Otoacoustic emission (OAE) detection has become a widely used method for hearing detection in clinic at home and abroad.However, the calibration of otoacoustic emission testing instruments is always a difficult problem. Only for the calibration of some parts of the otoacoustic emission detector, there is no relevant solution to report the overall function of the otoacoustic emission detector.The otoacoustic emission simulation testing system designed and implemented in this paper can accomplish the function of the otoacoustic emission testing instrument, aiming at the problem that there is no calibration scheme for the otoacoustic emission detector at present.The main work of this paper is as follows:In the aspect of hardware, the TMS320F2812 of TI Company is used as the core chip and the main controller of the system. The TLV320AIC23B, which is a high speed and high resolution audio processing chip, is combined with the AD620 high performance amplifier chip to realize the main signal processing module of the system.The system uses lithium battery to supply power, adopts the power saving scheme of portable instrument, provides different working voltage for each part of the system through battery conversion chip, and also has the function of storage, and can also communicate with computer.Can also be directly connected to the printer to print the test results, directly provide the test results.In software, the system simulates the reality and presets the periodic signal covering the frequency range of the otoacoustic emission signal. The system uses DSP to realize the needed emission signal, and the time domain window is used to avoid the latent period of the otoacoustic emission signal, and the time domain window is used to avoid the latent period of the otoacoustic emission signal.The coherent averaging method is used to reduce the influence of background noise to improve the signal-to-noise ratio of the received signal.The system uses mature signal processing technology to process the sound signal, and the expected results are obtained.3) in the test environment, the first is to simulate the human ear canal environment. According to the IEC-60318 standard, the 2CC simulation ear coupling cavity is made to simulate the sound propagation environment in the ear canal completely, so that the system can work in the human ear canal environment; in addition, the system can be used to simulate the human ear canal.In this paper, a double layer panel structure is used to fabricate the sound suppression box. The order from outside to inside is stainless steel plate, polyester amine absorbent cotton, air interlayer, stainless steel plate and polyurethane sound absorber cotton, so that the sound absorption box can reach the range of indoor noise of 40dBSPL.Reduce the noise in the muffler box to the effect of 35dBSPL.Through the above, the design and manufacture of otoacoustic emission simulation testing system have been completed, and the expected effect has been achieved. The experimental results show that the design can effectively detect and calibrate the otoacoustic emission detector.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R764;TN912.2

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