【作者】 么启；

【导师】 刘纪元；

【作者基本信息】 沈阳航空航天大学 ， 信号与信息处理， 2012， 硕士

【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。更多还原

【Abstract】 This paper mainly studies the method of ultrasonic open-channel level measurement, and designs software and hardware system based on embedded DSP system. In view of the characteristic and deficiency of open-channel level measurement, this paper studies non-contact open-channel level measurement method in use of ultrasonic signal.The method of acoustic impedance transform is used to improve the transmission efficiency of ultrasonic wave in the air, and the method of matched filter is used to improve signal to noise of remote liquid surface reflection echo, increasing the action distance of sound wave while the measuring precision of echo time is improved.The article consists of three parts:1. The article introduces the principle and method of open-channel level measurement in detail, and analyzes the influencing factors of measurement precision and range. The method of temperature compensation is employed to fix the error caused by the change of sound velocity, and the method of acoustic impedance transform and Matched filter is employed to improve the signal to noise ratio of echo.2. The article designs software and hardware system based on embedded DSP system. Hardware system includes the circuit of ultrasonic signal emitting and receiving, acquisition echo, temperature measurement, etc. Software system realizes the signal processing algorithm on DSP. Communication protocol is defined between the system equipments and center station, realizing the storaging and reading of the measurement data.3. The work of experimental study, through the experiments, the method mentioned above is proved and the system is realized.更多还原