Patent No. 6052336 Apparatus and method of broadcasting audible sound using ultrasonic sound as a carrier
Patent No. 6052336 Assignee: Austin Lowrey Associates , Springfield, VA (US) Apparatus and method of broadcasting audible sound using ultrasonic sound as a carrier (Lowrey, III, Apr 18, 2000) Abstract An ultrasonic sound source broadcasts an ultrasonic signal which is amplitude and/or frequency modulated with an information input signal originating from an information input source. If the signals are amplitude modulated, a square root function of the information input signal is produced prior to modulation. The modulated signal, which may be amplified, is then broadcast via a projector unit, whereupon an individual or group of individuals located in the broadcast region detect the audible sound. Notes: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to an apparatus and method of broadcasting an audible sound, and in particular, to an apparatus and method of broadc...