PARRAY technical papers presented at scientific and technical meetings

The parametric acoustic receiving array (PARRAY) exploits the inherent nonlinearity in the pressure-density relationship of water to achieve directional reception of low frequency acoustic waves using only two small high frequency transducers and some associated electronics. This report describes the PARRAY and summarizes several papers on the subject that have been presented at scientific and technical meetings. Copies of the papers are included as appendices. Procedures for selection of optimal parameter values are developed. State of the art advances in stable oscillators, reception of sideband signals with very small modulation indices, and simple high efficiency transducer elements are described. Results of experiments with a 340 m aperture PARRAY are presented which demonstrate that the experimental PARRAY is ambient noise limited in Lake Travis (Texas).