System for playback of pre-encoded signals through a parametric loudspeaker system

• US 7,343,017 B2
• Filed: 03/04/2002
• Issued: 03/11/2008
• Est. Priority Date: 08/26/1999
• Status: Expired due to Term

• Current Assignee: Turtle Beach Corporation
• Original Assignee: American Technology Incorporated (Emerson Electric Company)
• Inventors: Norris, Joseph O., Croft, James J. III
• Primary Examiner(s): Mei; Xu
• Application Number:
  US10/091,950
• Publication Number:
  US 20020111795A1
• Time in Patent Office: 2,199 Days
• Field of Search: None
• US Class Current: 381/77
• CPC Class Codes: H04B 11/00 Transmission systems employing sonic, ultrasonic or infrasonic waves
• CPC Class Codes: H04R 17/00 Piezoelectric transducers; Electrostrictive transducers piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners H10N30/00
• CPC Class Codes: H04R 2217/03 Parametric transducers where sound is generated or captured by the acoustic demodulation of amplitude modulated ultrasonic waves
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

A method and system for generating parametric output directly from a prerecorded and error corrected parametric signal for playback in a parametric loudspeaker system. The method includes the step of retrieving a pre-encoded audio signal from an electronically readable storage medium. In addition, an ultrasonic carrier signal has at least one sideband which represents the pre-encoded audio signal. The next step is playing back the pre-encoded audio signal through an ultrasonic amplifier and emitter.

Claims

1. A method for generating parametric output from a parametric loudspeaker system, comprising the steps of:

retrieving a pre-encoded audio signal from an electronically readable, optical storage medium with ultrasonic bandwidth, wherein an ultrasonic carrier signal having at least one sideband represents the pre-encoded audio signal; and

playing back the pre-encoded audio signal through an ultrasonic amplifier and emitter.

2. A method as in claim 1, wherein retrieving a pre-encoded audio signal further comprises the step of retrieving the pre-encoded audio signal which has been pre-processed.

3. A method as in claim 2, further comprising the step of retrieving the pre-encoded audio signal which has been pre-processed with distortion error correction.

4. A method as in claim 1, further comprising the step of modulating the ultrasonic carrier signal with the audio signal to produce the pre-encoded audio signal.

5. A method as in claim 1, further comprising the step of retrieving a processed audio signal from a magnetic storage medium with ultrasonic bandwidth.

6. A method as defined in claim 1, comprising of the further steps of:

positioning the parametric loudspeaker system with a projection orientation toward an intended listening area; and

playing back the pre-encoded audio signal in a region substantially limited to the intended listening area.

7. A method for storing parametric output for later playback from a parametric loudspeaker system, comprising the steps of:

modulating an ultrasonic carrier with an audio signal to create a modulated signal comprising the ultrasonic carrier signal and at least one sideband signal;

producing a processed signal that represents the modulated signal; and

storing the processed signal on an electronically readable storage medium;

wherein the step of modulating the ultrasonic carrier further comprises the step of applying distortion error correction to the audio signal to produce the processed signal.

8. A method as in claim 7, further comprising the step of playing back the processed signal from the electronically readable storage medium through an ultrasonic amplifier and emitter.

9. A device for storing parametric audio signals for output through a parametric loudspeaker system, comprising:

an electronically readable storage medium;

an ultrasonic carrier signal having at least one sideband which represents a pre-encoded audio signal, wherein said pre-encoded audio signal is stored on the electronically readable storage medium; and

an error correction module to pre-distort the modulated signal and form a processed signal.

10. The device as in claim 9, further comprising:

a retrieval unit for retrieving a pre-encoded audio signal from an electronically readable storage medium that has ultrasonic bandwidth; and

a playback module for playing back the pre-encoded audio signal.

11. The device as in claim 10, wherein the playback module further comprises:

an amplifier, coupled to the retrieval unit, for amplifying the pre-encoded ultrasonic signal; and

an ultrasonic emitter, coupled to the amplifier, configured to emit ultrasonic waves that de-couple in the air to audible sounds.

12. The device as in claim 9, further comprising a recording module for recording the pre-encoded audio signals onto the electronically readable storage medium, the recording means comprising:

a modulator, configured to pre-encode an ultrasonic carrier signal with the audio signal to form a processed signal; and

a write unit configured to write the processed signal to an electronically readable storage medium for replay by the parametric loudspeaker system.

13. The device as in claim 9, further comprising a compression module to compress the modulated signal and form a compressed signal.

14. A method for storing pre-encoded signals for a parametric loudspeaker system, comprising the steps of:

receiving at least one audio signal;

modulating an ultrasonic carrier signal with the audio signal to form a modulated signal comprising the ultrasonic carrier signal and at least one sideband signal;

applying error correction to the modulated signal to form a processed signal; and

storing the processed signal on an electronically readable storage medium for replay by the parametric loudspeaker system.

15. A method as in claim 14, further comprising the step of storing the processed signal on an optical storage medium with an ultrasonic bandwidth.

16. A method as in claim 14, further comprising the step of storing the processed signal on a magnetic storage medium with an ultrasonic bandwidth.

17. A method as in claim 14, further comprising the step of storing the processed signal on a high bandwidth storage medium with an ultrasonic bandwidth.

18. A method as in claim 14, wherein the step of applying error correction further comprises the step of applying error correction to correct for distortion introduced in the parametric demodulation process in air.

19. A method for generating parametric output through a parametric loudspeaker system, comprising the steps of:

receiving an incoming audio signal;

modulating an ultrasonic carrier signal with the audio signal to form a modulated signal comprising the ultrasonic carrier signal and at least one sideband signal;

applying error correction to the modulated signal to form a processed signal;

storing the processed signal on an electronically readable storage medium; and

playing back the processed signal through an ultrasonic amplifier and emitter.

20. A method as in claim 19, further comprising the step of storing the processed audio signal on an optical storage medium with an ultrasonic bandwidth.

21. A method as in claim 19, further comprising the step of storing the processed audio signal on a Super Audio Compact Disk (CD).

22. A method as in claim 19, further comprising the step of storing the processed audio signal on a magnetic storage medium with an ultrasonic bandwidth.

23. A method as in claim 22, further comprising the step of storing the processed audio signal on a hard drive used as the magnetic storage medium.

24. A method as in claim 19, further comprising the step of playing back the processed audio signal through an ultrasonic emitter having a film diaphragm.

25. A device to store pre-encoded signals for a parametric loudspeaker system, comprising:

an audio signal;

a modulator configured to modulate an ultrasonic carrier signal with the audio signal to produce a modulated signal comprising the ultrasonic carrier signal and at least one sideband signal;

an error correction unit configured to pre-correct the modulated signal for de-modulation distortion created by demodulation of parametric output in air; and

an electronically readable storage medium, having an ultrasonic bandwidth, configured to store the pre-corrected, modulated signal.

26. A method for pre-encoding signals for a parametric loudspeaker system through a computer network, comprising the steps of:

receiving an incoming audio signal at a network processing node;

processing an ultrasonic carrier signal with the audio signal using a computer to form a modulated signal comprising the ultrasonic carrier signal and at least one sideband; and

transmitting the modulated signal through the computer network for replay by the parametric loudspeaker system.

27. A method as in claim 26, further comprising the step of applying error correction to the modulated signal to form a processed signal.

28. A method as in claim 27, further comprising the step of transmitting the processed signal through the computer network for storage on an electronically readable storage medium.

29. A method for generating parametric output from a parametric loudspeaker system, comprising the steps of:

retrieving a pre-distorted audio signal from an electronically readable storage medium for storing an audible audio bandwidth;

modulating an ultrasonic carrier signal with the pre-distorted audio signal to form a pre-encoded audio signal comprising the ultrasonic carrier signal and at least one sideband signal; and

playing back the pre-distorted audio signal through an ultrasonic amplifier and emitter.

30. A method as in claim 29, wherein the step of modulating further comprises the step of modulating the retrieved signal using a switching modulator before playback.

31. A method as in claim 29, wherein the switching modulator further comprises a phase shifter and a quadrature modulator.

32. A method for generating parametric output through a parametric loudspeaker system, comprising the steps of:

receiving an incoming audio signal;

applying error correction to the audio signal to form an error corrected signal;

storing the error corrected signal on an electronically readable storage medium having an audible bandwidth;

retrieving the error corrected signal from the electronically readable storage medium;

modulating an ultrasonic carrier signal with the error corrected signal to form a modulated signal comprising the ultrasonic carrier signal and at least one sideband signal; and

playing back the modulated signal through an ultrasonic amplifier and emitter.

33. A method for generating parametric output from a parametric loudspeaker system, comprising the steps of:

retrieving a pre-processed audio signal from an electronically readable storage medium for storing an audible audio bandwidth, wherein the pre-processed audio signal has been distortion error corrected, modulated by an ultrasonic carrier, and compressed;

uncompressing the pre-processed audio signal; and

playing back the pre-encoded audio signal through an ultrasonic amplifier and emitter.

34. A method as in claim 33, further comprising the step of uncompressing the pre-processed audio signal that has been compressed to compensate for spectrum expansion associated with modulation by an ultrasonic carrier.

35. A method for generating parametric output through a parametric loudspeaker system, comprising the steps of:

receiving an incoming audio signal;

applying error correction, ultrasonic modulation, and compression to the audio signal to form an error corrected signal;

storing the error corrected signal on an electronically readable storage medium having an audible bandwidth;

retrieving the error corrected signal from the electronically readable storage medium; and

playing back the modulated signal through an ultrasonic amplifier and emitter.