Patent US4539488A successfully refreshed from Google Patents.
US4539488A
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US
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Pulse wave to parabola wave converter
Assignee: Zenith Electronics LLC
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Filing: 1984-02-01
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Granted: 1985-09-03
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Expires: 2004-02-01
Abstract
Abstract An electronic image framing circuit is described for eliminating the visible effects of pincushion distortion at the edges of a television image. Toward this end, portions of video lines which extend beyond a selected straight line image boundary are blanked by a pulse processor. The pulse processor responds to conventional horizontal rate and vertical rate pulses for developing blanking pulses whose widths are varied at a vertical rate. The modified blanking pulses are applied to a conventional blanking circuit for blanking the portions of video lines which extend beyond the desired image area. A parabola generator is also described for use in developing the modified blanking pulses.
Inventors
- 👤 Stanley E. Lehnert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:39
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/22; H04N3/23; H04N3/233; H04N3/2335
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
138 words
A low insertion loss circuit for converting a pulse signal to a parabolic waveform, comprising: an input terminal for receiving the pulse signal; a first integrating resistance-capacitance network having a first input and output terminal said first input terminal coupled to said input terminal; a second integrating resistance-capacitance network having a second input and output terminal, said second input terminal coupled in series with said first output terminal; a third resistance-capacitance network having a third input and output terminal, said third input terminal coupled in series with said second output terminal for developing said parabolic waveform; and a diode coupled between said input terminal and said first output terminal assuming conductive and non-conductive states in response to opposite polarities of the pulse signal so as to alternately configure the circuit as a two-stage and a three-stage integrator, respectively.
Claim 2
Dependent Claim
138 words
A low insertion loss circuit for converting a pulse signal to a parabolic waveform, comprising: an input terminal for receiving the pulse signal; a first integrating resistance-capacitance network having a first input and output terminal said first input terminal coupled to said input terminal; a second integrating resistance-capacitance network having a second input and output terminal, said second input terminal coupled in series with said first output terminal; a third resistance-capacitance network having a third input and output terminal, said third input terminal coupled in series with said second output terminal for developing said parabolic waveform; and a diode coupled between said input terminal and said first output terminal assuming conductive and non-conductive states in response to opposite polarities of the pulse signal so as to alternately configure the circuit as a two-stage and a three-stage integrator, respectively.
Claim 3
Dependent Claim
30 words
A circuit as set forth in claim 1 wherein each resistance-capacitance network includes a resistance in series with the network's input and a capacitance coupling the network's output to ground.
Claim 4
Dependent Claim
32 words
A circuit as set forth in claim 2 wherein the values of said resistances and capacitances are selected to provide a phase shift equal to substantially 180 degrees for the pulse input.
References Cited (Backward Citations)
US2890420A
Cited
US3872449A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-02 | 1989-03-04 | 1989-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-02 | 1993-03-04 | 1993-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-02 | 1997-03-04 | 1997-09-03 | $7700.00 | Window Closed / Lapsed |