US3566088A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Analogue correlator with constant signal-to-noise ratio
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1969-08-22
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Granted: 1971-02-23
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Expires: 1989-08-22
Abstract
Abstract An improved analogue correlator wherein the output of a multiplier is fed into a nonlinear amplifier having a feedback network which may contain a capacitor and in which the impedance and time constant increases for an output that is decreasing, thereby increasing the gain of the amplifier while also increasing the time constant of the amplifier by a second order in the presence of the capacitor. Because the time constant of the amplifier increases faster than the signal-to-noise input decreases, the signal-to-noise output from the amplifier gets better for low level signals and can be adjusted to maintain a substantially constant ratio over a relatively large range of input signals.
Inventors
- 👤 Gaines M Crook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:38
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/19; G06G7/1928
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
144 words
A signal correlator providing a substantially constant signal-to-noise ratio of two noiselike input signals to be correlatEd to determine, for example, a common signal origin, said correlator comprising: a. a multiplier responsive to the two input signals to be correlated, said multiplier providing a multiplied signal; and b. a nonlinear operational amplifier coupled to said multiplier for providing an output signal, said operational amplifier having a feedback path including a capacitor in parallel with a first set of serially connected diodes, and a second set of serially connected diodes in parallel with said first set of diodes and said capacitor, said first set of diodes providing a first unidirectional current path, while said second set of diodes provides another unidirectional path opposite to said first current path, whereby the gain of said operational amplifier varies inversely proportional to the magnitude of said output signal.
Claim 2
Dependent Claim
144 words
A signal correlator providing a substantially constant signal-to-noise ratio of two noiselike input signals to be correlatEd to determine, for example, a common signal origin, said correlator comprising: a. a multiplier responsive to the two input signals to be correlated, said multiplier providing a multiplied signal; and b. a nonlinear operational amplifier coupled to said multiplier for providing an output signal, said operational amplifier having a feedback path including a capacitor in parallel with a first set of serially connected diodes, and a second set of serially connected diodes in parallel with said first set of diodes and said capacitor, said first set of diodes providing a first unidirectional current path, while said second set of diodes provides another unidirectional path opposite to said first current path, whereby the gain of said operational amplifier varies inversely proportional to the magnitude of said output signal.
Claim 3
Dependent Claim
166 words
A signal correlator providing a substantially constant signal-to-noise ratio of two noiselike input signals to be correlated, said correlator comprising: a. a multiplier responsive to the two input signals to be correlated, said multiplier providing a product signal; and b. a variable integrator comprising an operational amplifier coupled to said multiplier for providing an output signal, said operational amplifier including a feedback circuit for feeding back a portion of said output signal to the input of said operational amplifier, said feedback circuit comprising a capacitor, a first plurality of diodes serially connected, said first plurality of diodes in parallel with said capacitor and providing a first substantially unidirectional current path, and a second plurality of diodes serially connected, said second plurality of diodes in parallel with said capacitor and said first diodes and providing a second substantially unidirectional current path opposite to said first current path, whereby both the time constant and the gain of said amplifier inversely vary with the magnitude of said input signal.
Claim 4
Dependent Claim
166 words
A signal correlator providing a substantially constant signal-to-noise ratio of two noiselike input signals to be correlated, said correlator comprising: a. a multiplier responsive to the two input signals to be correlated, said multiplier providing a product signal; and b. a variable integrator comprising an operational amplifier coupled to said multiplier for providing an output signal, said operational amplifier including a feedback circuit for feeding back a portion of said output signal to the input of said operational amplifier, said feedback circuit comprising a capacitor, a first plurality of diodes serially connected, said first plurality of diodes in parallel with said capacitor and providing a first substantially unidirectional current path, and a second plurality of diodes serially connected, said second plurality of diodes in parallel with said capacitor and said first diodes and providing a second substantially unidirectional current path opposite to said first current path, whereby both the time constant and the gain of said amplifier inversely vary with the magnitude of said input signal.
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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) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |