Research On Ultrasonic Flow Detection Signal Processing Technology

At present,the ultrasonic flow measurement technology has no perfect solution to the problem that the more particles in the fluid,the greater the signal attenuation and viscous fluid velocity field distribution shows a certain difference,therefore,this paper will start from the above problems,and focusing on the ultrasonic flow detection signal processing technology based on the above situation.The accurate measurement of TOF is an important method to accurately measure the flow rate,and accurate calibration of the flow rate is an important prerequisite for high-precision flow detection.This paper mainly starts from the attenuation compensation of ultrasonic signals in the medium,the design of the transceiver signal circuit,and the design of the TOF measurement method.The theoretical analysis,circuit design,experimental analysis and comparison of results are used to study the ultrasonic flow detection signal processing technology.Firstly,based on the traditional time difference method,this paper analyzes the factors affecting ultrasonic flow detection,and obtains an improved Time Difference ultrasonic flow measurement theory.The flow field laws of different states are different.Therefore,we should study the flow field law,and bring the flow rate compensation factor into the flow measurement theory.Secondly,due to the different fluid properties,the degree of attenuation of ultrasonic waves is different.In order to improve the accuracy of ultrasonic flow measurement,this paper analyzes the attenuation theory of ultrasonic waves in detail and designs a variable gain ultrasonic attenuation compensation circuit.This paper focuses on the ultrasonic flow detection hardware system that can be used in experiments.The system consists of an ultrasonic transmitting circuit,an echo signal processing circuit and peripheral circuits.The signal processing part is mainly controlled by ATmega168 single-chip microcomputer.It is equipped with TDC-GP22 high-precision timing chip of Acam Company of Germany to accurately measure the time difference of forward and reverse current.Then,based on the first wave detection function of TDC-GP22,this paper studies and improves the key technology of flow measurement,adds multi-threshold limit,and proposes a multi-threshold based TOF measurement method to make the measurement result more accurate and reliable.At the same time,the software design of the system is introduced,including initialization module,timing module and so on.At the end of the thesis,the experimental verification and data analysis of the signal processing method proposed in this paper are carried out,which verifies the feasibility and accuracy of the method.At the same time,it also points out the direction for the improvement and research in the next step.