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Class Information
Number: 381/71.13
Name: Electrical audio signal processing systems and devices > Acoustical noise or sound cancellation > Counterwave generation control path > Analog or nonadaptive
Description: Subject matter in which the out-of-phase replica is generated using either analog circuitry or an electrical circuit having a fixed transfer function.
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7103188 |
Variable gain active noise cancelling system with improved residual noise sensing |
Sep. 5, 2006 |
| 7031460 |
Telephonic handset employing feed-forward noise cancellation |
Apr. 18, 2006 |
| 6990207 |
Active noise control system |
Jan. 24, 2006 |
| 6944303 |
Noise cancellation device, engine-noise cancellation device, and noise cancellation method |
Sep. 13, 2005 |
| 6688422 |
Method and apparatus for actively influencing the intake noise of an internal combustion engine |
Feb. 10, 2004 |
| 6625287 |
Enhancing automatic noise reduction using negative output resistance |
Sep. 23, 2003 |
| 6449369 |
Method and device for hybrid active attenuation of vibration, particularly of mechanical, acoustic or similar vibration |
Sep. 10, 2002 |
| 6320968 |
Adaptive noise rejection system and method |
Nov. 20, 2001 |
| 6278786 |
Active noise cancellation aircraft headset system |
Aug. 21, 2001 |
| 6259792 |
Waveform playback device for active noise cancellation |
Jul. 10, 2001 |
| 6151397 |
Method and system for reducing undesired signals in a communication environment |
Nov. 21, 2000 |
| 6061456 |
Noise cancellation apparatus |
May. 9, 2000 |
| 5848169 |
Feedback acoustic energy dissipating device with compensator |
Dec. 8, 1998 |
| 5825897 |
Noise cancellation apparatus |
Oct. 20, 1998 |
| 5781640 |
Adaptive noise transformation system |
Jul. 14, 1998 |
| 5732143 |
Noise cancellation apparatus |
Mar. 24, 1998 |
| 5638454 |
Noise reduction system |
Jun. 10, 1997 |
| 5627746 |
Low cost controller |
May. 6, 1997 |
| 5619581 |
Active noise and vibration cancellation system |
Apr. 8, 1997 |
| 5604813 |
Industrial headset |
Feb. 18, 1997 |
| 5590206 |
Noise canceler |
Dec. 31, 1996 |
| 5488666 |
System for suppressing sound from a flame |
Jan. 30, 1996 |
| 5440642 |
Analog noise cancellation system using digital optimizing of variable parameters |
Aug. 8, 1995 |
| 5412735 |
Adaptive noise reduction circuit for a sound reproduction system |
May. 2, 1995 |
| 5371801 |
Energy absorption apparatus |
Dec. 6, 1994 |
| 5363451 |
Method and apparatus for the active reduction of compression waves |
Nov. 8, 1994 |
| 5315661 |
Active high transmission loss panel |
May. 24, 1994 |
| 5305387 |
Earphoning |
Apr. 19, 1994 |
| 5276740 |
Earphone device |
Jan. 4, 1994 |
| 5267321 |
Active sound absorber |
Nov. 30, 1993 |
| 5221185 |
Method and apparatus for synchronizing rotating machinery to reduce noise |
Jun. 22, 1993 |
| 5182774 |
Noise cancellation headset |
Jan. 26, 1993 |
| 5138664 |
Noise reducing device |
Aug. 11, 1992 |
| 5046874 |
Impact printer print head with active sound pressure attenuation means |
Sep. 10, 1991 |
| 5047736 |
Selective interference reduction in transmission lines |
Sep. 10, 1991 |
| 4985925 |
Active noise reduction system |
Jan. 15, 1991 |
| 4953217 |
Noise reduction system |
Aug. 28, 1990 |
| 4947434 |
Electronic attenuator |
Aug. 7, 1990 |
| 4899387 |
Active low frequency acoustic resonance suppressor |
Feb. 6, 1990 |
| 4805733 |
Active silencer |
Feb. 21, 1989 |
| H417 |
Headset for ambient noise suppression |
Jan. 5, 1988 |
| 4625083 |
Voice operated switch |
Nov. 25, 1986 |
| 4589133 |
Attenuation of sound waves |
May. 13, 1986 |
| 4527282 |
Method and apparatus for low frequency active attenuation |
Jul. 2, 1985 |
| 4490841 |
Method and apparatus for cancelling vibrations |
Dec. 25, 1984 |
| 4489441 |
Method and apparatus for cancelling vibration |
Dec. 18, 1984 |
| 4455675 |
Headphoning |
Jun. 19, 1984 |
| 4449235 |
Electronic cancelling of acoustic traveling waves |
May. 15, 1984 |
| 4122303 |
Improvements in and relating to active sound attenuation |
Oct. 24, 1978 |
| 4025724 |
Noise cancellation apparatus |
May. 24, 1977 |
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