Patent ID: 7062050
Filing Date: 2006-06-13
Classification: H04R

Abstract:
1. A nonlinear acoustic system, comprising: at least one audio signal source configured to provide at least one audio signal; signal processing circuitry configured to receive the audio signal and process the audio signal using a modeled representation of a nonlinear inversion of an ultrasonic signal demodulation function, the modeled representation having an absolute error of less than approximately 10% for ultrasonic output levels ranging from approximately 20 Pa to at least approximately 1000 Pa; a modulator configured to receive the processed signal and to convert the processed signal into ultrasonic frequencies; and at least one acoustic transducer configured to receive the converted signal and project the converted signal through a propagation medium along a selected path, thereby regenerating the audio signal along at least a portion of the selected path, wherein the ultrasonic signal demodulation function is expressed as x∝ytanh(γy), “x” denoting the regenerated audio signal, “y” denoting the processed audio signal, and “γ” denoting a coefficient primarily depending on the converted signal output level.