The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 07, 2015
Filed:
Jul. 18, 2011
William John Lamb, Eindhoven, NL;
Ronaldus Maria Aarts, Eindhoven, NL;
William John Lamb, Eindhoven, NL;
Ronaldus Maria Aarts, Eindhoven, NL;
Other;
Abstract
A parametric loudspeaker system comprises a pre-compensator () for generating a pre-compensated envelope signal by applying a pre-compensation to the input audio signal where the pre-compensation compensates for distortion of in-air demodulation of the modulated ultrasound signal. A pre-modulator () generates a complex base band signal generating a phase signal from the pre-compensated envelope signal using a predetermined function for determining a phase signal from an amplitude signal such that the corresponding complex signal has either suppressed negative or positive frequencies. The complex base band signal is then generated to have an amplitude corresponding to the pre-compensated envelope signal and a phase corresponding to the phase signal. A modulator () quadrature modulates the complex base band signal on an ultrasonic quadrature carrier and an output circuit () drives the ultrasound transducer () from the modulated signal. The invention may allow effective yet low resource pre-compensation for a suppressed or single sideband modulated modulated ultrasound signal.