NOISE CANCELLATION FOR WIRELESS AUDIO DISTRIBUTION SYSTEM

• US 20070242834A1
• Filed: 05/10/2007
• Published: 10/18/2007
• Est. Priority Date: 10/30/2001
• Status: Active Grant

• Current Assignee: Aptiv Technologies Limited (BorgWarner Incorporated)
• Original Assignee: Unwired Technology, LLC (Aptiv PLC)
• Inventors: Richenstein, Lawrence, Coutinho, Roy
• Granted Patent: US 8,208,654 B2
• Time in Patent Office: Days
• US Class Current: 381/71.800
• CPC Class Codes: G10K 11/17827 Desired external signals, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 11/17855 for improving speed or power requirements
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 11/17885 additionally using a desired external signal, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 2210/1081 Earphones, e.g. for telephones, ear protectors or headsets
• CPC Class Codes: H04H 20/61 for local area broadcast, e.g. instore broadcast
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S

Abstract

A wireless audio distribution system may have a wireless transmitter, responsive to a plurality of audio input channels, for transmitting signals carrying the audio, a receiver, responsive to the transmitted signals for selecting one or more of the audio input channels to be reproduced in accordance with local setting selectors at the receiver. Speaker audio channel anti-noise signals can be subtracted from the head audio channel to cancel the noise related to the playing of the speaker audio on the speakers while the headset audio is played on the headset. Analog anti-noise signals can be produced by use of a microphone associated with the headset and later subtracted from the headset audio.

Claims

1. A noise canceling wireless audio distribution system, comprising:

a plurality of monaural and/or stereo audio channels;

a selection switch for selecting a speaker audio channel, from the plurality of audio channels, to be played on a plurality of speakers in a vehicle;

a wireless transmitter for transmitting a serial bitstream including at least a subset of the plurality of audio channels combined with digital control codes;

a wireless receiver responsive to the serial bitstream for selecting, and playing on a headset associated with the wireless receiver, a headset audio channel from the plurality of audio channel; and

a noise cancellation processor in the headset, for canceling noise related to the playing of the speaker audio channel on the speakers while the headset audio channel is played on the headset in accordance with the control codes in the serial bitstream, by subtracting speaker anti-noise signals related to the wirelessly received speaker audio channel from the headset audio channel being played.

2. The invention of claim 1 wherein operation of the selector switch to select the speaker audio channel causes the speaker audio channel to be identified by the wireless receiver in the serial bitstream.

3. The invention of claim 2 wherein operation of the selector switch to select the speaker audio channel causes the speaker audio channel to be included in the serial bitstream in a known position related to the other audio channels.

4. The invention of claim 1 wherein the noise cancellation processor further comprises:

a correction table for modifying the wirelessly received speaker audio channels, in accordance with a path between the headset and at least one of the plurality of speakers, to develop the anti-noise signals.

5. The invention of claim 1 further comprising:

at least one microphone associated with the headset for detecting ambient audio.

6. The invention of claim 5 wherein characteristics of the path are applied to the correction table in response to the detected ambient audio.

7. The invention of claim 5 wherein the noise cancellation processor further comprises:

a correction table generator for controlling the correction table in accordance with the wirelessly received speaker audio.

8. The invention of claim 5 wherein correction table generator is responsive to ambient audio to produce an analog anti-noise signals to be subtracted from the headset audio channel.

9. The invention of claim 8 further comprising:

a digital to analog converter for converting the headset audio channel, after the speaker anti-noise signals have been subtracted therefrom, to analog signals so that the analog anti-noise signals can be subtracted therefrom to produce analog headset audio to be played by the headset.