明渠液位声学测量及嵌入式DSP实现方法研究

发布时间：2018-08-14 18:29

【摘要】：本论文主要研究了超声波明渠液位的测量方法。设计并实现了基于嵌入式DSP的软件和硬件系统。鉴于目前明渠液位测量的的特点和不足之处,本文研究了利用超声波信号对明渠液位进行非接触式测量的方法。通过声阻抗变换的方法提高超声波在空气介质中的传播效率,并利用匹配滤波的方法提高远距离液面反射回波的信噪比,在增加声波作用距离的同时提高了回波时间的测量精度。本论文主要有以下三个方面: 1.论文详细介绍了超声波明渠液位测量的原理和方法,分析了影响超声波明渠液位测量精度和测量量程的因素。采用温度补偿法修正了声速变化带来的误差,利用声阻抗变换原理和匹配滤波的方法提高了超声波回波信号的信噪比。 2.设计了基于嵌入式DSP为核心的软件及硬件系统。硬件部分设计了超声波信号的发射和接收电路、回波信号采集电路以及温度测量电路等,软件部分将信号处理算法在DSP系统上进行了实现。设计了系统与中心站之间的通信协议,实现了测量数据的存储、读取功能。 3.实验研究工作,通过实验验证本文所采用的方法及其实现的系统。
[Abstract]:In this paper, the measurement method of ultrasonic liquid level in open channel is studied. The software and hardware system based on embedded DSP is designed and implemented. In view of the characteristics and shortcomings of open channel liquid level measurement at present, this paper studies the method of non-contact measurement of open channel liquid level using ultrasonic signal. The acoustic impedance transform method is used to improve the propagation efficiency of ultrasonic wave in air medium, and the signal to noise ratio (SNR) of the echo reflected from a long distance liquid surface is improved by using the method of matched filter. The measurement accuracy of echo time is improved at the same time as increasing the range of acoustic wave action. This paper mainly has the following three aspects: 1. In this paper, the principle and method of ultrasonic liquid level measurement in open channel are introduced in detail, and the factors influencing the measurement accuracy and measurement range of ultrasonic open channel liquid level are analyzed. The error caused by the change of sound velocity is corrected by temperature compensation method, and the signal-to-noise ratio of ultrasonic echo signal is improved by using the principle of acoustic impedance transform and the method of matched filter. 2. The software and hardware system based on embedded DSP is designed. In the hardware part, the ultrasonic signal transmitting and receiving circuit, the echo signal collecting circuit and the temperature measuring circuit are designed. In the software part, the signal processing algorithm is implemented on the DSP system. The communication protocol between the system and the central station is designed, and the storage and reading function of the measurement data is realized. The method and the system are verified by experiment.
【学位授予单位】：沈阳航空航天大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP274.53;TP368.1

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