US3783393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drift-compensated analog hold circuit
Assignee: Fischer and Porter Co
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Filing: 1972-05-25
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Granted: 1974-01-01
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Expires: 1992-05-25
Abstract
Abstract An analog integral hold circuit adapted to provide a control signal to the valve of a process control system in order to hold the valve position, the circuit being drift free. The drift-free circuit is constituted by an analog hold circuit having integrating characteristics, the output thereof being converted into digital signals that are counted by a variation-detecting circuit. The output of the variation detecting circuit is applied to a feedback circuit that delivers a compensating signal to the input of the analog hold circuit to obviate drift effects.
Inventors
- 👤 H Kakiura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:54
CPC Classifications
G; G11; G11C; G11C27/00; G11C27/02; G11C27/024; G11C27/026
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
175 words
A drift-compensated analog hold circuit comprising: a an analog hold circuit having integrating characteristics and producing an output voltage in response to an input signal b a digitalizing circuit converting the output voltage of said analog hold circuit to digital signals, said circuit including a pulse generator producing periodic pulses, a gate coupled to said analog hold circuit and to said pulse generator, said gate being rendered open periodically by said pulses, and a voltageto-frequency converter coupled to said gate to convert the output voltage passed By said gate into relatively highfrequency pulses whose frequency depends on said voltage, c a variation detecting circuit counting the output of said digitalizing circuit and thereupon detecting the variation of said digital signals, said detecting circuit being constituted by a binary counter coupled to the output of said converter and reset after each counting operation by a pulse from said generator, and d a feedback circuit receiving the output of said variation detecting circuit and delivering a compensation signal to the input circuit of said analog hold circuit.
Claim 2
Dependent Claim
175 words
A drift-compensated analog hold circuit comprising: a an analog hold circuit having integrating characteristics and producing an output voltage in response to an input signal b a digitalizing circuit converting the output voltage of said analog hold circuit to digital signals, said circuit including a pulse generator producing periodic pulses, a gate coupled to said analog hold circuit and to said pulse generator, said gate being rendered open periodically by said pulses, and a voltageto-frequency converter coupled to said gate to convert the output voltage passed By said gate into relatively highfrequency pulses whose frequency depends on said voltage, c a variation detecting circuit counting the output of said digitalizing circuit and thereupon detecting the variation of said digital signals, said detecting circuit being constituted by a binary counter coupled to the output of said converter and reset after each counting operation by a pulse from said generator, and d a feedback circuit receiving the output of said variation detecting circuit and delivering a compensation signal to the input circuit of said analog hold circuit.
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) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |