1. An acoustic jammer assembly constructed for ejection from a signal tuben a submarine, said assembly comprising a cylindrical casing for containing various elements of the jammer; a high frequency acoustic noisemaker attached to one end of said casing and comprising a thick wall cylinder having the...http://www.google.fr/patents/US4194246?utm_source=gb-gplus-shareBrevet US4194246 - Noisemaker beacon
