US5293578A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise reducing device
Assignee: Denso Ten Ltd
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Filing: 1992-06-03
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Granted: 1994-03-08
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Expires: 2012-06-03
Abstract
Abstract A noise reducing device including a noise silencing device having a delay unit for delaying a phase of the noise wave, an amplifying unit for adjusting a gain of the delayed noise wave, a superposing unit for superposing the delayed noise wave as the noise silencing wave, a frequency selecting unit for selecting at least one frequency with respect to the noise wave, a factor selecting unit for selecting at least one of a delaying factor used for the delaying unit and a gain factor used for the amplifying unit with respect to the selected frequency, and a controlling unit for controlling at least one of the delaying unit and amplifying unit utilizing the selected delaying factor and a gain factor, respectively, whereby a noise silencing wave having the same frequency and amplitude as that of a noise to reduced but having a reverse phase can be easily obtained, and thus efficient noise reduction can be obtained despite variation of the frequency of the noise.
Inventors
- 👤 Masaaki Nagami
- 👤 Akira Motojima
- 👤 Yoshihiro Kageyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:56
CPC Classifications
H; H03; H03G; H03G9/00; H03G9/005; H03G9/02; H03G9/025; G; G10; G10K; G10K2210/00; G10K2210/10; G10K2210/112
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
288 words
A noise reducing device in which noise is silenced by superposing on an original noise wave generated from a noise wave source a noise silencing wave having a different phase from that of said noise wave and generated from a noise silencing device, said noise silencing device comprising: a) a frequency selecting means for selecting at least one frequency with respect to said noise wave, said frequency selecting means having i) a first and pass filter means comprising a plurality of band pass filters having different pass bands, whereby an electric signal representing said noise wave is separated into a plurality of frequency bands; ii) detecting means for detecting a frequency band in which a peak level of said noise wave exists; b) a delaying means for delaying a phase of said noise wave, said delaying means comprising a plurality of delay circuits connected to said band pass filters to delay said separated electric signal; c) an amplifying means for adjusting a gain of said delayed noise wave, said amplifying means comprising a plurality of amplifying circuits connected to said delay circuits for adjusting the gain to said delayed signal and servicing as a gate circuit; d) factor selecting means for selecting at least one of a delaying factor used for said delaying means and a gain factor used for said amplifying means with respect to said selected frequency; e) controlling means for controlling at least one of said delaying means and amplifying means utilizing said selected delaying factor and gain factor, respectively; f) a processing means for processing at least a signal output from said amplifying circuit to output a noise silencing signal; and g) means for superposing said noise silencing signal on said original noise wave.
Claim 2
Dependent Claim
288 words
A noise reducing device in which noise is silenced by superposing on an original noise wave generated from a noise wave source a noise silencing wave having a different phase from that of said noise wave and generated from a noise silencing device, said noise silencing device comprising: a) a frequency selecting means for selecting at least one frequency with respect to said noise wave, said frequency selecting means having i) a first and pass filter means comprising a plurality of band pass filters having different pass bands, whereby an electric signal representing said noise wave is separated into a plurality of frequency bands; ii) detecting means for detecting a frequency band in which a peak level of said noise wave exists; b) a delaying means for delaying a phase of said noise wave, said delaying means comprising a plurality of delay circuits connected to said band pass filters to delay said separated electric signal; c) an amplifying means for adjusting a gain of said delayed noise wave, said amplifying means comprising a plurality of amplifying circuits connected to said delay circuits for adjusting the gain to said delayed signal and servicing as a gate circuit; d) factor selecting means for selecting at least one of a delaying factor used for said delaying means and a gain factor used for said amplifying means with respect to said selected frequency; e) controlling means for controlling at least one of said delaying means and amplifying means utilizing said selected delaying factor and gain factor, respectively; f) a processing means for processing at least a signal output from said amplifying circuit to output a noise silencing signal; and g) means for superposing said noise silencing signal on said original noise wave.
Claim 3
Dependent Claim
80 words
A noise reducing device according to claim 1, wherein said noise silencing device is further provided with an analog-to-digital converter for converting said original noise to digital electric signal arranged between said noise wave source and said noise silencing device, and a digital-to-analog converter for converting said digitized delayed noise wave output from said delaying means to actual noise signal arranged between said noise silencing device and said superposing means provided in a space through which said noise wave passes.
Claim 4
Dependent Claim
18 words
A noise reducing device according to claim 1, wherein said peak level of said original noise wave varies.
Claim 5
Dependent Claim
25 words
A noise reducing device according to claim 2, wherein said analog-to-digital converter is a microphone which convert said original noise wave to a digital signal.
Claim 6
Dependent Claim
181 words
A noise reducing device according to claim 1, wherein said detecting means for detecting a frequency having a peak level of said noise wave further comprises a second band pass filter means comprising a plurality of band pass filter having different pass bands, whereby said electric signal is separated into a plurality of frequency bands, an averaging means comprising a plurality of averaging circuits connected to said band pass filters in said second band pass filter means for obtaining an average output of said band pass filters in said second band pass filter means, and a means for discriminating at least one band pass filter in which a highest means output thereof exists out of all of said band pass filters, said controlling means for controlling one of said delaying factor and said gain factor of at least one of said amplifying circuits in said amplifying means and said delaying circuit connected o a band pass filter corresponding to the band pass filter in said second band pass filter means in which said mean output thereof shows a highest peak level.
Claim 7
Dependent Claim
29 words
A noise reducing device according to claim 1, wherein said original noise wave source is one of a source selected from an internal combustion engine and an electric motor.
Claim 8
Dependent Claim
37 words
A noise reducing device according to claim 4, wherein said means for superposing said noise silencing signal with said original signal wave is a speaker which is provided in a space through which said noise wave passes.
Claim 9
Dependent Claim
27 words
A noise reducing device according to claim 7, wherein said microphone and speaker are arranged in said space separate from each other with a predetermined length therebetween.
Claim 10
Dependent Claim
22 words
A noise reducing device according to claim 7, wherein both of said microphone and speaker are provided in a gas exhausting pipe.
Claim 11
Dependent Claim
28 words
A noise reducing device according to claim 7, wherein said microphone is provided in a trunk of an automobile while said speaker is provided in a cabin thereof.
Claim 12
Dependent Claim
221 words
A noise reducing device in which noise is silenced by superposing on an original noise wave generated from a noise wave source a noise silencing wave having a different phase from that of said noise wave and generated from a noise silencing device, wherein said noise silencing device comprises: a delaying means for delaying a phase of said noise wave; an amplifying means for adjusting a gain of said delayed noise wave; a frequency selecting means for selecting at least one frequency band having a largest output level from a plurality of frequency bands containing said noise wave; a parameter memory means for previously storing a plurality of delaying factors, each different from each other, and a plurality of gain factors, each different from each other, said delaying and gain factors being determined with respect to a condition of said noise wave source and connected to said frequency selecting means so that when information about the condition of said noise wave source is output from said frequency selecting means, at least one of said delaying factors and at least one of said gain factors stored in said parameter memory means is selected to control at least one of said delaying means and amplifying means, and said amplifying means generating a noise silencing wave to be superposed on said original noise wave.
Claim 13
Dependent Claim
221 words
A noise reducing device in which noise is silenced by superposing on an original noise wave generated from a noise wave source a noise silencing wave having a different phase from that of said noise wave and generated from a noise silencing device, wherein said noise silencing device comprises: a delaying means for delaying a phase of said noise wave; an amplifying means for adjusting a gain of said delayed noise wave; a frequency selecting means for selecting at least one frequency band having a largest output level from a plurality of frequency bands containing said noise wave; a parameter memory means for previously storing a plurality of delaying factors, each different from each other, and a plurality of gain factors, each different from each other, said delaying and gain factors being determined with respect to a condition of said noise wave source and connected to said frequency selecting means so that when information about the condition of said noise wave source is output from said frequency selecting means, at least one of said delaying factors and at least one of said gain factors stored in said parameter memory means is selected to control at least one of said delaying means and amplifying means, and said amplifying means generating a noise silencing wave to be superposed on said original noise wave.
Claim 14
Dependent Claim
119 words
A noise reducing device according to claim 11, wherein said frequency selecting means comprises: a band pass filter means having a plurality of band pass filters, each band pass filter having a different band pass to separate said noise wave into said plurality of frequency bands; an averaging means comprising a plurality of averaging circuits connected to said plurality of band pass filters for obtaining an average output of said band pass filter means; and a discriminating means for discriminating at least one of said plurality of frequency bands having said largest output level among all of said plurality of averaging circuits and outputting said at least one of said plurality of frequency bands to said parameter memory means.
Claim 15
Dependent Claim
64 words
A noise reducing device of claim 11, wherein said frequency selecting means comprises a noise source condition detecting means for detecting a condition of said noise wave source and for outputting a control signal into said parameter memory means to select at lest one of said delay factor and gain factor to adjust at least one of said delaying means and amplifying means, respectively.
Claim 16
Dependent Claim
43 words
A noise reducing device according to claim 13, wherein said noise source condition detecting means for detecting said noise wave source conditions comprises a detecting circuit for detecting a rotation number of a rotating body selected from an electric motor and an engine.
Claim 17
Dependent Claim
68 words
A noise reducing device according to claim 13, wherein said noise source condition detecting means detects a rotation number of a rotating body in said noise wave source and outputs information to said parameter memory means to select one of a delaying factor and gain factor stored therein in accordance with said detected condition and to control at least one of said delaying means and amplifying means, respectively.
Claim 18
Dependent Claim
91 words
A noise reducing device of claim 11, wherein said frequency selecting means comprises: a noise source condition detecting means for detecting a condition of said noise wave source and for outputting a control signal into said parameter memory means to select at least one of said delay factor and gain factor to adjust at least one of said delaying means and amplifying means, respectively; and a signal generating means for generating a signal corresponding to said noise wave into said delaying means based on said condition of said nose wave source.
Claim 19
Dependent Claim
42 words
A noise reducing device according to claim 16, wherein said noise source condition means for detecting said noise wave source conditions comprises a detecting circuit for detecting a rotation number of a rotating body selected from an electric motor and an engine.
Claim 20
Dependent Claim
70 words
A noise reducing device according to claim 16, wherein said noise source condition detecting means detects a rotation number of a rotating body in said noise wave source and outputs information to said parameter memory means to select at least one of a delaying factor and gain factor stored therein in accordance with said detected condition and to control at least one of said delaying means, respectively and amplifying means.
Claim 21
Dependent Claim
73 words
A noise reducing device according to claim 11, further comprising an analog-to-digital converter for converting said original noise to digital electric signal arranged between said noise wave source and said noise silencing device, and a digital-to-analog converter for converting said digitized delayed noise wave output from said delaying means to actual noise signal arranged between said noise silencing device and said superposing means provided in a space through which said noise wave passes.
Claim 22
Dependent Claim
26 words
A noise reducing device according to a claim 19, wherein said analog-to-digital converter is a microphone which converts said original noise wave to a digital signal.
Claim 23
Dependent Claim
36 words
A noise reducing device according to claim 20, wherein said means for superposing said noise signal with said original noise wave is a speaker which is provided in a space through which said noise wave passes.
Claim 24
Dependent Claim
27 words
A noise reducing device according to claim 20, wherein said microphone and speaker are arranged in said space separate from each other with a predetermined length therebetween.
Claim 25
Dependent Claim
22 words
A noise reducing device according to claim 20, wherein both of said microphone and speaker are provided in a gas exhausting pipe.
Claim 26
Dependent Claim
28 words
A noise reducing device according to claim 20, wherein said microphone is provided in a trunk of an automobile while said speaker is provided in a cabin thereof.
Claim 27
Dependent Claim
28 words
A noise reducing device according to claim 11, wherein said original noise wave is one of a source selected from an internal combustion engine and an electric motor.
Claim 28
Dependent Claim
19 words
A noise reducing device according to claim 11, wherein said original noise wave has a peak level which varies.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-03-07 | 1997-09-06 | 1998-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-07 | 2001-09-06 | 2002-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-07 | 2005-09-06 | 2006-03-08 | $7700.00 | Window Closed / Lapsed |