蝙蝠发声声场强度分布测量仿真系统的研究

【作者】 曹晓琳；

【导师】 王双维；

【作者基本信息】 东北师范大学 ， 电路与系统， 2003， 硕士

【摘要】 蝙蝠是翼手目(Chiroptera)动物的统称，是世界上分布最广、进化最成功的哺乳动物类群之一，除南北极以及大洋中过于偏远的荒岛外，地球上各种陆地生态环境都有蝙蝠的分布。在进化的过程中，蝙蝠避开与其他海陆兽类的竞争而飞向天空；在空中，回声定位系统的高度进化使它们避开与鸟类的竞争而占据了独特的生态位----黑暗的夜空。蝙蝠擅长在夜间活动，它们的视觉较差，听觉却异常发达。因为蝙蝠能够有效地利用回声定位，所以在夜间或十分昏暗的环境中也能自由飞翔并准确无误地捕捉猎物。因此对其回声定位系统的研究有着明显的意义。根据调研我们知道，从生态学角度对蝙蝠的叫声研究多集中在对信号本身的时频特性研究。而从声学本身出发看待蝙蝠信号，它的空间三维场强分布是不可忽视的一个特征，有重要的研究价值。国内外在蝙蝠声场强度分布的系统测量与研究方面尚无专门文献对其做出阐述。且由于蝙蝠的叫声是脉冲形式的超声波，因而要求测量系统必须采用专用的数字信号处理设备才能满足测量要求。 基于目前尚无合适专用仪器的情况，拟用TI公司生产的54系列定点DSP芯片TMS320VC5402为核心自行设计一套专用仪器研究蝙蝠声场强度分布。本论文正是对前期尝试性探索工作的总结。整个论文分为六部分。首先，介绍研究蝙蝠回声定位信号的意义，目前的研究手段以及研究成果，提出对其声场测量的学术意义。接着，从声学角度阐述对于蝙蝠声场强度的分布特征的理论预测，从理论角度分析我们在现阶段实验中所要采集蝙蝠信号的特性。然后，对工作中遇到的几个关键问题进行逐一讨论。接下来依次为实验系统硬件、软件的具体讨论。最后为实验结果。通过上述工作我们希望可以对蝙蝠叫声从声场分布角度进行仿真研究，为后续工作打下基础。更多还原

【Abstract】 Bat is the general designation of chiroptera animals. It is a kind of breast-feed mammal which most extensively distributed and most successfullly evolving. Bats distribute in all kinds of land ecology enviroments in the world expect the South Pole, the North Pole and some remote islands which are in oceans. During the evolution bait flys to avoid competitions with other animals which live in ocean or on land. Successful evolution of echolocation system in the sky makes them avoidcompetitions with birds. So thy occupied a special ecological niche-skyof night. Bat is expert in activing during the night. It has a poor sense of sight while an unusual developed sense of hearing. Because of using echolocation effectively they can fly freely and catch edibles accurately during the night or in very dark enviroments. So it is very meaningful to study their echolocation calls in ecology concentrates in researching time-frequency charaters of the signals. But in acoustics the three dimension field intensity distribution in space is an unignorant character of the signal of bat and is very valuble to be researched. There are not any special documents about surveying and studying the three dimensions field intensity distribution in space of bat. Furthermore, the calls of bats are supersonic pulse, so it is very necessary to use special digital signal processing equipments.Because there are no special instruments we plan to design a special instrument to study the soud field intensity distribution of bat. We use fix point DSPs TMS320VC5402 as a core chip which is made by TI. This paper summarizes the work what we have attempted to do. This thesis is consisted of 6 contents. First, we introduces the meaning of studying echolocation, what means have been used by now, accomplishments got by others and pose the meaning of surveying sound field intensity. Secondly, we expounds theory forecast of the sound field intensity distribution of batin acoustics and analysis the character of the signal that we collect at present. Thirdly, we discuss the problems we have met one by one. And then discusses hardware and software of this system in the two later parts. At last we analysis the results of this reseach. We attempt to survey the calls of bat initially by our work and make a foundation for the follow-up work.更多还原