Sara Andersson; Michael Einwächter ISRN: BTH-AMT-EX--2011/CI-04--SE, pp. 54. ING/School of Engineering, 2011.
In this work an acoustic parametric array for underwater use was designed, built and tested. An acoustic parametric array creates a focused beam of sound with the help of the nonlinearity of the water. This was in this work accomplished with a multi-element speaker especially designed for underwater acoustics and an ultrasound signal generation system.
This parametric array has multiple purposes, both in ommercial and military use. One could use such an array to scan the bottom of the ocean, or aim it horizontally in front of a boat to scan for objects hidden in unknown water. The array can also be used for sending confidential information
between two vessels, or for surveillance of for example harbor entrances.