Topic
Acoustic interferometer
About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.
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TL;DR: In this article, the diffraction of an ion-acoustic wave from an obstacle is experimentally examined, and the measured diffraction pattern is compared with the measured radiation pattern from an equivalent source.
Abstract: The diffraction of an ion‐acoustic wave from an obstacle is experimentally examined. The measured diffraction pattern is compared with the measured radiation pattern from an equivalent source.
12 citations
Patent•
01 Sep 2009TL;DR: In this article, a hollow member is constructed in such a way that, when a reflective surface radiates reflected waves corresponding to incident sound waves falling from an external space on the opening portion and the reflective surface of the hollow member, a phase, in the opening part, of reflected waves produced by resonance of the resonator in response to the incident waves differs from a phase of reflected wave on the reflective surfaces.
Abstract: In a hollow member, a portion of a hollow region adjoining and communicating with an opening portion is constructed as an intermediate layer. The intermediate layer is constructed in such a manner that, when a reflective surface radiates reflected waves corresponding to incident sound waves falling from an external space on the opening portion and the reflective surface of the hollow member, a phase, in the opening portion, of reflected waves produced by resonance of the resonator in response to the incident waves differs from a phase of reflected waves on the reflective surface, and that the absolute value of a value obtained by dividing a specific acoustic impedance of the opening portion by a characteristic impedance of a medium of the opening portion is less than one. A sound absorbing effect through resonance-based action in the opening portion and a sound scattering effect through a flow of gas molecules.
12 citations
TL;DR: In this paper, the authors showed that the nonlinear properties of the medium can induce coupling among the modes in a multiresonant system and the theory is able to predict the threshold and the steady state response of subharmonic components.
Abstract: In our previous study [J. Acoust. Soc. Amer. 49, 119(A) (1971)], we showed that the nonlinear properties of the medium can induce coupling among the modes in a multiresonant system and the theory is able to predict the threshold and the steady‐state response of subharmonic components. Such a mechanism is further illustrated by observing the subharmonic generation phenomenon in an acoustic interferometer. The experimental investigation was conducted with a 1.5‐mHz driving signal and used filtered and degassed water as the medium. Data concerned with the actual modes of the interferometer, the loss factor associated with the subharmonic modes, and the threshold of subharmonic generation, with length of the interferometer and the driving frequency varying, are consistent with the analytic results provided that cavitation is carefully avoided. [The work was carried out at Harvard University and supported by the Office of Naval Research.]
12 citations
Patent•
18 Nov 1997
TL;DR: In this article, a liquid information measuring device was designed to measure the liquid level and the propagation time of a sound wave by use of a single sound wave oscillating element which produces the sound wave.
Abstract: PROBLEM TO BE SOLVED: To provide a liquid information measuring device designed to measure the liquid level and the propagation time of a sound wave by use of a single sound wave oscillating element which produces the sound wave. SOLUTION: An ultrasonic sensor S has an ultrasonic oscillating element 20 having a transmitting-receiving part 22 disposed in fuel and has reflectors 33, 34 disposed in the fuel. A reflector 35 reflects ultrasonic waves of mutually proximate frequencies transmitted from the ultrasonic oscillating element 20 and reflects the waves toward the ultrasonic oscillating element 20. The reflector 34 reflects toward the level of the fuel the ultrasonic waves transmitted from the ultrasonic oscillating element 20 and, when sound waves reflected from the level of the fuel impinge thereon, reflects the sound waves toward the transmitting-receiving part 22. A phase measuring apparatus 90 binarizes the received outputs derived from the reflected ultrasonic waves from the ultrasonic oscillating element 20, and calculates the phase difference between the binarized outputs. A microcomputer 40 calculates the propagation time of the sound wave and the level of the fuel according to the phase difference and each of the frequencies.
12 citations
Patent•
25 Jun 1998
TL;DR: In this article, the authors proposed a feasible acoustic impedance measuring device that can display acoustic impedance of an object to be measured in a high resolution and a high speed, and as an image.
Abstract: PROBLEM TO BE SOLVED: To provide a feasible acoustic impedance measuring device that can display acoustic impedance of an object to be measured in a high resolution and a high speed, and as an image. SOLUTION: Trapezoidal wave or rectangular wave of pulse signal is inputted from a pulsar circuit 2 to an ultrasonic transducer 1. Generated ultrasonic wave, after delayed by an acoustic delaying medium, is returned to the ultrasonic transducer 1 to generate a response signal. Parameters are extracted from frequency characteristic of this response signal, and the acoustic impedance is measured using a parameter strongly correlated with the acoustic impedance, and is displayed as an image.
12 citations