Patent US3704432A successfully refreshed from Google Patents.
US3704432A
Expired / Lapsed
US
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Capacitive coulometer improvements
Assignee: Curtis Instruments Inc
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Filing: 1971-07-21
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Granted: 1972-11-28
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Expires: 1991-07-21
Abstract
Abstract A generator utilizing a capacitive coulometer for generating a signal that is inversely proportional to the integral of a selected function. A current source and a variable amplitude interrogation oscillator are connected to the input terminals of a coulometer which modulates the output of the oscillator in accordance with the integral of the current from the current source. The modulated signal is amplified in an AC amplifier and demodulated by a standard envelope detector. The demodulated signal is compared with a reference signal in a differential amplifier which generates an error output signal when the demodulated signal is not equal to the reference signal. The error signal is fed back in a negative feedback path to adjust the amplitude of the variable amplitude interrogation oscillator.
Inventors
- 👤 Eugene P Finger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:45
CPC Classifications
G; G01; G01R; G01R22/00; G01R22/02; G01R31/00; G01R31/36
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
85 words
A generator comprising a variable amplitude oscillator, means for generating a selected electrical function, means for modulating the output of said oscillator by the integral of said function, means for demodulating said modulated signal, said demodulated signal having an amplitude that is proportional to the envelope of the output of said oscillator multiplied by the integral of said function, and negative feedback means for adjusting the amplitude of the output of said oscillator when said demodulated signal is unequal to a preset reference voltage level.
Claim 2
Dependent Claim
85 words
A generator comprising a variable amplitude oscillator, means for generating a selected electrical function, means for modulating the output of said oscillator by the integral of said function, means for demodulating said modulated signal, said demodulated signal having an amplitude that is proportional to the envelope of the output of said oscillator multiplied by the integral of said function, and negative feedback means for adjusting the amplitude of the output of said oscillator when said demodulated signal is unequal to a preset reference voltage level.
Claim 3
Dependent Claim
64 words
The generator of claim 1 wherein said means for adjusting the amplitude of the output of said oscillator comprises a source of reference voltage, means for comparing said reference voltage with said demodulated signal, and means for connecting the output of said comparing means to said variable amplitude oscillator, said output of said comparing means controlling the amplitude of the output of said oscillator.
Claim 4
Dependent Claim
19 words
The generator of claim 2 wherein said means for modulating the output of said oscillator comprises a coulometer integrator.
Claim 5
Dependent Claim
53 words
The generator of claim 3 wherein said coulometer integrator comprises an output capacitance, means for varying said output capacitance in accordance with the integral of said electric function, means for electrically connecting the output of said variable amplitude oscillator to said coulometer, and means for detecting said oscillator output across said output capacitance.
Claim 6
Dependent Claim
21 words
The generator of claim 4 wherein said means for comparing said reference voltage with said demodulated signal is a differential amplifier.
Claim 7
Independent Claim
78 words
A method of generating an electrical function having an amplitude that is inversely proportional to the integral of an electrical function comprising the steps of generating a selected electrical function, generating an AC signal having a controllable amplitude, modulating said AC signal with the integral of said function, demodulating said modulated signal, subtracting said demodulated signal from a reference potential, and adjusting the amplitude of said AC signal when said demodulated signal is unequal to said reference potential.
Claim 8
Independent Claim
78 words
A method of generating an electrical function having an amplitude that is inversely proportional to the integral of an electrical function comprising the steps of generating a selected electrical function, generating an AC signal having a controllable amplitude, modulating said AC signal with the integral of said function, demodulating said modulated signal, subtracting said demodulated signal from a reference potential, and adjusting the amplitude of said AC signal when said demodulated signal is unequal to said reference potential.
Claim 9
Dependent Claim
55 words
The method of claim 6 wherein said modulating step further comprises conducting said AC signal and said electrical function through a liquid metal column in a coulometer, varying the output capacitance of said coulometer in accordance with the integral of said electrical function, and detecting said AC signal across said output capacitance of said coulometer.
References Cited (Backward Citations)
US3255413A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-28 | 1976-05-29 | 1976-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-28 | 1980-05-29 | 1980-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-28 | 1984-05-29 | 1984-11-28 | $7700.00 | Window Closed / Lapsed |