Hydrophone array polarity test circuit

Abstract Soft Defect Localization (SDL) is a dynamic laser-based failure analysis technique that can detect circuit upsets (or cause a malfunctioning circuit to recover) by generation of localized heat or photons from a rastered laser beam. SDL is the third and seldom used method on the LSM tool. Most failure analysis LSM sessions use the endo-thermic mode (TIVA, XIVA, OBIRCH), followed by the photo-injection mode (LIVA) to isolate most of their failures. SDL is seldom used or attempted, unless there is a unique and obvious failure mode that can benefit from the application. Many failure analysts, with a creative approach to the analysis, can employ SDL. They will benefit by rapidly finding the location of the failure mechanism and forgoing weeks of nodal probing and isolation. This paper will cover circuit signal conditioning to allow for fast dynamic failure isolation using an LSM for laser stimulation. Discussions of several cases will demonstrate how the laser can be employed for triggering across a pass/fail boundary as defined by voltage levels, supply currents, signal frequency, or digital flags. A technique for manual input of the LSM trigger is also discussed.

Download Full-text

Portable Multi-Hydrophone Array for Field and Laboratory Measurements of Odontocete Acoustic Signals DURIP

10.21236/ada599979 ◽

2013 ◽

Author(s):

Paul E. Nachtigall ◽

Aude H. Pacini

Keyword(s):

Acoustic Signals ◽

Laboratory Measurements ◽

Hydrophone Array

Download Full-text

Estimation of the Noise Source Level of a Commercial Ship Using On-Board Pressure Sensors

Applied Sciences ◽

10.3390/app11031243 ◽

2021 ◽

Vol 11 (3) ◽

pp. 1243

Author(s):

Hongseok Jeong ◽

Jeung-Hoon Lee ◽

Yong-Hyun Kim ◽

Hanshin Seol

Keyword(s):

Noise Source ◽

Pressure Sensors ◽

Low Frequency ◽

Frequency Resolution ◽

Source Strength ◽

Recording Time ◽

Source Level ◽

The One ◽

Hydrophone Array ◽

Good Agreement

The dominant underwater noise source of a ship is known to be propeller cavitation. Recently, attempts have been made to quantify the source strength using on-board pressure sensors near the propeller, as this has advantages over conventional noise measurement. In this study, a beamforming method was used to estimate the source strength of a cavitating propeller. The method was validated against a model-scale measurement in a cavitation tunnel, which showed good agreement between the measured and estimated source levels. The method was also applied to a full-scale measurement, in which the source level was measured using an external hydrophone array. The estimated source level using the hull pressure sensors showed good agreement with the measured one above 400 Hz, which shows potential for noise monitoring using on-board sensors. A parametric study was carried out to check the practicality of the method. From the results, it was shown that a sufficient recording time is required to obtain a consistent level at high frequencies. Changing the frequency resolution had little effect on the result, as long as enough data were provided for the one-third octave band conversion. The number of sensors affected the mid- to low-frequency data.

Download Full-text

Sound source location by difference of phase, on a hydrophone array with small dimensions

The Journal of the Acoustical Society of America ◽

10.1121/1.1333421 ◽

2001 ◽

Vol 109 (1) ◽

pp. 430-433 ◽

Cited By ~ 4

Author(s):

Karsten Brensing ◽

Katrin Linke ◽

Dietmar Todt

Keyword(s):

Sound Source ◽

Source Location ◽

Hydrophone Array

Download Full-text

Test Method of Current Leakage for Dielectric Paste

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.220-223.1573 ◽

2012 ◽

Vol 220-223 ◽

pp. 1573-1576

Author(s):

Zhi Hong Hou

Keyword(s):

Glass Substrate ◽

Dielectric Layer ◽

Screen Printing ◽

Test Method ◽

Conducting Layer ◽

Current Leakage ◽

Test Circuit ◽

Conductive Line ◽

Hybrid Microcircuit ◽

Sintering Processes

A test method of current leakage for dielectric paste was proposed by simulating the application processes of dielectric paste for manufacturing the dielectric layer in the multilayer thick film hybrid microcircuit. That is, by screen printing and sintering processes, the sliver conducting layer was fabricated on the surface of glass substrate, and then dielectric layer, finally the glass substrate sample with conducting layer and dielectric layer was dipped in 5 Wt% NaCl aqueous solution. The conductive line was soldered on the silver conducting layer to form the test circuit, and powered with 5 volts direct power, the current in the test circuit was taken as the current leakage of the dielectric paste. The method may be used to evaluate the current leakage of dielectric paste.

Download Full-text