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US3886786A
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Null memory system for a gas analysis system
Assignee: ALCOHOL COUNTERMEASURE SYSTEMS CORP
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Filing: 1971-09-20
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Granted: 1975-06-03
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Expires: 1991-09-20
Abstract
Abstract A null memory system is provided for gas testing systems of the type that produce a d.c. signal whose maximum amplitude is indicative of the alcohol concentration of a sample in which an initial, just prior to test, output of the gas detector is automatically taken and that d.c. signal stored in a holding amplifier with which the sample''s output is compared, to counter detector drift and to obviate meter nulling.
Inventors
- 👤 Joseph P Hoppesch
- 👤 Donald H Ward
- 👤 James R Tomashek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:35
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/483; G01N33/497; G01N33/4972; G01D; G01D18/00; G01D18/002
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
128 words
In a gas tester of the type having a detector which receives gas samples and produces a d.c. signal whose maximum amplitude during a period of exposure to a sample is a function of certain gases contained in those samples, the improvement comprising: means for storing and continuously reproducing over a period a single amplitude d.c. signal; means for generating a reference d.c. amplitude signal from the detector just prior to the introduction of a sample of gas to be tested therein and for storing that generated reference signal on said signal storing means; and means coupled to said signal storage means and to the detector for producing an output proportional to the difference in the outputs thereof, whereby drift is minimized and accuracy of output is increased.
Claim 2
Dependent Claim
128 words
In a gas tester of the type having a detector which receives gas samples and produces a d.c. signal whose maximum amplitude during a period of exposure to a sample is a function of certain gases contained in those samples, the improvement comprising: means for storing and continuously reproducing over a period a single amplitude d.c. signal; means for generating a reference d.c. amplitude signal from the detector just prior to the introduction of a sample of gas to be tested therein and for storing that generated reference signal on said signal storing means; and means coupled to said signal storage means and to the detector for producing an output proportional to the difference in the outputs thereof, whereby drift is minimized and accuracy of output is increased.
Claim 3
Dependent Claim
128 words
In a gas tester of the type having a detector which receives gas samples and produces a d.c. signal whose maximum amplitude during a period of exposure to a sample is a function of certain gases contained in those samples, the improvement comprising: means for storing and continuously reproducing over a period a single amplitude d.c. signal; means for generating a reference d.c. amplitude signal from the detector just prior to the introduction of a sample of gas to be tested therein and for storing that generated reference signal on said signal storing means; and means coupled to said signal storage means and to the detector for producing an output proportional to the difference in the outputs thereof, whereby drift is minimized and accuracy of output is increased.
Claim 4
Dependent Claim
128 words
In a gas tester of the type having a detector which receives gas samples and produces a d.c. signal whose maximum amplitude during a period of exposure to a sample is a function of certain gases contained in those samples, the improvement comprising: means for storing and continuously reproducing over a period a single amplitude d.c. signal; means for generating a reference d.c. amplitude signal from the detector just prior to the introduction of a sample of gas to be tested therein and for storing that generated reference signal on said signal storing means; and means coupled to said signal storage means and to the detector for producing an output proportional to the difference in the outputs thereof, whereby drift is minimized and accuracy of output is increased.
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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) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |