32-Channel Digitizer for a Moored Hydrophone Array for Low-to-Mid Frequency Shallow-Water Acoustics Experiments.

摘要

The long-term goal is the acquisition of an in situ, 32-channel digitizer capable of sampling at a rate of 8kHz, with a maximum depth rating of 1 km and data storage capacity sufficient to support continuous recording for a 10-day deployment. This system, when coupled to an existing, 32-channel hydrophone array owned by the Naval Postgraduate School, will enable future research efforts to investigate three-dimensional effects on sound propagation caused by a sharp front, large amplitude internal waves, and significant bathymetric changes, which are common environmental features in a shelf-slope environment. The procurement of the proposed 32-channel digitizer will help to fill the data and knowledge gaps that exist in the shallow-water acoustics research community. The first deployment will be in the next multi- institutional shallow-water acoustics experiment that is targeted for the FY14 timeframe. This project will obtain an underwater digitizer system for an existing 32-element, 155m aperture hydrophone array. The combined digitizer and array system will enable the measurement of the horizontal or vertical properties (depending on the moored orientation) of the low-to-mid frequency (500 3,000 Hz) shallow-water sound field. This electronics system will be capable of: 8kHz continuous sampling over a 10-day period; an Analog-to-Digital converter resolution of 16-bits; a correctable clock stability of 1 ms over the deployment; and a 1km maximum operating depth.