| Both industrial production and scientific experimentation cannot go away with realization and control of flow.The ultrasonic flowmeter's operating theory is that when ultrasonic pass the liquid,it carries out the signal reflecting the liquid's flow velocity,and then,the signal will be used to compute the flow. Due to its advantage in accuracy,turndown ratio and no excess pressure drop,the current market for ultrasonic flowmeter technology is growing rapidly in flow measurement. However,the ultrasonic flowmeter develops just some ten years,and has not run in all fields it can be, so it provides many distinct and difficult challenges. That is one reason why this thesis chooses the topic. The system of ultrasonic correlation flowmeter has been designed aiming at solving the current problems. Performance of flowmeter is improved because of using the DSP. At first discrete formula for computing correlation function of two signals has been deduced by using FFT transform and IFFT transform from correlation theory and correctness is validated by virtue of program in MATLAB. Secondly, hardware has been designed, whose core is DSP chip of TMS320VC5402 on the basis of forward formula. High precision is guaranteed because of quick velocity of signal processing of DSP chip. Hardware includes generating and amplifying of ultrasonic,receiving and amplification of signal,data acquisition,Memory, display and DSP; Thirdly software is programmed in CCS according to the hardware. Software includes subprograms of direct digital frequency synthesis,subprogram of analog to digital converter,subprogram of FFT, subprogram of display and main program. Finally Considering the other factors, anti-jamming has been added to the system of hardware and software. By imitating in the laboratory, it is proved that this system is a low cost and high efficiency one, and it's valuable for theory and application study and it is feasible.
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