The determination of amplitude and phase of the hydrophone sensitivity using two techniques based on time-delay spectrometry is presented. The frequency range in which the technique can be applied is from 1 MHz to 50 MHz. The agreement with the results obtained by alternative calibration techniques is excellent, which emphasises the correct working of this coherent technique. Introduction Calib...

A new method is presented for hydrophone calibration using the Khokhlov Zabolotskaya Kuznetsov (KZK) equation. Simulated and experimental on-axis finite amplitude distortion time waveforms and frequency spectra are compared. The hydrophone calibration up to 100 MHz is estimated for two different hydrophones.

Aimed at lithotripter acoustic output measurements, a new fibre-optic probe hydrophone overcomes most of the problems involved with the use of piezoelectric hydrophone technology in non-linear ultrasonic and shock-wave fields. The fibre-optic principle allows for extremely wide bandwidth (larger than 1 GHz) and superior electromagnetic shielding. Contrary to hitherto existing hydrophones a high...

The MEMS vector hydrophone is a novel acoustic sensor with a "four-beam-cilia" structure. Based on the MEMS vector hydrophone with this structure, the paper studies the method of estimated direction of arrival (DOA). According to various research papers, many algorithms can be applied to vector hydrophones. The beam-forming approach and bar graph approach are described in detail. Laboratory tes...

Two hydrophone calibration techniques are presented which provide amplitude and phase of hydrophone sensitivity. Heterodyne time-delay spectrometry can be applied in the frequency range from 0.5 to 50 MHz to all common hydrophones but needs a standard to obtain absolute values. A pulse technique between 1 and 70 MHz allows exploiting of an optical multilayer hydrophone as a phase standard. In c...

Aperture extension is achieved in this novel ESPRITbased two-dimensional angle estimation scheme using a uniform rectangular array of vector hydrophones spaced much farther apart than a half-wavelength. A vector hydrophone comprises two or three spatially co-located, orthogonally oriented identical velocity hydrophones (each of which measures one Cartesian component of the underwater acoustical...

The aim of the paper is to show the drift of the electrical noise level of the hydrophone NAXYS, model Ethernet 02345 during a long time period, about 1 year, and find some relations between the hydropne’s drift and the changed of the environment parameters. Keywords— background level, hydrophone, correlation I. INTRODUCCIÓN This article is centred in the electrical noise of the hydrophone loca...