Patent US2758217A successfully refreshed from Google Patents.
US3902813A
Expired / Lapsed
US
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Automatic gain adjustment for scanning densitometer output device
Assignee: Transidyne General Corp
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Filing: 1974-03-18
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Granted: 1975-09-02
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Expires: 1994-03-18
Abstract
Abstract A densitometer is operative to scan a sample to provide an output voltage proportional to the instantaneous density of the sample. During a first scan of the sample this output is provided to a peak voltage detector so that at the end of the first scan the peak detector contains a voltage proportional to the peak density of the sample. This voltage is applied to an input of a variable gain element so as to adjust the gain to a level which is inversely proportional to the peak voltage. During a second scan, the densitometer output is provided to the gain control element and the output of the element drives a chart recorder. The peak signal recorded during this second scan is thereby adjusted to the maximum scale value of the recorder.
Inventors
- 👤 Broek Jan A Vanden
- 👤 William L Wilfong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:49
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/447; G01N27/44704; G01N27/44717; G01N27/44721; G01N21/00; G01N21/17; G01N21/25; G01N21/27
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
141 words
A system for receiving the output of a scanning densitometer and providing a signal to a display device comprising: a variable gain element; a peak voltage detector having its output connected to an input of a variable gain element so as to control the gain of the element; and switch means operative to connect the output of the densitometer to the peak detector during a first scan of a density record and to connect the output of the densitometer to an input of the variable gain element during a second scan, whereby during the first scan the peak detector assumes a voltage which will cause the variable gain element to output a signal causing the display to generate a full deflection signal at such time as the densitometer signal reached its maximum during a second scan of the same density record.
Claim 2
Independent Claim
141 words
A system for receiving the output of a scanning densitometer and providing a signal to a display device comprising: a variable gain element; a peak voltage detector having its output connected to an input of a variable gain element so as to control the gain of the element; and switch means operative to connect the output of the densitometer to the peak detector during a first scan of a density record and to connect the output of the densitometer to an input of the variable gain element during a second scan, whereby during the first scan the peak detector assumes a voltage which will cause the variable gain element to output a signal causing the display to generate a full deflection signal at such time as the densitometer signal reached its maximum during a second scan of the same density record.
Claim 3
Dependent Claim
95 words
The system of claim 1 wherein during the first scan the densitometer output is connected to the peak detector through a circuit which includes the variable gain element so that the peak detector is charged to a voltage which causes the output of the variable gain element to assume a value which will cause a full deflection of the display unit at occurrence of the peak of the densitometer signal during the second scan, independent of non-linearities in the gain of the variable gain element as a function of its input from the peak detector.
Claim 4
Dependent Claim
22 words
The system of claim 1 wherein the output of the densitometer is directly connected to the peak detector during the first scan.
Claim 5
Dependent Claim
24 words
The system of claim 1 wherein the variable gain element has an output which is inversely proportional to its input from the peak detector.
Claim 6
Dependent Claim
43 words
The system of claim 1 wherein the variable gain element constitutes a transconductance multiplier connected in the feedback path of an operational amplifier so that its gain is inversely proportional to a function of the signal on its input from the peak detector.
Claim 7
Dependent Claim
48 words
The system of claim 1 wherein the switch means operates to connect the peak detector in series with the variable gain element in the feedback loop of an operational amplifier, the operational amplifier having a reference input equal to the desired maximum output of the variable gain circuit.
References Cited (Backward Citations)
US3614241A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |