US3815039A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic noise reduction system
Assignee: Panasonic Holdings Corp
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Filing: 1972-04-14
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Granted: 1974-06-04
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Expires: 1992-04-14
Abstract
Abstract An automatic noise reduction system has a signal amplifier, a resistor as a first impedance circuit and a second impedance circuit which comprises resistors, capacitor and a variable resistance element. The frequency response of the second impedance circuit changes according to the resistance value of the variable resistance element and that resistance value is changed by a control circuit. In recording, the resistor constituting the first impedance circuit is connected to the input side of the signal amplifier and the second impedance circuit is connected to the negative feedback loop of the signal amplifier, and the control means provides a D.C. voltage in response to the input signal, so that the signal to be recorded is emphasized. In reproducing, the connection is reversed and the control means provides a D.C. voltage in response to the output signal, so that the reproduced signal is modified with characteristics complementary to the emphasized characteristics and provided with the same wave form as that of the original signal with reduced record medium noises.
Inventors
- 👤 K Fujisawa
- 👤 M Tomita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:22
CPC Classifications
H; H03; H03G; H03G9/00; H03G9/02; H03G9/025
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
328 words
An automatic noise reduction system for a signal handling system which has first and second functions comprising an input terminal, an output terminal, a signal amplifier having an input and an output side, a first impedance means, a second impedance means and two switches each having a first terminal, a second terminal and a common terminal; a first terminal of one switch of said two switches being coupled to said input terminal, a second terminal of said one switch being coupled to said output terminal and a common terminal of said one switch being coupled to one end of said first impedance means, a first terminal of the other switch of said two switches being coupled to said output terminal, a second terminal of said other switch being coupled to said input terminal and a common terminal of said other switch being coupled to one end of said second impedance means, the other end of said first impedance means and said second impedance means being coupled to said input side of said signal amplifier and said output side of said signal amplifier being connected directly to said output terminal; wherein when said common terminals of said two switches are connected to said first terminals, said first impedance means is connected between said input terminal and said input side of said signal amplifier, and said second impedance means is connected between said input and said output sides of said signal amplifier for carying out said first function; and when said common terminals of said two switches are connected to said second terminals, said second impedance means is connected between said input terminal and said input side of said signal amplifier, and said first impedance means is connected between said output terminal and said input side of said signal amplifier for carrying out said second function; whereby the input-output transfer characteristic of said automatic noise reduction system during said first function is substantially complementary to that during said second function.
Claim 2
Dependent Claim
328 words
An automatic noise reduction system for a signal handling system which has first and second functions comprising an input terminal, an output terminal, a signal amplifier having an input and an output side, a first impedance means, a second impedance means and two switches each having a first terminal, a second terminal and a common terminal; a first terminal of one switch of said two switches being coupled to said input terminal, a second terminal of said one switch being coupled to said output terminal and a common terminal of said one switch being coupled to one end of said first impedance means, a first terminal of the other switch of said two switches being coupled to said output terminal, a second terminal of said other switch being coupled to said input terminal and a common terminal of said other switch being coupled to one end of said second impedance means, the other end of said first impedance means and said second impedance means being coupled to said input side of said signal amplifier and said output side of said signal amplifier being connected directly to said output terminal; wherein when said common terminals of said two switches are connected to said first terminals, said first impedance means is connected between said input terminal and said input side of said signal amplifier, and said second impedance means is connected between said input and said output sides of said signal amplifier for carying out said first function; and when said common terminals of said two switches are connected to said second terminals, said second impedance means is connected between said input terminal and said input side of said signal amplifier, and said first impedance means is connected between said output terminal and said input side of said signal amplifier for carrying out said second function; whereby the input-output transfer characteristic of said automatic noise reduction system during said first function is substantially complementary to that during said second function.
Claim 3
Dependent Claim
62 words
An automatic noise reduction system as claimed in claim 1, wherein said first impedance means is a resistor and said second impedance means comprising two resistors connected in series with each other and a bypass circuit means having two terminals, one terminal of which is connected to a junction point of said two resistors and the other terminal of which is grounded.
Claim 4
Dependent Claim
29 words
An automatic noise reduction system as claimed in claim 2, wherein a bypass circuit means comprises a capacitor and a variable resistance means connected in series with each other.
Claim 5
Dependent Claim
20 words
An automatic noise reduction system as claimed in claim 3, wherein said variable resistance means is a field effect transistor.
Claim 6
Dependent Claim
105 words
An automatic noise reduction system as claimed in claim 1 wherein said noise reduction system further comprises a control means which is couPled at one end thereof to said second impedance means and is connected, at another end thereof, to the junction point of said first impedance means and said one of said two switches whereby said second impedance means is supplied with a D.C. voltage related to the input signal to said automatic noise reduction system when said switches are in one position and is supplied with the output signal of said automatic noise reduction system when said switches are in the other position.
Claim 7
Dependent Claim
95 words
An automatic noise reduction system as claimed in claim 5, wherein said control means comprises a series connected high pass filter, an amplifier having an input terminal and an output terminal, a limiter and a rectifier for supplying a D.C. voltage in response to high frequency components of the input signal to said automatic noise reduction system while said switches are in said one position, and also supplying a D.C. voltage in response to high frequency components of the output signal from said automatic noise reduction system while said switches are in said other position.
Claim 8
Dependent Claim
52 words
An automatic noise reduction system as claimed in claim 6 wherein said amplifier in said control means includes a parallel connection of two diodes in reverse polarity to each other, said parallel connection of diodes being connected between said input terminal and said output terminal of said amplifier in said control means.
Claim 9
Dependent Claim
55 words
An automatic noise reduction system as claimed in claim 5 wherein said first impedance means is a resistor and said second impedance means comprises two resistors connected in series with each other and a bypass circuit having one terminal thereof connected to a junction point of said two resistors and the other terminal thereof grounded.
Claim 10
Dependent Claim
38 words
An automatic noise reduction system as claimed in claim 8, wherein said bypass circuit comprises a variable resistance means, the resistance value of which is varied with the change of said D.C. voltage supplied from said control means.
Claim 11
Dependent Claim
28 words
An automatic noise reduction system as claimed in claim 9 wherein said bypass circuit comprises a capacitor and said variable resistance means connected in series with each other.
References Cited (Backward Citations)
US3178698A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |