title: Spatial impulse responses from a flexible baffled circular piston.
abstract: The theory of orthogonal polynomial (Zernike) expansions of functions on a disk, as used in the diffraction theory of optical aberrations, is applied to obtain (semi-) analytical expressions for the spatial impulse responses arising from a non-uniformly moving, baffled, circular piston. These expressions are in terms of the expansion coefficients of the non-uniformity and the responses of the orthogonal expansion functions. The latter impulse responses have a closed form as finite series involving the Legendre functions and the sinc function. The method is compared with a similar method, proposed by P. R. Stepanishen [J. Acoust. Soc. Am. 70, 1176-1181 (1981)] where zeroth order orthogonal Bessel functions, rather than Zernike polynomials, are used as expansion functions.
authors.affiliation: Philips Research Europe HTC 36, WO-02, NL-5656 AE Eindhoven, The Netherlands. ronald.m.aarts@philips.com
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Aarts
authors.forename: Augustus J E M
authors.initials: AJ
authors.lastname: Janssen