US3705328A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic zooming in video cameras by control of the deflection system
Assignee: AT&T Inc
•
Filing: 1970-05-01
•
Granted: 1972-12-05
•
Expires: 1990-05-01
Abstract
Abstract Circuitry is disclosed for providing manually controlled electronic size variation (zooming) of the scanned raster in television camera systems. A single control provides a zoom signal which is applied independently to the horizontal and vertical deflection circuits. The zoom signal simultaneously affects the amplitudes of both sweep signals so that the area of the target which is scanned (raster area) maintains a constant aspect ratio while the size of the raster may be varied by the single control. An area of constant size is used to display the video signals for all camera raster sizes, and zooming is achieved when a portion of the image formed on the camera target is reproduced on the full size display.
Inventors
- 👤 Gabor Peter Torok
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:53
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/22; H04N3/223; H04N5/00; H04N5/222; H04N5/262; H04N5/2628
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
252 words
In a video camera system, deflection circuitry for controlling the scan pattern of an electron beam across a target comprising: orthogonal horizontal and vertical deflection yokes for directing the scan pattern of the electron beam in response to current through the yokes, horizontal deflection means for producing a horizontal sweep current and for applying the horizontal sweep current to said horizontal yoke, vertical deflection means for producing a vertical sweep current and for applying the vertical sweep current to said vertical yoke, zoom adjusting means connected to each of said deflection means for simultaneously applying a common dc zoom voltage to each of the deflection means to control the amplitudes of both sweep currents over a continuous range so that the electron beam may be adjusted to scan rasters of different sizes, each having the same selected aspect ratio, both said vertical and horizontal deflection means including respectively vertical and horizontal sweep generators which both include a capacitor, a constant current source for charging said capacitor, the voltage produced by said current source having an amplitude controlled by the common dc zoom voltage, and trigger means for periodically discharging said capacitor to a variable dc voltage level to produce a periodic ramp voltage, and said vertical sweep generator further including a voltage divider for attenuating the common dc zoom voltage to compensate for variations of the dc component of the ramp voltage to maintain the dc component constant with changes in the vertical sweep amplitude caused by the common dc zoom voltage.
Claim 2
Dependent Claim
252 words
In a video camera system, deflection circuitry for controlling the scan pattern of an electron beam across a target comprising: orthogonal horizontal and vertical deflection yokes for directing the scan pattern of the electron beam in response to current through the yokes, horizontal deflection means for producing a horizontal sweep current and for applying the horizontal sweep current to said horizontal yoke, vertical deflection means for producing a vertical sweep current and for applying the vertical sweep current to said vertical yoke, zoom adjusting means connected to each of said deflection means for simultaneously applying a common dc zoom voltage to each of the deflection means to control the amplitudes of both sweep currents over a continuous range so that the electron beam may be adjusted to scan rasters of different sizes, each having the same selected aspect ratio, both said vertical and horizontal deflection means including respectively vertical and horizontal sweep generators which both include a capacitor, a constant current source for charging said capacitor, the voltage produced by said current source having an amplitude controlled by the common dc zoom voltage, and trigger means for periodically discharging said capacitor to a variable dc voltage level to produce a periodic ramp voltage, and said vertical sweep generator further including a voltage divider for attenuating the common dc zoom voltage to compensate for variations of the dc component of the ramp voltage to maintain the dc component constant with changes in the vertical sweep amplitude caused by the common dc zoom voltage.
Claim 3
Dependent Claim
197 words
In a video camera system, deflection circuitry for controlling the scan pattern of an electron beam across a target comprising: orthogonal horizontal and vertical deflection yokes for directing the scan pattern of the electron beam in response to current through the yokes, horizontal deflection means for producing a horizontal sweep current and for applying the horizontal sweep current to said horizontal yoke, vertical deflection means for producing a vertical sweep current and for applying the vertical sweep current to said vertical yoke, zoom adjusting means connected to each of said deflection means for simultaneously applying a common dc zoom voltage to each of the deflection means to control the amplitudes of both sweep currents over a continuous range so that the electron beam may be adjusted to scan rasters of differing sizes, each having the same selected aspect ratio, and at least one of said deflection means including an operational amplifier and a current feedback path from the corresponding yoke to the negative input of said amplifier, and position adjusting means for applying a variable dc positioning voltage to the feedback path to cause a dc shift in the sweep current produced by said one deflection means.
Claim 4
Dependent Claim
197 words
In a video camera system, deflection circuitry for controlling the scan pattern of an electron beam across a target comprising: orthogonal horizontal and vertical deflection yokes for directing the scan pattern of the electron beam in response to current through the yokes, horizontal deflection means for producing a horizontal sweep current and for applying the horizontal sweep current to said horizontal yoke, vertical deflection means for producing a vertical sweep current and for applying the vertical sweep current to said vertical yoke, zoom adjusting means connected to each of said deflection means for simultaneously applying a common dc zoom voltage to each of the deflection means to control the amplitudes of both sweep currents over a continuous range so that the electron beam may be adjusted to scan rasters of differing sizes, each having the same selected aspect ratio, and at least one of said deflection means including an operational amplifier and a current feedback path from the corresponding yoke to the negative input of said amplifier, and position adjusting means for applying a variable dc positioning voltage to the feedback path to cause a dc shift in the sweep current produced by said one deflection means.
Claim 5
Dependent Claim
42 words
A video camera system as claimed in claim 2 wherein associated with said position adjusting means is means for attenuating the variable dc positioning voltage proportionally with the variation of said zoom adjusting means so that the position adjustment is range limited.
Claim 6
Dependent Claim
54 words
A video camera system as claimed in claim 2 wherein said position adjusting means includes a positioning potentiometer, the wiper of whiCh provides the variable dc positioning voltage, and means for restricting the voltage across said potentiometer in proportion to the change of amplitude of the sweep currents provided by said zoom adjusting means.
Claim 7
Dependent Claim
219 words
Electronic zooming apparatus for a video camera system comprising: a solid-state target on which an image is formed, means for producing an electron beam, horizontal deflection means for producing a horizontal sweep signal for periodically shifting the electron beam to scan the target in a horizontal direction, vertical deflection means for producing a vertical sweep signal for periodically shifting the electron beam to scan said target in a vertical direction, said horizontal and vertical deflection means each comprising a sweep generator, said sweep generators both including a capacitor, a constant current source for charging said capacitor, and trigger means for periodically discharging said capacitor to a variable dc voltage level to produce a periodic ramp voltage, adjusting means for producing a dc zoom voltage and for simultaneously applying said dc zoom voltage to each of said deflection means to simultaneously control the voltage produced by each of said constant current sources over a continuous range so that the electron beam may scan rasters of different sizes, each having the same aspect ratio, and said vertical sweep generator further including a voltage divider for attenuating the dc zoom voltage to compensate for variations of the dc component of the ramp voltage to maintain the dc component constant with changes in the vertical sweep amplitude caused by the dc zoom voltage.
Claim 8
Dependent Claim
219 words
Electronic zooming apparatus for a video camera system comprising: a solid-state target on which an image is formed, means for producing an electron beam, horizontal deflection means for producing a horizontal sweep signal for periodically shifting the electron beam to scan the target in a horizontal direction, vertical deflection means for producing a vertical sweep signal for periodically shifting the electron beam to scan said target in a vertical direction, said horizontal and vertical deflection means each comprising a sweep generator, said sweep generators both including a capacitor, a constant current source for charging said capacitor, and trigger means for periodically discharging said capacitor to a variable dc voltage level to produce a periodic ramp voltage, adjusting means for producing a dc zoom voltage and for simultaneously applying said dc zoom voltage to each of said deflection means to simultaneously control the voltage produced by each of said constant current sources over a continuous range so that the electron beam may scan rasters of different sizes, each having the same aspect ratio, and said vertical sweep generator further including a voltage divider for attenuating the dc zoom voltage to compensate for variations of the dc component of the ramp voltage to maintain the dc component constant with changes in the vertical sweep amplitude caused by the dc zoom voltage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-12-05 | 1976-06-05 | 1976-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-05 | 1980-06-05 | 1980-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-05 | 1984-06-05 | 1984-12-05 | $7700.00 | Window Closed / Lapsed |