Inverse system design based on the volterra modeling of a parametric loudspeaker system
Date of Issue2012
Nonlinear Acoustics: State-of-the-Art and Perspectives (2012)
School of Electrical and Electronic Engineering
Parametric loudspeaker systems have been widely used for projecting high directional audible sound beams. However, the nonlinear interaction among primary waves also generates harmonics, which distort the desired signal and degrade the sound quality. In order to investigate this inherent nonlinear mechanism, a baseband distortion model is developed from nonlinear system identification using an adaptive Volterra filter. For the conventional double-sideband amplitude modulation (DSBAM) technique, it is found that the harmonic distortion is largely attributed to the second harmonic. The adaptation results derived from both simulation and measurement indicate that the first few coefficients of the second-order kernel are dominant. Based on the Volterra model, a pth-order inverse system is designed to compensate the harmonic distortions present in the demodulated signal. Simulation and measurement results demonstrate that the harmonic distortion can be greatly reduced to an acceptable level when the inverse system is introduced with a suitable recursive order.
© 2012 American Institute of Physics. This paper was published in NONLINEAR ACOUSTICS State-of-the-Art and Perspectives and is made available as an electronic reprint (preprint) with permission of American Institute of Physics. The paper can be found at the following official DOI: [http://dx.doi.org/10.1063/1.4749374]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.