Noise cancellation system

• US 6,041,126 A
• Filed: 07/24/1996
• Issued: 03/21/2000
• Est. Priority Date: 07/24/1995
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Terai, Kenichi, Hashimoto, Hiroyuki
• Primary Examiner(s): Lee, Ping
• Application Number:
  US08/685,573
• Time in Patent Office: 1,336 Days
• Field of Search: 381/71, 381/72, 381/73.1, 381/94, 381/71.6, 381/71.1, 381/71.8
• US Class Current: 381/71.6
• CPC Class Codes: H04M 1/19 Arrangements of transmitters, receivers, or complete sets to prevent eavesdropping, to attenuate local noise or to prevent undesired transmission; Mouthpieces or receivers specially adapted therefor circuit arrangements for preventing eavesdropping H04M1/68; telephone cabinets E04H1/14
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

A noise controlled type handset processes the output of non-directional noise detector installed outside of the handset by a first adaptive filter, delivers a control sound from a control speaker, controls the first adaptive filter so that the output of an error detector near the ear may be small, simultaneously processes the noise detection signal in a second adaptive filter, subtracts from the noise signal mixing into a bi-directional talking microphone, and controls the second adaptive filter so that the subtraction signal may be small, thereby taking back the signal of voice only by reducing noise by delivering through the speaker, and sending a transmission output at the same time.

Claims

1. A noise cancellation system having a mouth position and an ear position, and comprising:

noise detecting means for detecting noise,

a talking microphone installed near the mouth position,

a speaker installed near the ear position,

first filter means connected to the noise detecting means,

first adding/subtracting means for adding or subtracting by using an output of the talking microphone and an output of the first filter means, and sending the result to a talking signal output terminal,

error detecting means installed near the ear position for detecting an output of the speaker and the noise,

second filter means connected to the noise detecting means, and

second adding/subtracting means for adding or subtracting by using an output of the second filter means and a receiving signal, and sending the result to the speaker,

wherein the first filter means receives the detected noise, and a coefficient of the first filter means is updated by using the added or subtracted result outputted from the first adding/subtracting means,

the second filter means receives the detected noise, and a coefficient of the second filter means is updated by using an output of the error detecting means, and

the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

2. The noise cancellation system of claim 1, wherein the noise detecting means is provided at the back side of the speaker.

3. The noise cancellation system of claim 1,

wherein the noise detecting means has a non-directional characteristic and is provided near the talking microphone, and

the talking microphone has a maximum sensitivity substantially of a bidirectional characteristic in the direction of the talker'"'"'s mouth position.

4. The noise cancellation system of claim 3, further comprising:

voice detecting means for detecting a voice signal from the output signal of the talking microphone,

wherein the coefficient of the first filter means and/or the coefficient of the second filter means are not updated when the voice detecting means has detected the voice signal.

5. The noise cancellation system of claim 3, further comprising:

voice detecting means for detecting a voice signal from the receiving signal,

wherein the coefficient of the second filter means is not updated when the voice detecting means has detected the voice signal.

6. The noise cancellation system of claim 1, further comprising:

voice detecting means for detecting a voice signal from the output signal of the talking microphone,

wherein the coefficient of the first filter means and/or the coefficient of the second filter means are not updated when the voice detecting means has detected the voice signal.

7. The noise cancellation system of claim 1, comprising:

voice detecting means for detecting a voice signal from the receiving signal,

wherein the coefficient of the second filter means is not updated when the voice detecting means has detected the voice signal.

8. The noise cancellation system of claim 1, wherein said noise cancellation system is configured as a headphone, and

the noise detecting means, the speaker, the error detecting means, the first and second filter means, and the first and second adding/subtracting means are each provided as a set of two.

9. The noise cancellation system of claim 8, further comprising:

third filter means for the right side connected to the left noise detecting means of the two noise detecting means, and

third filter means for the left side connected to the right noise detecting means of the two noise detecting means,

wherein the third filter means for the right side makes use of an output of the right error detecting means of the two error detecting means, and updates the coefficient of the third filter means for the right side,

an output of the third filter means for the right side and an output of the second adding/subtracting means for the right side of the two second adding/subtracting means are added or subtracted, and inputted into the right speaker of the two speakers,

the third filter means for the left side makes use of an output of the left error detecting means of the two error detecting means, and updates the coefficient of the third filter means for the left side, and

an output of the third filter means for the left side and an output of the second adding/subtracting means for the left side of the two second adding/subtracting means are added or subtracted, and inputted into the left speaker of the two speakers.

10. A noise cancellation system having a mouth position and an ear position, and comprising:

noise detecting means for detecting noise,

a talking microphone installed near the mouth position,

a speaker installed near the ear position,

filter means connected to the noise detecting means,

adding/subtracting means for adding or subtracting by using an output of the talking microphone and an output of the filter means, and sending out the result to a talking signal output terminal, and

voice detecting means for detecting a voice signal from the output signal from the talking microphone,

wherein the filter means receives the detected noise, and a coefficient of the filter means is updated by using the added or subtracted result directly from the adding/subtracting means,

the coefficient of the filter means is not updated when the voice detecting means has detected the voice signal, and

the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

11. A noise cancellation system having a mouth position and an ear position, and comprising:

noise detecting means for detecting noise,

a talking microphone installed near the mouth position,

a speaker installed near the ear position,

filter means connected to the noise detecting means, and

adding/subtracting means for adding or subtracting by using an output of the talking microphone and an output of the filter means, and sending out the result to a talking signal output terminal,

wherein the noise detecting means has a non-directional characteristic and is provided near the talking microphone,

the talking microphone has a maximum sensitivity substantially of a bidirectional characteristic in the direction of the talker'"'"'s mouth position, and

the filter means receives the detected noise, and a coefficient of the filter means is updated by using the added or subtracted result directly from the adding/subtracting means, and

the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

12. The noise cancellation system of claim 11, further comprising:

voice detecting means for detecting a voice signal from the output signal of the talking microphone,

wherein the coefficient of the filter means is not updated when the voice detecting means has detected the voice signal.

13. The noise cancellation system of claim 11, wherein said noise cancellation system is configured as a headphone, and

the speaker and the error detecting means are each provided as a set of two.

14. A noise cancellation system having a mouth position and an ear position, and comprising:

a plurality of noise detectors for detecting noise,

a head gear of cap shape, helmet shape or antenna shape fixing all or part of the noise detectors of the plurality of noise detectors,

a first filter group having a plurality of first filters for receiving output signals from the noise detectors,

a second filter group having a plurality of second filters for receiving output signals from the noise detectors,

a talking microphone installed near the mouth position,

a speaker installed near the ear position, and

an error detector installed near the ear position; and

wherein each output signal of the first filters is subtracted from an output signal of the talking microphone, each coefficient of the first filters is updated by using this subtraction signal, the subtraction signal is sent to a talking signal output terminal, each coefficient of the second filters is updated by making use of an output signal of the error detector,

output signals of the second filter group, the subtraction signal, and a receiving signal from a receiving input terminal are added, and the sum signal is inputted into the speaker, and

the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

15. A noise cancellation system having a mouth position and an ear position, and comprising:

noise detecting means for detecting noise,

a talking microphone installed near the mouth position,

a speaker installed near the ear position,

first filter means connected to the noise detecting means,

first adding/subtracting means for adding or subtracting by using an output of the talking microphone and an output of the first filter means, and sending the result to a talking signal output terminal,

error detecting means installed near the ear position for detecting an output of the speaker and the noise,

second filter means connected to the noise detecting means,

second adding/subtracting means for adding or subtracting by using an output of the second filter means and a receiving signal, and sending the result to the speaker, and

voice detecting means for detecting a voice signal from the receiving signal; and

wherein the first filter means receives the detected noise, and a coefficient of the first filter means is updated by using the added or subtracted result outputted from the first adding/subtracting means,

the second filter means receives the detected noise, and a coefficient of the second filter means is updated by using an output of the error detecting means,

the coefficient of the second filter means is not updated when the voice detecting means has detected the voice signal, and

the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

16. A noise cancellation system having a mouth position and an ear position, and comprising:

noise detecting means for detecting noise,

a talking microphone installed near the mouth position,

a speaker installed near the ear position,

first filter means connected to the noise detecting means,

first adding/subtracting means for adding or subtracting by using an output of the talking microphone and an output of the first filter means, and sending the result to a talking signal output terminal,

error detecting means installed near the ear position for detecting an output of the speaker and the noise,

second filter means connected to the noise detecting means, and

second adding/subtracting means for adding or subtracting by using an output of the second filter means and a receiving signal, and sending the result to the speaker; and

wherein the first filter means receives the detected noise, and a coefficient of the first filter means is updated by using the added or subtracted result outputted from the first adding/subtracting means,

the second filter means receives the detected noise, and a coefficient of the second filter means is updated by using an output of the error detecting means,

the noise detecting means has a non-directional characteristic and is provided near the talking microphone,

the talking microphone has a maximum sensitivity substantially of a bidirectional characteristic in the direction of the talker'"'"'s mouth position, and

the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

17. The noise cancellation system of claim 16, further comprising:

voice detecting means for detecting a voice signal from the receiving signal,

wherein the coefficient of the second filter means is not updated when the voice detecting means has detected the voice signal.

18. The noise cancellation system of claim 17,

wherein said noise cancellation system is configured as a headphone, and

the speaker, the error detecting means, the second filter means, and the second adding/subtracting means are each provided as a set of two.

19. The noise cancellation system of claim 17, further comprising:

voice detecting means for detecting a voice signal from the output signal of the talking microphone,

wherein the coefficient of the first filter means and/or the coefficient of the second filter means are not updated when the voice detecting means has detected the voice signal.

20. A noise cancellation system having a mouth position and an ear position, and comprising:

noise detecting means for detecting noise,

a talking microphone installed near the mouth position,

a speaker installed near the ear position,

filter means connected to the noise detecting means, and

adding/subtracting means for adding or subtracting by using an output of the talking microphone and an output of the filter means, and sending out the result to a talking signal output terminal,

wherein the noise detecting means has a non-directional characteristic and is provided near the talking microphone such that an output signal of the noise detecting means correlates to a noise component of the output of the talking microphone so that a combined directivity of the noise detecting means and the talking microphone is cardiodirectional,

the talking microphone has a maximum sensitivity substantially of a bidirectional characteristic in the direction of the talker'"'"'s mouth position, and

the filter means receives the detected noise, and a coefecient of the filter means is updated by using the added or subtracted result from the adding/subtracting means.

21. The noise cancellation system of claim 20, further comprising:

voice detecting means for detecting a voice signal from the output signal of the talking microphone,

wherein the coefficient of the filter means is not updated when the voice detecting means has detected the voice signal.

22. The noise cancellation system of claim 20, wherein said noise cancellation system is configured as a headphone, and

the speaker and the error detecting means are each provided as a set of two.

23. The noise cancellation system of claim 20, wherein the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

24. A noise cancellation system having a mouth position and an ear position, and comprising:

noise detecting means for detecting noise,

a talking microphone installed near the mouth position,

a speaker installed near the ear position,

first filter means connected to the noise detecting means,

fist adding/subtracting means for adding or subtracting by using an output of the talking microphone and an output of the first filter means, and sending the result to a talking signal output terminal,

error detecting means installed near the ear position for detecting an output of the speaker and the noise,

second filter means connected to the noise detecting means, and

second adding/subtracting means for adding or subtracting by using an output of the second filter means and a receiving signal, and sending the result to the speaker,

wherein the first filter means receives the detected noise, sad a coefficient of the first filter means is updated by using the added or subtracted result outputted from the first adding/subtracting means,

the second filter means receives the detected noise, and a coefficient of the second filter means is updated by using an output of the error detecting means,

the noise detecting means has a non-directional characteristic and is provided near the talking microphone such that an output signal of the noise detecting means correlates to a noise component of the output of the talking microphone so that a combined directivity of the noise detecting means and the talking microphone is cardiodirectional, and

the talking microphone has a maximum sensitivity substantially of a bidirectional characteristic in the direction of the talker'"'"'s mouth position.

25. The noise cancellation system of claim 24, further comprising:

voice detecting means for detecting a voice signal from the output signal of the talking microphone,

wherein the coefficient of the first filter means and/or the coefficient of the second filter means are not updated when the voice detecting means has detected the voice signal.

26. The noise cancellation system of claim 25, wherein the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

27. The noise cancellation system of claim 24, further comprising:

voice detecting means for detecting a voice signal from the receiving signal,

wherein the coefficient of the second filter means is not updated when the voice detecting means has detected the voice signal.

28. The noise cancellation system of claim 27, wherein the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.

29. The noise cancellation system of claim 24, wherein the signal to be sent to the talking signal output terminal is also substantially sent to the speaker.