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Patent US4257009A successfully refreshed from Google Patents.
US4257009A
Expired / Lapsed
US
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Inhibit circuit for a differential amplifier
Assignee: RCA Corp
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Filing: 1979-05-23
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Granted: 1981-03-17
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Expires: 1999-05-23
Abstract
Abstract The outputs of a pair of non-additive combiners are coupled to respective inputs of a differential amplifier and an a.c. signal to be amplified is applied to a selected input of one of the combiners. A control circuit operates in a first mode to apply control voltages to the combiner inputs for causing the one combiner to block the a.c. signal and also causing both combiners to apply a common mode input voltage of a first value to the amplifier inputs. In a second mode, the control circuit changes the values of the control voltages in a sense to cause the one combiner to pass the a.c. signal and to also cause both combiners to apply a common mode input voltage of a second value to the amplifier inputs whereby, in either mode, the amplifier produces a constant quiescent d.c. output voltage.
Inventors
- 👤 Bernard J. Yorkanis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:08
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/72
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
152 words
An inhibit circuit for a differential amplifier, comprising: a pair of non-additive combiners, each having an output connected to a respective input of said amplifier; input means for selectively coupling a signal to be amplified to a given input terminal of one of said combiners; a bias controller having a first output for producing a fixed bias voltage and a second output for producing a variable bias voltage, said bias controller having an input responsive to a control signal supplied thereto for controlling the polarity of said variable bias voltage relative to said fixed bias voltage; first means for applying said variable bias voltage to a first input of each of said combiners; second means for applying said fixed bias voltage to a second input of one of said combiners; and a feedback resistor connected between said output of said differential amplifier and said second input of said other of said combiners.
Claim 2
Dependent Claim
152 words
An inhibit circuit for a differential amplifier, comprising: a pair of non-additive combiners, each having an output connected to a respective input of said amplifier; input means for selectively coupling a signal to be amplified to a given input terminal of one of said combiners; a bias controller having a first output for producing a fixed bias voltage and a second output for producing a variable bias voltage, said bias controller having an input responsive to a control signal supplied thereto for controlling the polarity of said variable bias voltage relative to said fixed bias voltage; first means for applying said variable bias voltage to a first input of each of said combiners; second means for applying said fixed bias voltage to a second input of one of said combiners; and a feedback resistor connected between said output of said differential amplifier and said second input of said other of said combiners.
Claim 3
Dependent Claim
103 words
An inhibit circuit for a differential amplifier as recited in claim 8 wherein said bias controller comprises: a potential divider across which a supply voltage is applied, said potential divider having an output tap; a Darlington connection of first and second transistors, the first transistor having a control electrode connected to said tap and an output electrode connected to the control electrode of the second transistor; means for coupling the output electrode of the second resistor to said first output of said bias controller; and means for coupling the output electrode of the first transistor to said second output of said bias controller.
References Cited (Backward Citations)
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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) | 1984-03-16 | 1984-09-15 | 1985-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-16 | 1988-09-15 | 1989-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-16 | 1992-09-15 | 1993-03-17 | $7700.00 | Window Closed / Lapsed |