Patent US2008939A successfully refreshed from Google Patents.
Patent US3879135A successfully refreshed from Google Patents.
US3879135A
Expired / Lapsed
US
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Photometer circuitry for the digital indication of the light absorption of a test sample and for automatically obtaining null balance
Assignee: Labtronic AG
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Filing: 1973-04-24
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Granted: 1975-04-22
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Expires: 1993-04-24
Abstract
Abstract In a photometer a reference signal and a signal responsive to the light transmission properties of a test sample are established. Amplifiers expand the difference between the signals to improve measurement accuracy. The signals are then equalized by incrementally increasing one signal by means of a digitalanalog converter. The number of such increments necessary to produce the null balance condition, as recorded in a binary counter, is an indication of the absorption properties of the sample.
Inventors
- 👤 Bruno Egli
- 👤 Niklaus Manser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:33
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/27; G01J; G01J1/00; G01J1/10; G01J1/16; G01J1/1626
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
163 words
Circuitry for the automatic nulling of a photometer comprising: test signal means for providing a first signal in accordance with the light transmission properties of a test sample; comparison signal means for providing a second signal in accordance with a comparison light beam; a first amplifier of controllable amplification coupled to said test signal means for amplifying said first signal; a second amplifier of controllable amplification coupled to said comparison signal means for amplifying said second signal; logic means coupled to said amplifiers for altering the amplification thereof in a first predetermined stepwise manner for amplifying the difference between said first and second signals; signal magnitude adjustment means interposed at the output of one of said amplifiers and receiving one of said signals for altering its magnitude in a second predetermined stepwise fashion into equality with the other of said signals; and a comparator for receiving said first and second signals and for providing an output indicative of the magnitudinal difference between them.
Claim 2
Dependent Claim
163 words
Circuitry for the automatic nulling of a photometer comprising: test signal means for providing a first signal in accordance with the light transmission properties of a test sample; comparison signal means for providing a second signal in accordance with a comparison light beam; a first amplifier of controllable amplification coupled to said test signal means for amplifying said first signal; a second amplifier of controllable amplification coupled to said comparison signal means for amplifying said second signal; logic means coupled to said amplifiers for altering the amplification thereof in a first predetermined stepwise manner for amplifying the difference between said first and second signals; signal magnitude adjustment means interposed at the output of one of said amplifiers and receiving one of said signals for altering its magnitude in a second predetermined stepwise fashion into equality with the other of said signals; and a comparator for receiving said first and second signals and for providing an output indicative of the magnitudinal difference between them.
Claim 3
Dependent Claim
163 words
Circuitry for the automatic nulling of a photometer comprising: test signal means for providing a first signal in accordance with the light transmission properties of a test sample; comparison signal means for providing a second signal in accordance with a comparison light beam; a first amplifier of controllable amplification coupled to said test signal means for amplifying said first signal; a second amplifier of controllable amplification coupled to said comparison signal means for amplifying said second signal; logic means coupled to said amplifiers for altering the amplification thereof in a first predetermined stepwise manner for amplifying the difference between said first and second signals; signal magnitude adjustment means interposed at the output of one of said amplifiers and receiving one of said signals for altering its magnitude in a second predetermined stepwise fashion into equality with the other of said signals; and a comparator for receiving said first and second signals and for providing an output indicative of the magnitudinal difference between them.
Claim 4
Dependent Claim
163 words
Circuitry for the automatic nulling of a photometer comprising: test signal means for providing a first signal in accordance with the light transmission properties of a test sample; comparison signal means for providing a second signal in accordance with a comparison light beam; a first amplifier of controllable amplification coupled to said test signal means for amplifying said first signal; a second amplifier of controllable amplification coupled to said comparison signal means for amplifying said second signal; logic means coupled to said amplifiers for altering the amplification thereof in a first predetermined stepwise manner for amplifying the difference between said first and second signals; signal magnitude adjustment means interposed at the output of one of said amplifiers and receiving one of said signals for altering its magnitude in a second predetermined stepwise fashion into equality with the other of said signals; and a comparator for receiving said first and second signals and for providing an output indicative of the magnitudinal difference between them.
Claim 5
Dependent Claim
29 words
The circuitry of claim 1 wherein the amplifier for said one of said signals has a lower level of amplification than the amplifier for the other of said signals.
Claim 6
Dependent Claim
36 words
The circuit of claim 1 wherein said logic means is further defined interposed between said comparator and said signal magnitude adjustment means for bringing the latter into operation when said comparator senses a predetermined signal magnitude.
Claim 7
Dependent Claim
42 words
The circuitry of claim 1 wherein said logic means provides a coarse stepwise alteration of the amplification of said first and second amplifiers and said signal adjustment means provides a fine stepwise alteration of the signal magnitude of one of said signals.
Claim 8
Dependent Claim
18 words
The circuitry of claim 4 wherein said logic means includes a counter programmed to provide said amplification alteration.
Claim 9
Dependent Claim
42 words
The circuitry of claim 1 wherein said signal adjustment means includes a frequency generator providing digital output signals and a digital-analog converter operable by said frequency generator for incrementally altering the magnitude of said one signal responsive to said digital output signals.
Claim 10
Dependent Claim
48 words
The circuitry of claim 1 wherein said signal adjustment means includes counting means interposed between said frequency generator and said digital-analog converter for recording the magnitude of signal adjustment necessary to produce signal equality thereby to provide an indication of the light transmission properties of the test sample.
Claim 11
Dependent Claim
14 words
The circuitry of claim 1 wherein said signal adjustment means receives said second signal.
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) | 1978-04-21 | 1978-10-21 | 1979-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-21 | 1982-10-21 | 1983-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-21 | 1986-10-21 | 1987-04-22 | $7700.00 | Window Closed / Lapsed |