US3943455A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Analog feedback amplifier employing a four-quadrant integrated circuit multiplier as the active control element
Assignee: United States Department of the Navy
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Filing: 1974-06-03
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Granted: 1976-03-09
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Expires: 1994-06-03
Abstract
Abstract An analog feedback circuit for producing a null or zero output for two eir in-phase or 180° out-of-phase input signals applied to the circuit. The dc control voltage is applied along with the first input signal to a multiplier whose output is summed with the second input signal in an operational amplifier to provide the amplitude and phase of the control voltage.
Inventors
- 👤 Thomas H. Bladen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:08
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
125 words
An analog feedback circuit comprising: a four quadrant multiplier for receiving a first ac analog voltage input signal and a dc control voltage input signal and supplying an output signal; a first summing resistor for receiving said multiplier output signal and providing an analog output therefrom; a second summing resistor for receiving a second analog voltage input signal of either in-phase or 180° out-of-phase relationship with said first analog voltage input signal and for providing an analog output therefrom; means for summing said outputs from said first and second summing resistors; and feedback circuit means coupled between said summing means and said dc control input for continously providing a nulled or zero output from said summing means by controlling said dc control voltage input signal.
Claim 2
Dependent Claim
125 words
An analog feedback circuit comprising: a four quadrant multiplier for receiving a first ac analog voltage input signal and a dc control voltage input signal and supplying an output signal; a first summing resistor for receiving said multiplier output signal and providing an analog output therefrom; a second summing resistor for receiving a second analog voltage input signal of either in-phase or 180° out-of-phase relationship with said first analog voltage input signal and for providing an analog output therefrom; means for summing said outputs from said first and second summing resistors; and feedback circuit means coupled between said summing means and said dc control input for continously providing a nulled or zero output from said summing means by controlling said dc control voltage input signal.
Claim 3
Dependent Claim
26 words
An analog feedback circuit as recited in claim 1 wherein said summing means comprises an operational amplifier, and wherein said feedback circuit includes a phase detector.
Claim 4
Dependent Claim
52 words
An analog feedback circuit as recited in claim 2 further including an operational amplifier coupled between said multiplier and said first summing resistor for converting said multiplier output from a differential output signal to a single ended in-phase or 180° out-of-phase output signal with respect to said first ac analog input voltage.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-09 | 1979-09-08 | 1980-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-09 | 1983-09-08 | 1984-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-09 | 1987-09-08 | 1988-03-09 | $7700.00 | Window Closed / Lapsed |