US4641344A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Audio equipment
Assignee: Nissan Motor Co Ltd
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Filing: 1985-01-04
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Granted: 1987-02-03
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Expires: 2005-01-04
Abstract
Abstract Audio equipment designed for use at widely varying ambient noise levels allows an audio signal to be amplified to enhanced levels under noisy conditions without added distortion near the high-amplitude end of its dynamic range. Detected or anticipated ambient noise conditions trigger a dynamic range controller to boost the gain of the audio signal to an extent inversely related to the audio signal amplitude. Thus, low-volume audio will be boosted to a great extent while the high-volume end of the dynamic range will experience little or no additional gain. The net effect is two allowable dynamic ranges, both sharing the same high-end volume level but with possibly widely different low-end volume levels. This gain and dynamic range control may also be performed independently on a number of discrete frequency bands. In addition, noise components inherent to the audio signal may be filtered to ambient noise-dependent extends, or the gain boost may be inhibited at volume levels susceptible to such noise.
Inventors
- 👤 Junichi Kasai
- 👤 Hiroshi Imai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:55
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H03G3/32; H03G5/00; H03G5/16; H03G5/165
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
75 words
Audio equipment comprising: (a) means for producing an audio signal; (b) means for detecting the level of noise surrouding the audio equipment; (c) means for controlling a dynamic range of the audio signal in accordance with the detected noise level; (d) means for reproducing the controlled audio signal; and (e) means for filtering high frequency components out of the audio signal to an extent in accordance with the noise level detected by said detection means.
Claim 2
Dependent Claim
75 words
Audio equipment comprising: (a) means for producing an audio signal; (b) means for detecting the level of noise surrouding the audio equipment; (c) means for controlling a dynamic range of the audio signal in accordance with the detected noise level; (d) means for reproducing the controlled audio signal; and (e) means for filtering high frequency components out of the audio signal to an extent in accordance with the noise level detected by said detection means.
Claim 3
Dependent Claim
28 words
The audio equipment according to claim 1, wherein said control means continuously adjusts the effective dynamic range of the audio signal in accordance with the detected noise level.
Claim 4
Dependent Claim
46 words
The audio equipment according to claim 1, wherein said control means controls the dynamic range of the audio signal such that the dynamic range is changed to a predetermined dynamic range value when said detection means detects that the noise level exceeds a predetermined noise level.
Claim 5
Dependent Claim
44 words
The audio equipment according to claim 1, wherein said detection means comprises a microphone disposed near the audio equipment and a control signal generator for converting an output of the microphone into a control signal and sending the control signal to said control means.
Claim 6
Dependent Claim
101 words
The audio equipment according to claim 1, wherein said detection means comprises other elements including a vehicle speed sensor, an engine speed sensor, an air conditioner fan speed switch, a door window opening angle sensor, a road surface monitor, a steering angle sensor, a tunnel-passage detector, wiper operation sensor, and a noise estimating means, said estimating means operable for estimating the noise level on the basis of data outputs from the other elements of said detection means, and a control signal generator for converting the estimated noise level into a control signal and sending the control signal to said control means.
Claim 7
Dependent Claim
17 words
The audio equipment according to claim 3, wherein the predetermined dynamic range width is approximately 40 dB.
Claim 8
Dependent Claim
147 words
The audio equipment according to claim 4, wherein said control means comprises a limiter connected to said audio signal producing means for limiting the audio signal level when said detection means detects that the noise level exceeds a predetermined value, a root-mean-square calculation circuit for calculating an average effective value of the limited audio signal and outputting a signal indicative of the average value, a calculation circuit which receives the output signal of the root-mean-square calculation circuit and said control signal for calculating X 1/ α, where α is the control signal value and X is the average effective value, an adder for adding the output result of the calculation circuit and said control signal, and a gain controller which receives the limited audio signals from said limiter and the output of said adder and controls the gain of the audio signal according to the adder output.
Claim 9
Dependent Claim
36 words
The audio equipment according to claim 1, wherein said reproducing means comprises a preamplifier, a main amplifier, a speaker connected to said main amplifier, and another speaker connected via said control means to said main amplifier.
Claim 10
Dependent Claim
35 words
The audio equipment according to claim 1, wherein said filtering means comprises a controlled low-pass filter connected to said detection means which filters out high-frequency components when the detected noise level exceeds a predetermined level.
Claim 11
Dependent Claim
80 words
The audio equipment according to claim 1, which further comprises means connected between said producing means and said reproducing means for dividing the audio signal into a plurality of signal components, each falling within one of a plurality of frequency bands and wherein said control means comprises a plurality of dynamic range controllers connected for output from said dividing means, each controlling a gain of the corresponding signal component in accordance with the noise level detected by said detection means.
Claim 12
Dependent Claim
36 words
The audio equipment according to claim 10, which further comprises a mixer for mixing the signal components from all of the dynamic range controllers into an audio output signal to be reproduced by said reproducing means.
Claim 13
Dependent Claim
36 words
The audio equipment according to claim 10, which further comprises a plurality of multipliers each connected between said detection means and a corresponding dynamic range controller for multiplying the detected noise level by a constant number.
Claim 14
Dependent Claim
94 words
The audio equipment according to claim 10, which further comprises means for dividing the noise level signal detected and outputted by said detection means into a plurality of noise signal components, each falling within one of a plurality of frequency bands and a plurality of control signal generators for converting corresponding noise signal components from said dividing means into corresponding control signals and sending said control signal to a corresponding dynamic range controller so that the dynamic range of each frequency band of the audio signal the noise level in the same frequency band.
Claim 15
Dependent Claim
135 words
Audio equipment comprising: (a) means for producing an audio signal; (b) means for detecting the level of noise surrounding the audio equipment; (c) means for controlling a dynamic range of the audio signal in accordance with the detected noise level; and (d) means for reproducing the controlled audio signal; (e) said control means operable for continuously adjusting the effective dynamic range of the audio signal in accordance with the detected noise level, (f) said control means further operable for controlling the dynamic range of the audio signal in such a way that an amplification gain factor applied to the audio signal remains constant at a maximum audio signal level and that the gain at the audio signal levels below the maximum increases as the detected noise level increases and as the audio signal level decreases.
Claim 16
Dependent Claim
135 words
Audio equipment comprising: (a) means for producing an audio signal; (b) means for detecting the level of noise surrounding the audio equipment; (c) means for controlling a dynamic range of the audio signal in accordance with the detected noise level; and (d) means for reproducing the controlled audio signal; (e) said control means operable for continuously adjusting the effective dynamic range of the audio signal in accordance with the detected noise level, (f) said control means further operable for controlling the dynamic range of the audio signal in such a way that an amplification gain factor applied to the audio signal remains constant at a maximum audio signal level and that the gain at the audio signal levels below the maximum increases as the detected noise level increases and as the audio signal level decreases.
Claim 17
Dependent Claim
30 words
The audio equipment according to claim 14, wherein the maximum audio signal level results in a sound pressure level of approximately 100 dB when reproduced acoustically by said reproduction means.
Claim 18
Dependent Claim
118 words
Audio equipment for a passenger compartment of an automotive vehicle, comprising: (a) means for producing and amplifying an audio signal; (b) means for detecting the noise level within the passenger compartment and outputting a signal indicative thereof; (c) means for converting the noise level signal from said detecting means into a control signal; (d) means for controlling the dynamic range of the amplified audio signal in accordance with the control signal; and (e) means for reproducing the audio signal whose dynamic range is controlled by said controlling means; (f) said control means operable for continuously adjusting the amplification gain of the audio signal when the audio signal level from said means for producing exceeds a predetermined decibel value.
Claim 19
Dependent Claim
118 words
Audio equipment for a passenger compartment of an automotive vehicle, comprising: (a) means for producing and amplifying an audio signal; (b) means for detecting the noise level within the passenger compartment and outputting a signal indicative thereof; (c) means for converting the noise level signal from said detecting means into a control signal; (d) means for controlling the dynamic range of the amplified audio signal in accordance with the control signal; and (e) means for reproducing the audio signal whose dynamic range is controlled by said controlling means; (f) said control means operable for continuously adjusting the amplification gain of the audio signal when the audio signal level from said means for producing exceeds a predetermined decibel value.
Claim 20
Dependent Claim
33 words
The audio equipment according to claim 16, wherein said controls means controls the amplification gain of the audio signal such that the amplified audio signal level does not exceed a predetermined maximum value.
Claim 21
Dependent Claim
28 words
The audio equipment according to claim 16, wherein said control means selects one of a plurality of change of predetermined dynamic ranges in accordance with the noise level.
Claim 22
Dependent Claim
38 words
The audio equipment according to claim 16, wherein said control means controls the dynamic range of the audio signal in such a way that the amplification gain of the audio signal varies inversely with the audio signal level.
Claim 23
Dependent Claim
16 words
The audio equipment according to claim 16, wherein said predetermined value is substantially minus 40 dB.
Claim 24
Dependent Claim
15 words
The audio equipment according to claim 17, wherein said maximum value is approximately 100 dB.
Claim 25
Dependent Claim
30 words
The audio equipment according to claim 19, wherein said reproducing means is an acoustical speaker and said maximum audio signal level value results in an output of approximately 100 dB.
Claim 26
Dependent Claim
38 words
The audio equipment according to claim 19, wherein said audio signal producing and amplifying means comprises a cassette deck and further comprising means for filtering high-frequency components out of the audio signal in accordance with the noise level.
Claim 27
Dependent Claim
77 words
Audio equipment for the passenger compartment of a vehicle comprising: (a) means for producing and amplifying an audio signal; (b) means for dividing the audio signal into a plurality of frequency bands; (c) means for detecting the noise level within the passenger compartment and outputting a signal indicative thereof; and (d) means for controlling the individual dynamic ranges of the audio frequency bands in accordance with the detected noise level of the signal from said detecting means.
Claim 28
Dependent Claim
77 words
Audio equipment for the passenger compartment of a vehicle comprising: (a) means for producing and amplifying an audio signal; (b) means for dividing the audio signal into a plurality of frequency bands; (c) means for detecting the noise level within the passenger compartment and outputting a signal indicative thereof; and (d) means for controlling the individual dynamic ranges of the audio frequency bands in accordance with the detected noise level of the signal from said detecting means.
Claim 29
Dependent Claim
61 words
The audio equipment according to claim 24, which further comprises means for dividing the signal indicative of the noise level into a plurality of frequency bands matching the audio frequency bands and wherein said control means controls the individual dynamic ranges of the audio signal components in accordance with the noise level in the corresponding frequency band of the noise signal.
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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) | 1990-02-02 | 1990-08-04 | 1991-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-02 | 1994-08-04 | 1995-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-02 | 1998-08-04 | 1999-02-03 | $7700.00 | Window Closed / Lapsed |