Title :
Chirp excitation of ultrasonic probe for high-rangeability gas flowmetering
Author :
Folkestad, T. ; Mylvaganam, K.S. ; Bersaas, S.L. ; Ullebust, B.
Author_Institution :
Dept. of Sci. & Technol., Michelsen Inst., Bergen, Norway
Abstract :
The adaptive signal processing based on pulse compression in conjunction with the ray rescue-angle orientation of the transducers is another important feature for achieving high-rangeability ultrasonic gas flowmetering. A technique for achieving the necessary broad bandwidth of the ultrasonic transducer, which has to be excited within a low-frequency band due to the increased absorption of ultrasound in gas with frequency, is described. A signal-processing system suitable for very low and high times-of-flight and their differences is also presented. Discussed is the use of a special filtering technique based on assessing the gradient of the time series (in ascending order) of times-of-flight which eliminates spurious times-of-flight observed in actual interrogations of the flow
Keywords :
acoustic imaging; flow visualisation; flowmeters; ultrasonic transducers; adaptive signal processing; broad bandwidth; chirp excitation; high-rangeability gas flowmetering; low-frequency band excitation; pulse compression; ray rescue-angle orientation; signal-processing system; time series gradient; times-of-flight; ultrasonic transducer; Absorption; Adaptive signal processing; Bandwidth; Chirp; Filtering; Frequency; Probes; Pulse compression methods; Ultrasonic imaging; Ultrasonic transducers;
Conference_Titel :
Ultrasonics Symposium, 1989. Proceedings., IEEE 1989
Conference_Location :
Montreal, Que.
DOI :
10.1109/ULTSYM.1989.67157