VIBRATION MEASUREMENTS ON AN ULTRASONIC TRANSDUCER BY A LASER DOPPLER VIBROMETER: Comparison between velocity and displacement measurements

摘要

In this paper two possible measurement chains, both based on laser vibrometers, to analyze performances of ultrasonic transducers are discussed. The two possible approaches are based on the measurement of transducer vibration velocity or displacement. For velocity data acquisition and processing a Polytec OFV 1102 -OFV 300 laser vibrometer and a Le Croy LC334 oscilloscope have been used. For displacement measurements a measurement chain based on a Polytec OFV 303 optical head and a fringe counter was set-up. Transducer has been excited by sine sweep using a signal generator. Transfer functions between electrical driving signal (tension and current) and vibration velocity of transducer surface have been measured on different transducers, working at different temperatures and in different points. Displacement measurements are actually in progress.