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US4618834A
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Variable characteristics amplifier circuit
Assignee: Pioneer Corp
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Filing: 1985-07-10
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Granted: 1986-10-21
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Expires: 2005-07-10
Abstract
Abstract A variable characteristics amplifier circuit such as may be used in an inter-music interval detecting circuit for a tape deck, record player, or the like. First and second transistors are connected in an emitter follower configuration with an input signal being applied to the base of the first transistor. One of the emitter or collector of the second transistor is connected through a series circuit of a capacitor and resistor to an inverting input terminal of an operational amplifier, and a feedback circuit is provided between this input terminal and the output of the operational amplifier. A capacitor is coupled between the selected one of the emitter and collector of the second transistor and its base.
Inventors
- 👤 Hiroo Adachi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:49
CPC Classifications
H; H03; H03G; H03G9/00; H03G9/02; H03G9/12; G; G11; G11B; G11B27/00; G11B27/10; G11B27/19; G11B27/22
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
88 words
A variable characteristics amplifier circuit comprising: an active element provided with a pair of controlled terminals and a single controlling terminal and conductive in a forwardly biased state; an amplifier circuit having a feedback circuit coupled between input and output terminals thereof, said input terminal being connected to a selected one of said controlled terminals of said active element; means for selectively reversely biasing said active element in accordance with a characteristics varying command; and an impedance element connected between said one controlled terminal and said controlling terminal.
Claim 2
Dependent Claim
88 words
A variable characteristics amplifier circuit comprising: an active element provided with a pair of controlled terminals and a single controlling terminal and conductive in a forwardly biased state; an amplifier circuit having a feedback circuit coupled between input and output terminals thereof, said input terminal being connected to a selected one of said controlled terminals of said active element; means for selectively reversely biasing said active element in accordance with a characteristics varying command; and an impedance element connected between said one controlled terminal and said controlling terminal.
Claim 3
Dependent Claim
16 words
The variable characteristics amplifier circuit of claim 1, wherein said active element comprises a bipolar transistor.
Claim 4
Dependent Claim
15 words
The variable characteristics amplifier circuit of claim 2, wherein said impedance element comprises a capacitor.
Claim 5
Dependent Claim
36 words
The variable characteristics amplifier circuit of claim 1, further comprising a series circuit of a capacitor and a resistor for connecting said input terminal of said amplifier to said one controlled terminal of said active element.
Claim 6
Dependent Claim
117 words
A variable characteristics amplifier circuit comprising: first and second transistors connected to an emitter follower circuit with an emitter of said first transistor driving a base of said second transistor, an imput signal being applied to a base of said first transistor; a capacitor coupled between a base of said second transistor and an emitter of said second transistor; an operational amplifier having a feedback circuit comprising a parallel circuit of a capacitor and a resistor coupled between an inverting input terminal and an output terminal of said operational amplifier; and a series circuit of a capacitor and a resistor coupled between said inverting input terminal of said operational amplifier and said emitter of said second transistor.
Claim 7
Dependent Claim
117 words
A variable characteristics amplifier circuit comprising: first and second transistors connected to an emitter follower circuit with an emitter of said first transistor driving a base of said second transistor, an imput signal being applied to a base of said first transistor; a capacitor coupled between a base of said second transistor and an emitter of said second transistor; an operational amplifier having a feedback circuit comprising a parallel circuit of a capacitor and a resistor coupled between an inverting input terminal and an output terminal of said operational amplifier; and a series circuit of a capacitor and a resistor coupled between said inverting input terminal of said operational amplifier and said emitter of said second transistor.
Claim 8
Dependent Claim
22 words
The variable characteristics amplifier circuit of claim 5, wherein said collector of said second transistor is connected directly to a voltage source.
Claim 9
Dependent Claim
117 words
A variable characteristics amplifier circuit comprising: first and second transistors connected to an emitter follower circuit with an emitter of said first transistor driving a base of said second transistor, an input signal being applied to a base of said first transistor; a capacitor coupled between a base of said second transistor and a collector of said second transistor; an operational amplifier having a feedback circuit comprising a parallel circuit of a capacitor and a resistor coupled between an inverting input terminal and an output terminal of said operational amplifier; and a series circuit of a capacitor and a resistor coupled between said inverting input terminal of said operational amplifier and said collector of said second transistor.
Claim 10
Dependent Claim
117 words
A variable characteristics amplifier circuit comprising: first and second transistors connected to an emitter follower circuit with an emitter of said first transistor driving a base of said second transistor, an input signal being applied to a base of said first transistor; a capacitor coupled between a base of said second transistor and a collector of said second transistor; an operational amplifier having a feedback circuit comprising a parallel circuit of a capacitor and a resistor coupled between an inverting input terminal and an output terminal of said operational amplifier; and a series circuit of a capacitor and a resistor coupled between said inverting input terminal of said operational amplifier and said collector of said second transistor.
Claim 11
Dependent Claim
20 words
The variable characteristics amplifier circuit of claim 7, further comprising a resistor coupled between said collector and a voltage source.
References Cited (Backward Citations)
US4220931A
Cited
US4178482A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-20 | 1990-04-21 | 1990-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-20 | 1994-04-21 | 1994-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-20 | 1998-04-21 | 1998-10-21 | $7700.00 | Window Closed / Lapsed |