一个新的测量空气中声速温变系统

A NEW SYSTEM OF MEASURING THE VELOCITY OF SOUND WITH RESPECT TO TEMPERATURE IN AIR

为了研究空气中声速随温度变化的特性,开发了基于80C196单片机的测量声速的新系统。该系统采用时差法计算声速。利用单片机发射和接收声波,并记录发射和接收的时间差。采用IN4148二极管作为温度传感器,设计了不平衡测温电桥电路。通过在玻璃管身上均匀缠绕电阻丝建立了空气加热模块,可以方便地改变环境温度。编写了基于Visual Basic的计算机与单片机实时通信的软件和制作了操作界面。实验结果表明,该系统能够很精确地测量空气中声速并作出声速随温度变化的特性曲线。该实验已经应用于大学物理实验课堂和电子实训项目。

In order to study the characteristic of the velocity of sound with respect to temperature in air, a new system is developed to measure the velocity of sound based on 80C196 microcontroller. The velocity is calculated by time difference method. The acoustic wave is sent and received by microcontroller and simultaneously the time difference is recorded. An unbalanced Voltmeter bridge is designed to measure temperature using IN4148 diode as a temperature sensor. A air-heating unit is constructed to change the environment temperature easily by resistance wire wrapped around the glass tube. The real-time communication software between the computer and microcontroller is completed. And an operation interface is built. The experiment results show that the new system can precisely measure the sound velocity in air and acquire the real-time curve of relationship between sound velocity and temperature. The system is applied to college physical experiment and electronic training project.