Patent US4054816A successfully refreshed from Google Patents.
US4054816A
Expired / Lapsed
US
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Sweep circuit for cathode-ray tube display
Assignee: International Business Machines Corp
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Filing: 1976-07-02
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Granted: 1977-10-18
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Expires: 1996-07-02
Abstract
Abstract A recurrent digital sweep signal starts an integrator fed by a constant current. The integrator includes push-pull Darlington stages, which act as alternately conducting controlled current sources for split deflection coils outside the integrator feedback loop. A phase shifter provides arcsine correction. A time-out circuit avoids excessive dissipation if the sweep signal should be lost.
Inventors
- 👤 Steven Dennis Keidl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:46
CPC Classifications
G; G09; G09G; G09G1/00; G09G1/04; H; H03; H03K; H03K4/00; H03K4/06; H03K4/08; H03K4/48; H03K4/60; H03K4/69; H03K4/71
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
113 words
A sweep circuit for a cathode-ray tube display, comprising: a reference for producing a constant reference signal; an integrator responsive to said reference signal and having a feedback loop for producing a drive signal with a rate of change determined by said reference signal; and driver means being responsive to said drive signal for passing a time-varying output current through a deflection-coil means, said driver means having a sensor receiving said output current and coupled to said feedback loop, said deflection coil means being connected outside said feedback loop; and trigger means coupled to said integrater and to said reference, for resetting said drive signal to a value determined by said reference signal.
Claim 2
Dependent Claim
113 words
A sweep circuit for a cathode-ray tube display, comprising: a reference for producing a constant reference signal; an integrator responsive to said reference signal and having a feedback loop for producing a drive signal with a rate of change determined by said reference signal; and driver means being responsive to said drive signal for passing a time-varying output current through a deflection-coil means, said driver means having a sensor receiving said output current and coupled to said feedback loop, said deflection coil means being connected outside said feedback loop; and trigger means coupled to said integrater and to said reference, for resetting said drive signal to a value determined by said reference signal.
Claim 3
Dependent Claim
43 words
The sweep circuit of claim 1, wherein said deflection-coil means comprises a pair of split deflection coils, and wherein said driver means comprises a pair of drivers, each of said drivers being coupled to one of said coils and to said current sensor.
Claim 4
Dependent Claim
19 words
The sweep circuit of claim 2, wherein said current sensor is a resistor coupled to both of said drivers.
Claim 5
Dependent Claim
38 words
The sweep circuit of claim 3, wherein each of said drivers includes a transistor coupled between said resistor and one end of one of said coils, another end of said one coil being coupled to a supply voltage.
Claim 6
Dependent Claim
19 words
The sweep circuit of claim 1, wherein said reference signal is a reference current flowing in a first direction.
Claim 7
Dependent Claim
44 words
The sweep circuit of claim 5, wherein said trigger means produces a variable reset current flowing oppositely to said reference current, said reset current decreasing to the value of said reference current at a predetermined voltage depending upon the value of said reference current.
Claim 8
Dependent Claim
18 words
The sweep circuit of claim 1, wherein said trigger means is responsive to a recurrent external trigger signal.
Claim 9
Dependent Claim
39 words
The sweep circuit of claim 7, wherein said trigger means includes means for producing an internal trigger signal at a rate lower than a nominal rate of said external signal, said last-named means being inhibited by said external signal.
Claim 10
Dependent Claim
20 words
The sweep circuit of claim 1, wherein said feedback loop includes a phase shifter for modifying said time-varying drive 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) | 1980-10-17 | 1981-04-18 | 1981-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-17 | 1985-04-18 | 1985-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-17 | 1989-04-18 | 1989-10-18 | $7700.00 | Window Closed / Lapsed |