APPARATUS AND METHOD OF GENERATING DIRECTIONAL ACOUSTIC WAVE

• US 20040124739A1
• Filed: 04/03/2003
• Published: 07/01/2004
• Est. Priority Date: 12/31/2002
• Status: Abandoned Application

• Current Assignee: Vistapoint Inc.
• Original Assignee: Vistapoint Inc.
• Inventors: Li, Xiao Dong
• Application Number:
  US10/249,364
• Publication Number:
  US 20040124739A1
• Time in Patent Office: Days
• US Class Current: 310/311
• CPC Class Codes: G10K 11/34 using electrical steering of transducer arrays, e.g. beam steering constructional aspects B06B1/0607, B06B1/085
• CPC Class Codes: G10K 15/02 Synthesis of acoustic waves synthesis of speech G10L13/00
• CPC Class Codes: H04R 1/403 loud-speakers
• CPC Class Codes: H04R 2217/03 Parametric transducers where sound is generated or captured by the acoustic demodulation of amplitude modulated ultrasonic waves

Abstract

An apparatus and a method of generating a directional acoustic wave. The apparatus has a pre-compensator, an ultrasonic modulator, an amplitude modulator, an amplifier, and a directional ultrasonic beam emitter. The pre-compensator receives an audio signal to perform pre-compensation and then to generate a signal according to an ultrasonic air self-demodulation mechanism selected by a specific design. The ultrasonic modulator provides an ultrasonic carrier wave. The amplitude modulator receives the signal output by the pre-compensator and the ultrasonic carrier wave output by the ultrasonic modulator to load the signal into the ultrasonic carrier wave. The directional ultrasonic beam emitter is used to recover the audio signal by air self-demodulation. The directivity of the ultrasonic wave localizes the self-demodulation within the proceeding path of the wave beam, such that the audible sound carried by the carrier wave can only be heard locally to form the directional acoustic beam.

Claims

1. An apparatus for generating directional acoustic waves, comprising:

a pre-compensator, to receive an audio signal and perform pre-compensation thereon according to a selected ultrasonic air self-demodulation, and to output a signal;

an ultrasonic modulator, to provide an ultrasonic carrier wave;

an amplitude modulator, to receive the signal output by the pre-compensator and the ultrasonic carrier wave, and to load the signal into the ultrasonic carrier wave;

a power amplifier, to receive and amplify the ultrasonic carrier wave loaded with the signal; and

a directional ultrasonic beam emitter, to emit the ultrasonic carrier wave which has been self-demodulated by air and recover the audio signal to an audience.

2. The apparatus according to claim 1, wherein the directional ultrasonic beam emitter includes less than five sound generating units.

3. The apparatus according to claim 1, wherein the directional ultrasonic beam emitter has a directivity range of less than 30°

.

4. The apparatus according to claim 1, wherein the pre-compensator comprises a filter function.

5. The apparatus according to claim 1, wherein the pre-compensator is operative to pre-compensate the audio signal to allow the directional ultrasonic beam emitter to provide sufficient demodulation of the ultrasonic carrier wave within a predetermined short distance, and allow an audience to hear content of the audio signal.

6. The apparatus according to claim 5, wherein the predetermined short distance is shorter than 10 meters.

7. The apparatus according to claim 1, wherein the directional ultrasonic beam emitter includes an array device.

8. The apparatus according to claim 1, wherein the audio signal includes an audio electric signal.

9. A method of generating a directional acoustic wave, comprising:

receiving an audio signal;

pre-compensating the audio signal into a compensated audio signal according to a selected ultrasonic air self-demodulation;

loading the compensated audio signal into an ultrasonic carrier wave with a specific directivity; and

transmitting the ultrasonic carrier wave loaded with the compensated audio signal to an audience at a predetermined distance via air, wherein the ultrasonic carrier wave has been self-demodulated by air allowing the audience to hear the content of the audio signal.

10. The method according to claim 9, wherein the predetermined distance is smaller than 10 meters.

11. The method according to claim 9, wherein the audio signal is so pre-compensated allowing the ultrasonic wave to be self-demodulated within 1 meter.

12. The method according to claim 9, wherein the directivity includes a range smaller than 30°

.

13. The method according to claim 9, wherein the audio signal is pre-compensated according to the predetermined distance.

14. The method according to claim 9, wherein the step of receiving an audio signal includes receiving an audio electric signal.