Acoustic waveguide giving definite surface radiation or reception

摘要

The acoustic waveguide is made up of walls which are partially transparent to sound and walls which are non-transparent to sound. The diameter of the waveguide is determined specifically to generate a fixed sound wave pattern. The inner contour of the waveguide is preferably round. Guides may be provided to feed the sound waves from a sound convertor into the waveguide. Preferably, holes are provided in the waveguide through which the specific waves are fed. The waveguide may be the wave conducting part of an ultra-sonic sensor with at least one ultra-sound convertor. The latter is connected on or in at least one acoustic waveguide.