Journal ArticleDOI
The use of broadband acoustic transducers and pulse-compression techniques for air-coupled ultrasonic imaging.
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TLDR
Capacitance transducers were used to generate wide bandwidth swept-frequency signals in air, which were then used to measure and image solid samples in through transmission, demonstrating that such signal processing techniques lead to an improvement in the signal to noise ratio and timing accuracy for air-coupled testing.About:
This article is published in Ultrasonics.The article was published on 2001-04-01. It has received 206 citations till now. The article focuses on the topics: Ultrasonic sensor & Ultrasonic testing.read more
Citations
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Journal ArticleDOI
Review of air-coupled ultrasonic materials characterization.
TL;DR: Developments in air-coupled transduction and electronics are briefly treated, although the emphasis here is on methods of characterization and inspection, and in overcoming limitations inherent in the use of such a tenuous sound coupling medium as air.
Journal ArticleDOI
Chirp excitation of ultrasonic guided waves
TL;DR: Broadband and narrowband chirp excitations are utilized to address the need to both test at multiple frequencies and achieve a high signal-to-noise ratio to minimize acquisition time.
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Air-coupled ultrasonic C-scan technique in impact response testing of carbon fibre and hybrid: glass, carbon and Kevlar/epoxy composites
TL;DR: In this article, an ultrasonic air-coupled C-scan technique and X-ray radiography were used to detect impact damage in thin carbon fiber/epoxy composite plates.
Journal ArticleDOI
Quality parameters of mango and potential of non-destructive techniques for their measurement — a review
TL;DR: This paper deals with some recent work reported on quality parameters, harvesting and post-harvest treatments in relation to quality of mango fruits and reviews on some of the potential non-destructive techniques that can be explored for quality determination of mango cultivars.
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Air-coupled ultrasonic NDE: experiments in the frequency range 750 kHz–2 MHz
TL;DR: In this paper, the authors examined the possibilities of air-coupled ultrasonic testing and imaging by means of a measurement system designed for both through-transmission and reflection technique.
References
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Journal ArticleDOI
Surface micromachined capacitive ultrasonic transducers
TL;DR: A theoretical model is proposed that agrees well with observed transducer behavior and is used to demonstrate that microfabricated ultrasonic transducers constitute an attractive alternative to piezoelectric transducers in many applications.
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A surface micromachined electrostatic ultrasonic air transducer
TL;DR: In this article, an electrical equivalent circuit model for electrostatic transducers based on the early work of Mason (1942) was designed and constructed for operation at 1.8 and 4.6 MHz.
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The design and characterization of micromachined air-coupled capacitance transducers
TL;DR: Air-coupled capacitance transducers have been manufactured using anisotropic etched silicon backplates and commercially available dielectric films (Kapton and Mylar) as discussed by the authors.
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Pulse Compression-Key to More Efficient Radar Transmission
TL;DR: The technique of pulse compression offers a means of increasing the average power available to illuminate radar targets without any loss at the receiver of the resolution needed for the tactical requirements of the system.
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Chirp signal matching and signal power optimization in pulse-echo mode ultrasonic nondestructive testing
M. Pollakowski,Helmut Ermert +1 more
TL;DR: In this paper, the authors proposed two methods to improve the overall efficiency of an ultrasonic pulse-echo system using nonlinear frequency modulation and square wave chirps derived from sine type chirp signals.