Development Of Gas Ultrasonic Flowmeter

In this paper, a gas ultrasonic flowmeter with transit-time difference measurement has been designed.DSP is the core of hardware, which controls the whole system to realize sampling of ultrasonic signal, processing of signal data, etc. The corresponding PCB has been maken and debugged.The transmission and receiving of ultrasonic signal are controlled by software, and the recognition of arrived-time is based on wavelet theory. The key to transit-time difference method lies in the determination of arrived-time. In this paper, a new recognition method has formed based on wavelet, which conbines the wavelet transform and Hilbert transform, takes the advantage of wavelet in singularity recognition to calculate the arrived-time. Calculation of groups of sampled data indicates good validity and repeatability.