提出了一种基于超声波测距模块HC-SR04的时差法测量声速的软硬件实现方法,并介绍了相应的硬件模块信号处理流程和测量程序运行流程.本方法可通过精确测量已知距离的声传播时间计算声速.利用所设计的实验装置,实际测量了空气中不同温度下多组声传播速度,测量结果与理论值的最大相对误差仅为0.6％,从而证明了本方法的可行性和合理性.与传统的共振干涉法、相位比较法等声速测量方法相比,本文方法具有实时性高、成本低、结构简单和精度高等优点.%This paper proposes a time-difference method based on HC-SR04,an ultrasonic ranging module,to measure acoustic velocity,and introduces the signal process hardware module and the measuring program running process.The proposed method can calculate the speed of sound by accurately measuring the acoustic propagation time at a known distance.In the experiment,the propagation speeds of ultrasonic waves at different temperatures were obtained through the devices designed for this study.The maximum relative error between the measured results and the theoretical value was only 0.6％,which proved the feasibility and rationality of the proposed method.Compared with the traditional measuring methods such as resonance interferometry and phase-comparison method,the proposed one is of high real-time performance,low cost,simple structure,and high precision.
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