Keywords
time-of-flight interval
modulation
correction
Abstract
This paper describes the main problems that appear during the measurement of time-of-flight intervals in acoustic tomography, which are related to the influence of noise and with a limited slew rate of the signal amplitude envelope. Analysis of possibilities of using linear modulation of period of the acoustic pulses with the aim of improving the accuracy of the time-of-flight measurement in noise conditions and influence of limited slew rate envelope is presented in this paper. The proposed method of correction of directly measured time interval is based on the additional measurement of duration the given number of half periods of received signal when the signal envelope stabilizes at a sufficient level. Efficiency of was studied by simulation method.
References
[2] Dorozhovets M., Baran А, Kusij A., Stadnyk В.: Mathematical Aspects of Measurement of Temperature Fields in Gases and Flames. VDI/VDE-Gesselschaf Mess-und Automatisierungstechnik, "Temperatur '92", Dusseldorf, 1992, pp.249- 252.
[3] Doster M., Hentshel G.: Die akustische Gastemperaturmestechnik ein automatisches, beruhrungsloses Mesverfahren. VDI/VDE- Gesselschaft Mess-und Automatisierungstechnik, “Temperatur ‘92”, Dusseldorf, 1992, pp.169-177.
[4] Dorozhovets M., Kouzii A., Stadnyk B.: The Measurement of Temperature Field by Ultrasonic Computer Tomography Methods. IMEKO TC-4, International Symposium On Intelligent Instrumentation For Remote And On-Site Measurements, Brussels, 1993.pp 159-163.
[5] Schwarz A.: Acoustic measurement of temperature and velocity fields in furnaces. Tomographic techniques. Proceeding ECAPT-92, Manchester, UK, 3/1992.
[6] Prospekt firmy Codel Stack Emission Monitoring. The Total Concept. Combustion Development Ltd. Bakewell, Derbyshire, UK, 1994.
[7] Dorozhovets M., Basarab Horwath I.: Measurement of the Temperature Distribution in Fluid Using Ultrasonic Tomography. Institute of Electrical and Electronic Engineers. IEEE Ultrasonic Symposium Proceedings, 1994Vol. 3, pp. 1891-1894.
[8] Barth M.: Akustische Tomographie zur zeitgleichen Erfassung von Temperaturund Strömungsfeldern, Leipzig, 2009.
[9] Mayer A.V.: On Acoustic Pyrometer. Philosophical Magazine, 1873, 45, pp.18-22.
[10] Honarvar F., Sheikhzadeh H., Moles M., Sinclair A. N.: Improving the timeresolution and signal-to-noise ratio of ultrasonic NDE signals,” Ultrasonics, vol. 41, 2004, pp. 755-763.
[11] Svilainis L., Dumbrava V., Chaziachmetovas A., Jurkstas P., Aleksandrovas A.: Technique for the Performance Evaluation of the Ultrasonic Preamplifier Input Protection Circuits. Procedings of the 2015 IEEE 8th International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS). Volume 1, 2015, pp. 102-107.
[12] Dorozhovets M.: Application of hyperbolic-frequency modulated pulses to improve the accuracy of measurement of time-of-flight intervals in the acoustic tomography system, Automation, Measurement and Control, Lviv Polytechnic National University, N 356, 1998, p. 15 -21, Lviv, (in Ukraine).
[13] Heyser R.C.: Acoustical Measurement by Time Delay Spectrometry. J. Audio Eng. Soc., vol. 15, 1967, October, p. 370.