Bandwidth enhancement : correcting magnitude and phase distortion in wideband piezoelectric transducer systems
Assous, Said; Rees, John; Lovell, Mike; Linnett, Laurie; Gunn, David. 2011 Bandwidth enhancement : correcting magnitude and phase distortion in wideband piezoelectric transducer systems. In: Ebrahimi, Farzad, (ed.) Advances in piezoelectric transducers. InTech, 75-84.Before downloading, please read NORA policies.
Acoustic ultrasonic measurements are widespread and commonly use transducers exhibiting resonant behaviour due to the piezoelectric nature of their active elements, being designed to give maximum sensitivity in the bandwidth of interest. We present a characterisation of such transducers that provides both magnitude and phase information describing the way in which the receiver responds to a surface displacement over its frequency range. Consequently, these devices work efficiently and linearly over only a very narrow band of their overall frequency range. In turn, this causes phase and magnitude distortion of linear signals. To correct for this distortion, we introduce a software technique, which considers only the input and the final output signals of the whole systemwhich is therefore generally applicable to any acoustic system. By correcting for the distortion of the magnitude and phase responses, we have ensured the signal seen at the receiver replicates the desired signal. We demonstrate a bandwidth extension on the received signal from 60-130 kHz at -6dB to 40-200 kHz at -1dB in a test system. The linear chirp signal we used to demonstrate this method showed the received signal to be almost identical to the desired linear chirp. Such systemcharacterisation will improve ultrasonic techniques when investigating material properties by maximising the accuracy of magnitude and phase estimations.
|Item Type:||Book Section|
|Programmes:||BGS Programmes 2010 > Land Use, Planning and Development|
|Additional Information:||This paper is available for free download from http://www.intechopen.com/books/advances-in-piezoelectric-transducers/bandwidth-enhancement-correcting-magnitude-and-phase-distortion-in-wideband-piezoelectric-transducer#|
|Date made live:||13 Mar 2012 11:25|
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