BASIC AND APPLICATIONAL STUDY OF MOVABLE SOUND SOURCE USING DEMODULATED SOUND BEAM DERIVED FROM AMPLITUDE MODULATED ULTRASONIC SOUND.

本研究旨在支持盲人阅读CRT的工作。所述包括声音的可听声波被投射到墙上，并作为次级声波从被投射点辐射出去。二次声源的空句及其位置与CRT上的可视句相对应。然后，盲人可以通过听觉识别句子和布局。经过两年的研究，本系统的研究成果如下：光束可听声波是通过参数阵列简单形成的。结果表明，静电传感器具有较高的适应性。凹面反射屏具有良好的聚焦特性，是反射屏的最佳选择。找到了可听声束的最佳转换系统。找到了系统的最佳光束控制方法。测量了该二次声源的定位特性，发现与正常声源的定位特性相同。发现了通过听觉把握CRT上句子内容和布局的可能性。

This research aimed to support the blind on work of reading CRT.The beamed audible sound wave including voice is projected on a wall and radiated from projected point as a secondary sound wave.The vacal sentence from secondary sound source and the position are correspond to the visual sentence on the CRT.Then, the blind can recognize the sentense and the layout by their audible sense.The results of two years research about this system are as follows1. The beamed audible sound wave was simply formed by parametric array.2. The high adaptability of a electrostatic transducer was shown.3. The concaved screen was shown to be optimum for the reflecting screen by it's focal characteristics.4. The best converting system for audible sound beam was found.5. The optimum beam controlling method for the sustem was found.6. The characteristics of localization of this secondary sound sources was measured and found to be same to that of normal sound sources.7. The possibility of grasping content and layout of sentence on the CRT by auditory sense was found.