Patent US677895A successfully refreshed from Google Patents.
US4499423A
Expired / Lapsed
US
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Circuit arrangement for correction of a sensor output
Assignee: Draegerwerk AG and Co KGaA
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Filing: 1981-12-08
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Granted: 1985-02-12
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Expires: 2001-12-08
Abstract
Abstract A circuit arrangement is disclosed for correcting the output of a sensor which experiences changes in sensitivity due to the presence of one or more influencing factors, such as the concentration of a material to be sensed, or the passage of time. The circuit arrangement includes a correction network which generates a simulated sensitivity curve which simulated curve is combined with the output of the signal to produce a corrected output signal which has apparent constant sensitivity.
Inventors
- 👤 Hans Matthiessen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:03
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/404; G01N27/4045; G01D; G01D3/00; G01D3/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
135 words
A circuit arrangement for correcting the output of a sensor which experiences time dependent error changes in sensitivity, according to a sensitivity curve, as a function of at least one influence factor comprising: correction circuit means which simulates the sensitivity curve as a function of time and the at least one influence factor, connected to the sensor for receiving the sensor output and for producing from the sensor output a corrected output signal of constant sensitivity, said correction circuit means comprising a differential amplifier having two inputs and an output, one of said inputs being provided with a value corresponding to a sensitivity of the sensor when it is not experiencing a load, the other input provided for receiving a quantity proportional to the sensor output as it is changed according to the sensitivity curve.
Claim 2
Dependent Claim
135 words
A circuit arrangement for correcting the output of a sensor which experiences time dependent error changes in sensitivity, according to a sensitivity curve, as a function of at least one influence factor comprising: correction circuit means which simulates the sensitivity curve as a function of time and the at least one influence factor, connected to the sensor for receiving the sensor output and for producing from the sensor output a corrected output signal of constant sensitivity, said correction circuit means comprising a differential amplifier having two inputs and an output, one of said inputs being provided with a value corresponding to a sensitivity of the sensor when it is not experiencing a load, the other input provided for receiving a quantity proportional to the sensor output as it is changed according to the sensitivity curve.
Claim 3
Dependent Claim
21 words
A circuit arrangement according to claim 1, wherein said correction circuit means includes a digital circuit for simulating the sensitivity curve.
Claim 4
Dependent Claim
37 words
A circuit arrangement according to claim 1, wherein said correction circuit means includes at least one RC element for generating a logarithmic simulated sensitivity curve which corresponds to logarithmic sections of the sensitivity curve of the sensor.
Claim 5
Dependent Claim
77 words
A circuit arrangement according to claim 1, wherein the sensor comprises an electro-chemical sensor for determining alcohol concentration in a gas mixture, the sensitivity curve changing as a function of time and an occuring concentration value of alcohol in the gas mixture, said correction circuit means including means for readjusting a gain of a measuring amplifier for receiving an input quantity occurring as a voltage drop at a load resistance in the circuit of the electro-chemical cell.
Claim 6
Independent Claim
99 words
A method of correcting the output of a sensor which experiences a change in sensitivity that changes in time to a known extent as a function of at least one influence factor comprising: generating a simulated sensitivity curve which simulates the changing sensitivity with time and as a function of the at least one influence factor; combining a value from the sensitivity curve with an actual output value from the sensor at each point in time plotted on the curve to generate a corrected output signal; and providing the corrected output signal as an indicating output of the sensor.
Claim 7
Independent Claim
99 words
A method of correcting the output of a sensor which experiences a change in sensitivity that changes in time to a known extent as a function of at least one influence factor comprising: generating a simulated sensitivity curve which simulates the changing sensitivity with time and as a function of the at least one influence factor; combining a value from the sensitivity curve with an actual output value from the sensor at each point in time plotted on the curve to generate a corrected output signal; and providing the corrected output signal as an indicating output of the sensor.
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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) | 1988-02-12 | 1988-08-13 | 1989-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-12 | 1992-08-13 | 1993-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-12 | 1996-08-13 | 1997-02-12 | $7700.00 | Window Closed / Lapsed |