Ultrasonic Doppler Flowmeter Signal Processing Module Design

In the field of flow measurement, ultrasonic flowmeter technology developsrapidly because of its unique advantages, but most of the domestic and internationalstudies have focused on the time-difference method, and the research based on Dopplermethod is relative few, as a result, the Ultrasonic Doppler flowmeter productperformance is generally not high. Therefore, launching an in-depth study on theUltrasonic Doppler flowmeter has practical significance, which is the starting point ofthis paper. Besides, the paper aims to put the ultrasonic measurement techniques to beused in oil drilling projects for overflow monitoring.First of all, the relevant knowledge of ultrasonic flowmeter is briefly introduced inthe introduction of this paper, including the background and classification of ultrasonicflowmeters, and then it describes the advantages and disadvantages of the UltrasonicDoppler flowmeter at home and abroad. After that it makes a theoretical analysis of theUltrasonic Doppler flowmeter, including the Doppler Effect, the principle of flowmeasurement model, the theoretical knowledge about ultrasonic transducer and the fluidvelocity distribution in the tube and so on. Then an overall design philosophy of thesystem is given, and it makes a brief introduction on the working process of theultrasonic Doppler flowmeter, it also analyzes several key issues in the design of thesignal processing module. Next problem is the focus of this project—the hardwarecircuit design and software system design. Hardware circuit mainly includes continuousultrasonic generating circuit、echo signal processing circuit、DSP and peripheral circuitdesign. Echo signal processing module includes the initial echo signal amplificationcircuit, Butterworth bandpass filter circuit, mixer processing circuit and low-pass filtercircuit. The digital signal processing part selects TMS320F28335which is afloating-point DSP chip of TI company as the core, it mainly includes clock circuit, theJTAG interface circuit, power supply circuit, reset circuit and RS232serialcommunication circuit. The software section details the initialization subroutinemodules, DDS sine wave generating subroutine modules, the AD sampling subroutinemodules, data processing subroutine modules, LCD displaying subroutine modules andserial communication subroutine modules.Finally, system debugging and analysis of the collected data show that this systemhas basically reached the expected requirements, it can work steadily, Besides the paperalso points out the direction for further improvement of the system.