科研之友
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摘要
The purpose of this research is to develop a prospective and original sound transmitted system that applies on localized sound field reconstruction by using ultrasonic wave. Generally speaking, speakers generate sound as well as disturb others without keeping personal privacy. It is uncomfortable to use earphone. Hearing degradation is occurred on the people using earphone for a long period of time. There are many products (such as directional speaker systems and ultrasonic transducer systems) on the markets for sound field reconstruction. But the systems have a disadvantage, which need a large number of speakers. Also, they generate sound along the transmission path. The phenomenon of this research is the sound field can be reconstructed at specific location instead of generating the sound along the transmission path. In this new system, two plane waves of differing frequencies are generated by ultrasonic emitter array, when traveling in the same direction, two new waves, one of which has a frequency equal to the sum of the original two frequencies and the other equals to the difference frequency. For human physiology, human ear can nominally hear sound in the range 20 Hz to 20 kHz. Therefore, only the difference frequency which is in the audible frequency range can be heard. Above all, the purpose of the research is to develop a prospective and original transmitted system that applies on localized sound field reconstruction. The transmitted sound system is based on the nonlinear effects of ultrasound wave and the combination of audible frequencies of sound. Hence, the localized sound field can be generated at the specific area.
- 出版日期2013-10
