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:
Jun. 02, 2020
Filed:
Oct. 17, 2018
The Board of Trustees of the University of Illinois, Urbana, IL (US);
Nirupam Roy, Champaign, IL (US);
Romit Roy Choudhury, Champaign, IL (US);
Haitham Al Hassanieh, Champaign, IL (US);
Board of Trustees of the University of Illinois, Urbana, IL (US);
Abstract
An audio transmitter includes a first ultrasonic speaker associated with a first channel; a second ultrasonic speaker co-located with the first ultrasonic speaker and associated with a second channel; and a waveform generator to: frequency modulate a first inaudible signal at a first ultrasonic frequency, to generate a modulated inaudible signal; drive, over the first channel, the first ultrasonic speaker with the modulated inaudible signal; and drive, over the second channel, the second ultrasonic speaker with a second inaudible signal at a second ultrasonic frequency so that a combination of the modulated inaudible signal and the second inaudible signal arrive at a microphone system. The second ultrasonic frequency is selected to frequency shift the modulated inaudible signal, upon demodulation by hardware of the microphone system, causing non-linearities of the hardware to translate the first ultrasonic frequency to below a low-pass filter cutoff frequency that is recordable by the microphone system.