A concept for a digital loudspeaker array, composed of clusters of micro-radiating elements that form individual digital-to-acoustic converters, is studied. In this scheme a large-scale array is composed of subgroups of micro clusters. To accommodate the finite resolution of each cluster, noise shaping is proposed and parallels are drawn with the processes used in digital-to-analog converters. ...

not more than 200 words) An interesting possibility for improved surveillance capabilities in challenging underwater environments and against targets with low acoustic signatures is the use of multisensor systems combined with dataor information fusion. This work describes how data fusion can be used for tracking and classifying targets using passive underwater acoustic and electric field senso...

Traditionally, ocean acoustic signals have been acquired using hydrophones, which measure the pressure field and are typically omnidirectional. A vector sensor measures both the acoustic pressure and the three components of particle velocity. Assembled into an array, a vector sensor array (VSA) improves spatial filtering capabilities when compared with arrays of same length and same number of h...

In shallow water acoustic tomography, broadband mid-frequency acoustic waves (1 to 5 kHz) follow multiple ray-like paths to travel through the ocean. Travel-time (TT) variations associated to these raypaths are classically used to estimate sound speed perturbations of the water column using the ray theory. In this shallow water environment, source and receiver arrays, combined with adapted arra...

A biomimetic acoustic sensor was fabricated with single crystal PMN-PT piezoelectric cantilever array that can mimic functional properties of mammalian cochlea. Basilar membrane of mammalian cochlea can separate frequency components of input sound source and Ion channel phenomenon of hair cells on basilar membrane can generate action potentials for stimulating a nerve site. The piezoelectric ca...

An acoustic testing approach based on the concept of a microphone sensor surrounding the product under test is proposed. Partial microphone signals are processed simultaneously by a test system computer, according to the objective of the test. The spatial and frequency domain selectivity features of this method are examined. Sound-spatial visualization algorithm is observed. A test system desig...

Sounds received in the Gulf of Alaska at 3115 km from the ATOC/NPAL source at Kauai (75 Hz, 0.027-s resolution, bottom-mounted) are compared with acoustic and oceanographic models. Unlike data collected at stationary SOSUS arrays, these data come from a towed horizontal array at 372-m depth of military origin. A plausible identification of the acoustic reception is made despite the fact that on...

The MAPEX2000 experiments were conducted in the Mediterranean Sea in March, 2000 to determine seabed properties using a towed acoustic source and receiver array. Towed systems are advantageous because they are easy to deploy from a ship and the moving platform offers the possibility for estimating spatially variable (range-dependent) seabed properties. In this paper, seabed parameters are deter...