US3702401A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bridge balancing circuit
Assignee: Lockheed Martin Corp
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Filing: 1968-11-22
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Granted: 1972-11-07
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Expires: 1988-11-22
Abstract
Abstract A bridge balancing circuit is provided, in which errors in a bridge due to relatively slow changes in its parameters or in environmental conditions are substantially eliminated. A receiving means is adapted for coupling to a bridge circuit having a signal source. The receiving means output is coupled through an integrator to an impedance which varies in accordance with the integrator output to thereby balance the bridge with respect to a reference voltage level.
Inventors
- 👤 William J Parkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:38
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/10; G01J5/20; G01J5/22; G01S; G01S3/00; G01S3/78; G01S3/7803
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
107 words
A bridge balancing circuit comprising means for receiving an alternating current signal from said bridge, means coupled to said receiving means for demodulating the output thereof, electrical integrating means switchably coupled to said demodulating means and providing an impedance level control signal, variable impedance means coupled to said integrating means and having an output signal which is coupled to said receiving means, and varies in response to said impedance level control signal, reference signal means coupled to said demodulating means and to said variable impedance means for providing a phase reference signal thereto whereby said bridge circuit may be balanced with respect to a reference voltage level.
Claim 2
Dependent Claim
107 words
A bridge balancing circuit comprising means for receiving an alternating current signal from said bridge, means coupled to said receiving means for demodulating the output thereof, electrical integrating means switchably coupled to said demodulating means and providing an impedance level control signal, variable impedance means coupled to said integrating means and having an output signal which is coupled to said receiving means, and varies in response to said impedance level control signal, reference signal means coupled to said demodulating means and to said variable impedance means for providing a phase reference signal thereto whereby said bridge circuit may be balanced with respect to a reference voltage level.
Claim 3
Dependent Claim
14 words
Apparatus as recited in claim 1 wherein said receiving means comprises a summing amplifier.
Claim 4
Dependent Claim
24 words
Apparatus as recited in claim 1 wherein said demodulating means is a phase sensitive demodulator having a source of phase reference voltage coupled thereto.
Claim 5
Dependent Claim
19 words
Apparatus as recited in claim 1 wherein the output of said electrical integrating means is a direct current voltage.
Claim 6
Dependent Claim
45 words
Apparatus as recited in claim 1 wherein said variable impedance means output signal is an alternating current signal of a phase of 180* from the signal from said bridge and of a frequency and amplitude substantially equal to that of the signal from said bridge.
Claim 7
Dependent Claim
14 words
Apparatus as recited in claim 5 wherein said variable impedance comprises a bi-polar transistor.
Claim 8
Dependent Claim
116 words
Apparatus as recited in claim 1 further including a second demodulating means coupled to the output of said receiving means a second electrical integrating means switchably coupled to said second demodulating means and providing a second impedance level control signal, second variable impedance means coupled to said second integrating means and having an output signal which is coupled to said receiving means and varies in response to said impedance level control signal, and second reference signal means coupled to said second demodulating means and to said second variable impedance means for providing a quadrature phase reference signal thereto whereby the quadrature phase component of said bridge signal is balanced with respect to a reference voltage level.
Claim 9
Dependent Claim
26 words
Apparatus as recited in claim 7 wherein said second demodulating means is a phase sensitive demodulator having a source of quadrature phase reference voltage coupled thereto.
Claim 10
Dependent Claim
43 words
Apparatus as recited in claim 7 wherein said variable impedance means output signal is an alternating current signal of a phase of 180* from that of said bridge signal and of a frequency and amplitude substantially equal to that of said bridge signal.
Claim 11
Dependent Claim
15 words
Apparatus as recited in claim 9 wherein said second variable impedance comprises a bi-polar transistor.
Claim 12
Dependent Claim
56 words
Apparatus as recited in claim 7 wherein said bridge circuit comprises a variable impedance photoelectric detector element the output signal of which comprises a pair of alternating current quadrature phased signals, and said detector element is balanced to substantially zero output signal with respect to a reference voltage level for each of said alternating current signals.
References Cited (Backward Citations)
US3315153A
Cited
US3458770A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-07 | 1976-05-08 | 1976-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-07 | 1980-05-08 | 1980-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-07 | 1984-05-08 | 1984-11-07 | $7700.00 | Window Closed / Lapsed |