NOISE CANCELING HEADPHONE AND NOISE CANCELING EARMUFF

• US 20120063611A1
• Filed: 09/14/2011
• Published: 03/15/2012
• Est. Priority Date: 09/15/2010
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Audio-technica
• Original Assignee: Kabushiki Kaisha Audio-technica
• Inventors: Kimura, Tominori
• Granted Patent: US 8,774,421 B2
• Time in Patent Office: Days
• US Class Current: 381/71.6
• 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

Abstract

A noise canceling headphone includes a microphone provided in a headphone housing, collecting external sound, a canceling signal generating circuit generating a canceling signal in response to a signal output from the microphone which cancels external sound passing through the housing without being attenuated by a sound insulating characteristic of the headphone, a compensating signal generating circuit generating a compensating signal that compensates for the external sound attenuated by the sound insulating characteristic of the headphone, an adding circuit that adds a musical signal input from the exterior to the compensating signal, and a speaker unit that outputs an output signal from the adding circuit and the canceling signal.

Claims

1. A noise canceling headphone comprising:

a microphone provided in a headphone housing, collecting external sound;

a canceling signal generating circuit generating a canceling signal in response to a signal output from the microphone which cancels the external sound passing through the housing without being attenuated by a sound insulating characteristic of the headphone;

a compensating signal generating circuit generating a compensating signal that compensates for the external sound attenuated by the sound insulating characteristic of the headphone;

an adding circuit that adds a musical signal input from an exterior to the compensating signal; and

a speaker unit that outputs an output signal from the adding circuit and the canceling signal.

2. The noise canceling headphone according to claim 1, wherein

the compensating signal generating circuit is a filter circuit that generates a signal having a frequency characteristic opposite to the sound insulating characteristic in response to the signal output from the microphone.

3. The noise canceling headphone according to claim 1, wherein

the compensating signal generating circuit comprises

a difference operation circuit that outputs a difference between the signal output from the microphone and the canceling signal;

and

a band-pass filter circuit that extracts a signal only in a predetermined band from a signal output from the difference operation circuit.

4. The noise canceling headphone according to claim 3, wherein

the band-pass filter circuit extracts a signal only in a voice band.

5. The noise canceling headphone according to claim 1, further comprising:

a switch circuit that switches output of the compensating signal from the speaker unit.

6. The noise canceling headphone according to claim 5, further comprising:

a level detecting circuit that detects a signal level of the compensating signal, wherein

the switch circuit is operated to stop an output of the compensating signal when the signal level of the detected compensating signal is higher than a predetermined signal level.

7. The noise canceling headphone according to claim 5, further comprising:

a band level detecting circuit that detects a signal level of the compensating signal in a predetermined band, wherein

the switch circuit is operated to stop the output of the compensating signal when the signal level of the detected compensating signal in the predetermined band is higher than a predetermined level.

8. The noise canceling headphone according to claim 6, wherein

the predetermined level compared with the compensating signal is automatically varied.

9. The noise canceling headphone according to claim 7, wherein

the predetermined level compared with the compensating signal is automatically varied.

10. The noise canceling headphone according to claim 6, further comprising an operating section that allows a user to vary the predetermined level compared with the compensating signal.

11. The noise canceling headphone according to claim 7, further comprising an operating section that allows a user to vary the predetermined level compared with the compensating signal.

12. A noise canceling earmuff comprising:

a microphone provided in a headphone housing, collecting external sound;

a canceling signal generating circuit generating a canceling signal in response to a signal output from the microphone which cancels the external sound passing through the housing without being attenuated by a sound insulating characteristic of the headphone;

a compensating signal generating circuit generating a compensating signal that compensates for the external sound attenuated by the sound insulating characteristic of the headphone; and

a speaker unit that outputs the compensating signal and the canceling signal.