Timing synchronization of independent transmitting and receiving acoustic devices

When designing underwater surveillance acoustic arrays with multiple receiving hydrophones and transmitting transducers, researchers may have the luxury to develop custom data acquisitions systems with the appropriate number of receiving and transmitting channels located in one unit. This unit then digitizes and records the hydrophone signals using a single clock and processing circuitry. This ensures correct timing and a homogeneous signal path that reduces unknown variables affecting the signals. Fedenczuk is currently developing such a system as part of the CIMES (Center for Island, Maritime, and Extreme Environment Security) passive acoustics harbor and shallow water surveillance system. In the mean time we face a problem that researchers often encounter: working with multiple transmitting and receiving sources that operate independent of each other and on different timing clocks. In response to this problem we have designed a configuration technique that employs short-duration analog synchronization signals that match the timing of various transmission and acquisition systems with negligible signal loss and complete signal exclusion to and from the transducers and hydrophones. We successfully tested and employed this technique and present its results and schematics.