声级校准器的设计

文档编号:DZXX142  文档字数:10241,页数:35

摘要
 随着人们对环境保护的重视，噪声研究在人们生活中有着越来越重要的地位。这时人们就开始生产出声级计，声级计是用来测量环境噪声大小的仪器。而本课题将要研究的是声级校准器，该仪器是一种能在一个或几个频率点上产生一个或几个恒定声压的声源。它用来校准测试传声器、声级计及其他声学测量仪器的绝对声压灵敏度，有时候还将它作为声测量装置的一部分。
 本文档主要通过硬件和软件两个部分介绍带声负反馈的声级校准器的工作原理、主要的性能特点。在原有声级校准器的基础上加入了对输出声音的反馈和调整。原有声级校准器只能输出单一声信号，而本文档介绍的带声负反馈的声级校准器只能产生94 dB声压信号外，还可以产生114 dB（或104 dB）几种声压级。因为单片机能对反馈的声信号做出调节，所以带声负反馈的声级校准器输出的声信号的稳定度也比其他声级校准器好。

关键词： 声校准器、负反馈、声压级
ABSTRACT
 With the enhanced awareness of environmental protection, noise research has become an increasingly important position in people's living. Then people began to produce a sound level meter, an instrument which is used to measure noise level. This subject is to study an instrument called the sound level calibrator that can generate one or more constant pressure of the sound source in one frequency point or a few. It is used to calibrate the absolute acoustic sound pressure sensitivity of the test microphone, sound level meter and other measuring instruments, and sometimes it is also be a part of the sound measuring devices.
 This paper introduces the working principle and the main performance characteristics of the sound level calibrator with negative feedback. It has added the feedback and adjustment of the output based on the original sound level calibrator which can only output a single sound signal. The sound level calibrator with negative feedback in this paper not only can generate 94 dB sound pressure, but also can produce several sound pressure level of 114 dB (or 104 dB). Since the MCU can adjust the feedback sound signal, the stability of the sound signal of the sound level calibrator with negative feedback is better than others.

Keywords: Sound Calibrator，Negative Feedback，Sound Pressure Level
 
 目录

摘要 I
ABSTRACT II
第1章 引言 1
1.1 研究背景 1
1.2国内外现状 1
1.3 研究内容 3
第2章 系统硬件设计 4
2.1  硬件总体框图 4
2.2  系统主要芯片 5
2.3  单片机AT89C2051对电路的控制 11
2.4  A/D转化和D/A转化模块 13
第3章 系统软件设计 16
3.1 概述 16
3.2 程序流程图 16
3.3 系统主要子程序 17
第4章 系统调试 23
第5章 系统设计总结 24
5.1 本文档的主要结论 24
5.2 需进一步研究的问题 24
致谢 25
参考文献 26
附录1  系统总体电路图 27
附录2  实物图 29
附录3  元器件清单 30

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