US3676790A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential feedback amplifier
Assignee: AT&T Inc
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Filing: 1971-06-03
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Granted: 1972-07-11
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Expires: 1991-06-03
Abstract
Abstract The signal at the output of a signal amplifier is compared, in a differential amplifier, with the input signal to the signal amplifier. Any difference between these two voltages causes an error-correcting voltage to be generated across an impedance in series between the signal source and the signal amplifier input port. This error-correcting voltage is added to the input signal in phase to cancel the output signal error. By using a differential amplifier to produce the error signal, there is no feedback to the signal source, resulting in a high degree of stability.
Inventors
- 👤 Henry Richard Beurrier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:02
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/34; H03F1/32; H03F1/3211; H03F2200/00; H03F2200/372
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
109 words
In combination: a signal amplifier; a differential feedback circuit comprising a differential amplifier; means, including a series impedance, for coupling an input signal to said input port of said signal amplifier; means for coupling said input signal to one of the input ports of said differential amplifier; means for coupling a portion of the output signal from said signal amplifier to the other input port of said differential amplifier; and means for coupling the differential output of said differential amplifier across said series impedance to form an error-correcting voltage across said series impedance in response to any difference between said input signal and said portion of amplifier output signal.
Claim 2
Dependent Claim
109 words
In combination: a signal amplifier; a differential feedback circuit comprising a differential amplifier; means, including a series impedance, for coupling an input signal to said input port of said signal amplifier; means for coupling said input signal to one of the input ports of said differential amplifier; means for coupling a portion of the output signal from said signal amplifier to the other input port of said differential amplifier; and means for coupling the differential output of said differential amplifier across said series impedance to form an error-correcting voltage across said series impedance in response to any difference between said input signal and said portion of amplifier output signal.
Claim 3
Dependent Claim
18 words
The combination according to claim 1 wherein equal direct current bias is impressed upon said two active elements.
Claim 4
Dependent Claim
178 words
A differential feedback amplifier including, in combination; a signal source input terminal; an amplifier; and differential feedback means comprising: a series impedance connected between said signal source input terminal and said amplifier input port; a differential amplifier comprising two active elements, each of which includes a control electrode, and emitting electrode and a collecting electrode; means for coupling the control electrode of one of said active elements to said input terminal; means for coupling the collecting electrode of said one active element to tHe junction of said series impedance and said input terminal; means for coupling a portion of the amplifier output signal to the control electrode of the other of said active elements; means for connecting the collecting electrode of said other active element to the junction of said series impedance and said amplifier input port; means for connecting said emitting electrodes to a common impedance; direct current biasing means for impressing a bias across each of said active elements; and a direct current source coupled to the junction of said series impedance and said input terminal.
Claim 5
Dependent Claim
178 words
A differential feedback amplifier including, in combination; a signal source input terminal; an amplifier; and differential feedback means comprising: a series impedance connected between said signal source input terminal and said amplifier input port; a differential amplifier comprising two active elements, each of which includes a control electrode, and emitting electrode and a collecting electrode; means for coupling the control electrode of one of said active elements to said input terminal; means for coupling the collecting electrode of said one active element to tHe junction of said series impedance and said input terminal; means for coupling a portion of the amplifier output signal to the control electrode of the other of said active elements; means for connecting the collecting electrode of said other active element to the junction of said series impedance and said amplifier input port; means for connecting said emitting electrodes to a common impedance; direct current biasing means for impressing a bias across each of said active elements; and a direct current source coupled to the junction of said series impedance and said input terminal.
Claim 6
Dependent Claim
12 words
The combination according to claim 3 wherein said active elements are transistors.
References Cited (Backward Citations)
US3525052A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |