Active plus selective headset

• US 5,815,582 A
• Filed: 07/23/1997
• Issued: 09/29/1998
• Est. Priority Date: 12/02/1994
• Status: Expired due to Fees

• Current Assignee: Noise Cancellation Technologies, Inc. (NCT Group, Inc.)
• Original Assignee: Noise Cancellation Technologies, Inc. (NCT Group, Inc.)
• Inventors: Busch, Ralph, Claybaugh, David, Denenberg, Jeffrey N., Hohman, John
• Primary Examiner(s): Harvey, Minsun Oh
• Application Number:
  US08/899,090
• Time in Patent Office: 433 Days
• Field of Search: 381/72, 381/74, 381/103, 381/94.9, 381/155, 381/71.1, 381/71.6, 381/71.11, 381/71.12, 181/206, 379/406, 379/407, 379/410, 379/412, 379/387, 379/388, 379/390, 379/395
• US Class Current: 381/71.6
• CPC Class Codes: G10K 11/17837 by retaining part of the ambient acoustic environment, e.g. speech or alarm signals that the user needs to hear
• CPC Class Codes: G10K 11/17854 the filter being an adaptive filter
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17861 using additional means for damping sound, e.g. using sound absorbing panels
• CPC Class Codes: G10K 11/17881 the reference signal being an acoustic signal, e.g. recorded with a microphone
• 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 2210/108 Communication systems, e.g. where useful sound is kept and noise is cancelled
• CPC Class Codes: G10K 2210/1081 Earphones, e.g. for telephones, ear protectors or headsets
• CPC Class Codes: G10K 2210/3026 Feedback
• CPC Class Codes: G10K 2210/3027 Feedforward
• CPC Class Codes: G10K 2210/3028 Filtering, e.g. Kalman filters or special analogue or digital filters
• CPC Class Codes: G10K 2210/512 Wide band, e.g. non-recurring signals

Abstract

An active plus selective headset system for provision of active attenuation of broadband noise as well as speech filtering comprising a headset with reference microphones, residual microphones and speakers on each of a pair of open backed muffs and a controller means.

Claims

1. An active plus selective headset system which provides active broadband attenuation of noise as well as adaptive speech filtering, said system comprising:

a headset means adapted to be worn by a user;

reference sensing means on said headset means adapted to sense speech and noise signals;

speaker means on said headset means adapted to convey speech signals to a user'"'"'s ear; and

controller means adapted to control the speaker means based on input from the reference sensing means to provide active broadband attenuation of all random inband noise as well as adaptive speech filtering so that only the speech reaches the ear, wherein said active broadband attenuation is accomplished without synchronization pulses.

2. A system as in claim 1 wherein said headset means includes residual microphone means located on said headset means and including a feedback means connected to said speaker means.

3. A system as in claim 2 wherein said feedback means includes an adaptive speech filter means and a cancellation filter means.

4. A system as in claim 2 wherein said controller means is run by an adaptive feedforward algorithm.

5. A system as in claim 2 wherein said headset means includes an open backed muff.

6. A system as in claim 2 wherein said reference sensing means is an electret microphone.

7. A system as in claim 6 wherein said headset system comprises a pair of open backed muffs with the reference sensing means located on the outside of said muffs.

11. A system as in claim 1 wherein said reference sensing means is external of said speaker means on said headset means and said controller means is adapted to employ a feedforward method of noise cancellation.

12. A system as in claim 2 wherein said residual microphone means is internal of said speaker means on said headset means and said controller means is adapted to employ a feedback method of noise cancellation.

19. A system as in claim 1 wherein the reference sensing means is adapted to additionally sense warning signals, the speaker means is adapted to convey speech and warning signals to the user, and the controller means is adapted to provide active broadband attenuation of noise as well as speech filtering so that only the warning signals and speech reach the ear.

8. An active plus selective headset system which provides active broadband attenuation of noise as well as speech filtering, said system comprising:

a headset means adapted to be worn by a user, wherein said headset means includes residual microphone means located on said headset means and including a feedback means connected to said speaker means that includes an adaptive speech filter means adapted to filter speech from noise and a cancellation filter means;

reference sensing means on said headset means adapted to sense speech, noise and warning signals;

speaker means on said headset means adapted to convey speech and warning signals to a user'"'"'s ear; and

controller means adapted to control the speaker means based on input from the reference sensing means to provide active broadband attenuation of noise as well as speech filtering so that only the warning signals and speech reach the ear.

9. An active plus selective headset system which provides active broadband attenuation of noise as well as speech filtering, said system comprising:

a headset means adapted to be worn by a user, wherein said headset means includes residual microphone means located on said headset means and including a feedback means connected to said speaker means that includes an adaptive speech filter means and a cancellation filter means;

reference sensing means on said headset means adapted to sense speech, noise and warning signals;

speaker means on said headset means adapted to convey speech and warning signals to a user'"'"'s ear; and

controller means adapted to control the speaker means based on input from the reference sensing means to provide active broadband attenuation of noise as well as speech filtering so that only the warning signals and speech reach the ear;

wherein an output from said adaptive speech filtering means is mixed with an output from said controller means and a resulting signal passed to said speaker means.

10. An active plus selective headset system which provides active broadband attenuation of noise as well as speech filtering, said system comprising;

a headset means adapted to be worn by a user, wherein said headset means includes residual microphone means located on said headset means and including a feedback means connected to said speaker means that includes an adaptive speech filter means and a cancellation filter means;

reference sensing means on said headset means adapted to sense speech, noise and warning signals;

speaker means on said headset means adapted to convey speech and warning signals to a user'"'"'s ear; and

controller means adapted to control the speaker means based on input from the reference sensing means to provide active broadband attenuation of noise as well as speech filtering so that only the warning signals and speech reach the ear,

wherein an output from said adaptive speech filtering means is filtered by an impulse response of the cancellation means and subtracted from a signal from the residual microphone so as not to interfere with operation of said controller means.

13. A headset system for providing active broadband attenuation of unwanted random inband noise, as well as adaptive speech filtering, comprising:

a pair of muffs, each of said muffs comprising;

a reference microphone attached to an outside portion of said muff for sensing speech signals and unwanted random inband noise signals;

a speaker located on an inside portion of said muff; and

a controller attached to said reference microphone such that said signals sensed by said reference microphone act as an input to said controller;

said controller producing an anti-noise output at said speaker to eliminate said unwanted random inband noise signals at a user'"'"'s ear and removing noise from said speech signal by adaptive speech filtering so that the speech signals output to the user'"'"'s ear is clearer, wherein said elimination of said unwanted random inband noise signals is accomplished without synchronization pulses.

14. A headset system as in claim 13, further comprising a residual microphone attached to said speaker for sensing any unwanted random inband noise near the user'"'"'s ear and providing an output to said controller so that the anti-noise output can be adjusted to compensate for said unwanted random inband noise.

15. A headset system as in claim 13 wherein said controller includes a feedback compensator connected to said speaker.

17. A headset system as in claim 13 wherein said controller is operated based on an adaptive feedforward algorithm.

18. A headset system as in claim 13 wherein said reference sensing microphone is an electret microphone.

20. A headset system as in claim 13, wherein the reference microphone additional senses warning signals.

16. A headset system for providing active broadband attenuation of unwanted noise, as well as speech filtering, comprising:

a pair of muffs, each of said muffs comprising;

a reference microphone attached to an outside portion of said muff for sensing speech signals, warning signals, and unwanted noise signals;

a speaker located on an inside portion of said muff; and

a controller including a feedback compensator connected to said speaker and attached to said reference microphone such that said signals sensed by said reference microphone act as an input to said controller;

said controller producing an anti-noise output at said speaker to eliminate said unwanted noise signal at a user'"'"'s ear and removing noise from said speech signal so that the speech signals output to the user'"'"'s ear is clearer.

wherein said feedback compensator includes an adaptive speech filter and a cancellation filter.