A plane wave generation method by wave number domain point focusing.
A method for generation of a wave-field that is a plane wave is described. This method uses an array of loudspeakers phased so that the field in the wave-number domain is nearly concentrated at a point, this point being at the wave-number vector of the desired plane wave. The method described here for such a wave-number concentration makes use of an expansion in spherical harmonics, and requires a relatively small number of measurement points for a good approximate achievement of a plane wave. The measurement points are on a spherical surface surrounding the array of loudspeakers. The input signals for the individual loudspeakers can be derived without a matrix inversion or without explicit assumptions about the loudspeakers. The mathematical development involves spherical harmonics and three-dimensional Fourier transforms. Some numerical examples are given, with various assumptions concerning the nature of the loudspeakers, that support the premise that the method described in the present paper may be useful in applications.
Center for Noise and Vibration Control, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Science Town, Daejeon 305-701, Korea. chang.jiho@gmail.com
Ji-Ho
JH
Chang
Jung-Woo
JW
Choi
Yang-Hann
YH
Kim
D000162:Acoustics / Q000295:instrumentation*; D000669:Amplifiers, Electronic; D004867:Equipment Design; D005583:Fourier Analysis; D006801:Humans; D008962:Models, Theoretical; D009040:Motion Pictures / Q000295:instrumentation; D009146:Music; D011571:Psychoacoustics; D018910:Video Games