Patent US3825796A successfully refreshed from Google Patents.
US3825796A
Expired / Lapsed
US
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Crt geometry correction network
Assignee: RTX Corp
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Filing: 1973-01-26
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Granted: 1974-07-23
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Expires: 1993-01-26
Abstract
Abstract Geometry distortion, caused by the radius of curvature of the face of a CRT being larger than the axial distance of the CRT beam source to the CRT face, is corrected by a network which is an implementation of the precise mathematical relationships which describe the correction of the geometry distortion. A nonlinear network is used to generate correction signals which are subtracted from the uncorrected deflection signals, thereby providing corrected deflection signals.
Inventors
- 👤 V Bello
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:04
CPC Classifications
G; G01; G01R; G01R13/00; G01R13/20; G01R13/22; H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/22; H04N3/23; H04N3/233; H04N3/2335
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
244 words
A cathode ray tube magnetic deflection circuitry for providing, to a cathode ray tube, deflection signals corrected for geometry distortion in response to uncorrected horizontal and vertical deflection signals, comprising: means providing a signal proportional to the sum of the weighted squares of said uncorrected deflection signals; a nonlinear, biased diode-resistor breakpoint network responsive to said sum of the weighted squares signal, wherein the bias and resistor values are selected to provide breakpoints of said nonlinear network so that it is responsive to said sum of the weighted squares, z, to provide a common correction signal g (z) substantially in accordance with The relationship, g(z) 1 square root 2n2 - 2n + 1 - 2(n - 1) square root n2 z where n the ratio of the radius of curvature to the radius of deflection of the cathode ray tube, and z said sum of the weighted squares of said uncorrected deflection signals; means for providing a horizontal correction signal proportional to the product of said uncorrected horizontal deflection signal and said common correction signal, and for providing a vertical correction signal proportional to the product of said uncorrected vertical deflection signal and said common correction signal; and means for providing a corrected horizontal deflection signal proportional to the difference of said uncorrected horizontal deflection signal and said horizontal correction signal, and for providing a corrected vertical deflection signal proportional to the difference of said uncorrected vertical deflection signal and said vertical correction signal.
Claim 2
Dependent Claim
244 words
A cathode ray tube magnetic deflection circuitry for providing, to a cathode ray tube, deflection signals corrected for geometry distortion in response to uncorrected horizontal and vertical deflection signals, comprising: means providing a signal proportional to the sum of the weighted squares of said uncorrected deflection signals; a nonlinear, biased diode-resistor breakpoint network responsive to said sum of the weighted squares signal, wherein the bias and resistor values are selected to provide breakpoints of said nonlinear network so that it is responsive to said sum of the weighted squares, z, to provide a common correction signal g (z) substantially in accordance with The relationship, g(z) 1 square root 2n2 - 2n + 1 - 2(n - 1) square root n2 z where n the ratio of the radius of curvature to the radius of deflection of the cathode ray tube, and z said sum of the weighted squares of said uncorrected deflection signals; means for providing a horizontal correction signal proportional to the product of said uncorrected horizontal deflection signal and said common correction signal, and for providing a vertical correction signal proportional to the product of said uncorrected vertical deflection signal and said common correction signal; and means for providing a corrected horizontal deflection signal proportional to the difference of said uncorrected horizontal deflection signal and said horizontal correction signal, and for providing a corrected vertical deflection signal proportional to the difference of said uncorrected vertical deflection signal and said vertical correction signal.
References Cited (Backward Citations)
US3422306A
Cited
US3517252A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |