Bo-xiong WANG(王伯雄), Jin ZHANG(张金)
State Key Laboratory of Precision Measurement Technology and Inst ruments, Dept. of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084, China
Abstract-Based on the evaluation of advantages and disadvantag es of high-precision digital time interval measuring algorithms, and combined w ith the principle of the typical time-difference ultrasonic flow measurement, t he requirements for the measurement of echo time of flight put forward by the ul trasonic flow measurement are analyzed. A new high-precision time interval meas urement algorithm is presented, which combines the pulse counting method with th e phase delay interpolation. The pulse counting method is used to ensure a large dynamic measuring range, and a double-edge triggering counter is designed to i mprove the accuracy and reduce the counting quantization error. The phase delay interpolation is used to reduce the quantization error of pulse counting for fur ther improving the time measurement resolution. Test data show that the system f or the measurement of the ultrasonic echo time of flight based on this algorithm and implemented on an Field Programmable Gate Array(FPGA) needs a relatiely sh ort time for measurement, and has a measurement error of less than 105 ps.
Key words-ultrasonic flow measurement; time of flight; phase delay interpolation; FPGA
Manuscript Number: 1674-8042(2010)02-0103-05
dio: 10.3969/j.issn.1674-8042.2010.02.01
References
[1]A. E. Stevens, B. R. P. Van, D. S. J. Van, et al, 1989. Time to volt age converter and analog memory for colliding beam detectors. IEEE Jou rnal of Solid-State Circuits, 24(6): 1748-1752.
[2]M. J. Bowman, D. G. Whitehead, 2007. A picosecond timing system. IEEE Transactions on Instrumentation and Measurement, 26(2): 153 -157.
[3]P. K. Chande, P. C. Sharma, 1986. Ultrasonic flow velocity sensor ba sed on picosecond timing system. IEEE Transactions on Industrial Elect ronics, 33(2): 162-165.
[4]R. Szplet, J. Kalisz, R. Szymanowski, 2000. Interpolating time count er with 100 ps resolution on a single FPGA device. IEEE Transactions o n Instrumentation and Measurement, 49(4): 879-883.
[5]Hua Meng, Fei Yan, Ming-wei Li, 2007. New transit-time ultrasonic flowmeter. Instrument Technique and Sensor, (8): 18-20.
[6]Jie Sun, Ji-fei Pan, 2007. Methods of high precision time-interval measurement. Computer Measurement & Control, 15(2): 145-148 .
[7]Jin Zhang, Bo-xiong Wang, Xiu-zhi Luo, et al, 2009. MEMS-based Ul trasonic Flow Measurement. The 8th International Symposium on Test and Measureme nt. Chongqing, p. 1227-1232.
[8]E. Mandard, D. Kouamé, R. Battault, et al, 2005. Transit time ultra sonic flowmeter: Velocity profile estimation. Ultrasonics Symposium. IEEE, p. 76 3-766.
[9]A. Aloisio, P. Branchini, R. Cicalese, et al, 2007. FPGA Implementa tion of a High-resolution Time-to-digital Converter. IEEE Nuclear Science Sym posium Conference, p. 504-507.
[10]Jian-hua Xie, Wei-dong Ye, Yue-feng Han, 2006. Design and applic ation of double edge trigger counter. O. I. Automation, 25(4) : 71-72.
[Full Text View]
