US3783190A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aperture correction circuit for low light level television camera
Assignee: GTE Sylvania Inc
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Filing: 1971-04-08
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Granted: 1974-01-01
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Expires: 1991-04-08
Abstract
Abstract An aperture correction circuit for a low light level television (LLLTV) camera comprises a transistor differential amplifier having a delay line connected between the transistor base electrodes and a voltage controlled variable resistor, such as a Raysistor, connected between the emitter electrodes of the transistors. The control voltage for the Raysistor is derived from the video signal amplitude or the target control voltage as a measure of the average value of the intensity of light from a viewed scene. The control signal may be obtained from a threshold circuit or from the automatic light control circuit.
Inventors
- 👤 R Gaebele
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:15
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/205; H04N5/208
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
128 words
In a low light level television system having a vidicon with a target plate responsive to the level of light in the ambient scene being viewed and producing output video signals, an aperture correction circuit with first and second transistor amplifiers having base electrodes interconnected by a delay line, means for applying the video signal from the vidicon to the base electrode of the first transistor, and a video output line connected to the collector electrode of said second transistor amplifier, the improvement consisting of a variable resistor interconnecting the emitters of said transistor amplifiers, and means responsive to the ambient light level of said viewed scene for changing the resistance of said variable resistor whereby automatically to disable the aperture correction circuit in low ambient light levels.
Claim 2
Dependent Claim
128 words
In a low light level television system having a vidicon with a target plate responsive to the level of light in the ambient scene being viewed and producing output video signals, an aperture correction circuit with first and second transistor amplifiers having base electrodes interconnected by a delay line, means for applying the video signal from the vidicon to the base electrode of the first transistor, and a video output line connected to the collector electrode of said second transistor amplifier, the improvement consisting of a variable resistor interconnecting the emitters of said transistor amplifiers, and means responsive to the ambient light level of said viewed scene for changing the resistance of said variable resistor whereby automatically to disable the aperture correction circuit in low ambient light levels.
Claim 3
Dependent Claim
41 words
The system according to claim 1 with an automatic light control circuit connected to the video output of said vidicon and having an output, said last named means comprising at least part of said output of the automatic light control circuit.
Claim 4
Dependent Claim
66 words
The system according to claim 1 in which said last named means comprises a threshold detector having an input connected to the video output of said vidicon and prOducing an output when said input thereof exceeds, a predetermined threshold level, means for adjusting the threshold level of said detector, and means responsive to the output of said detector for changing the value of said variable resistor.
Claim 5
Dependent Claim
44 words
The system according to claim 2 in which said variable resistor is responsive to light for changing the value of its resistance, a light emitting element adjacent to said resistor, said element being electrically connected to the output of said automatic light control circuit.
Claim 6
Dependent Claim
50 words
The system according to claim 3 in which said variable resistor is responsive to light for changing the value of its re-sistance, a light emitting element adjacent to said resistor, said light emitting element being responsive to the output of said threshold detector for generating light incident on said resistor.
References Cited (Backward Citations)
US2961574A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |