Patent US4647960A successfully refreshed from Google Patents.
US4647960A
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Vertical contour emphasis de-emphasis circuit
Assignee: Hitachi Ltd
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Filing: 1985-09-18
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Granted: 1987-03-03
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Expires: 2005-09-18
Abstract
Abstract Disclosed is a circuit for emphasizing a video signal in the vertical direction of a television picture for minimizing noise appearing during reproduction. In the circuit, a signal obtained by delaying an input video signal by one horizontal scanning period is positively fed back through a feedback circuit to the input of the input video signal. An amplitude difference signal between the video signal after being fed back through a positive feedback loop and the delayed video signal is produced and added to the input video signal to provide an output video signal.
Inventors
- 👤 Kuniaki Miura
- 👤 Yasufumi Yunde
- 👤 Kazunori Kotani
- 👤 Isao Fukushima
- 👤 Kenji Kano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:40
CPC Classifications
H; H03; H03G; H03G7/00; H04; H04N; H04N5/00; H04N5/14; H04N5/142; H04N5/76; H04N5/91; H04N5/92; H04N5/923; H04N9/00; H04N9/64; H04N9/646
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
127 words
An emphasis circuit emphasizing a video signal in the vertical direction of a television picture, comprising: a first arithmetic circuit adding a feedback signal to an input video signal; a delay circuit delaying the output of said first arithmetic circuit by a predetermined delay time to generate a delayed output which provides said feedback signal; a second arithmetic circuit producing a signal indicative of the amplitude difference between the output of said first arithmetic circuit and that of said delay circuit; a linear amplifier circuit adjusting the magnitude of said amplitude difference signal applied from said second arithmetic circuit to a predetermined level; and a third arithmetic circuit producing an output video signal by adding the output of said linear amplifier circuit to said input video signal.
Claim 2
Dependent Claim
127 words
An emphasis circuit emphasizing a video signal in the vertical direction of a television picture, comprising: a first arithmetic circuit adding a feedback signal to an input video signal; a delay circuit delaying the output of said first arithmetic circuit by a predetermined delay time to generate a delayed output which provides said feedback signal; a second arithmetic circuit producing a signal indicative of the amplitude difference between the output of said first arithmetic circuit and that of said delay circuit; a linear amplifier circuit adjusting the magnitude of said amplitude difference signal applied from said second arithmetic circuit to a predetermined level; and a third arithmetic circuit producing an output video signal by adding the output of said linear amplifier circuit to said input video signal.
Claim 3
Dependent Claim
36 words
An emphasis circuit as claimed in claim 1, further comprising a non-linear circuit interposed between said second and third arithmetic circuits for limiting the amount of emphasis depending on the output of said second arithmetic circuit.
Claim 4
Dependent Claim
30 words
An emphasis circuit as claimed in claim 1, wherein said input video signal is a luminance signal, and the delay time of said delay circuit is one horizontal scanning period.
Claim 5
Dependent Claim
34 words
An emphasis circuit as claimed in claim 1, wherein said input video signal is a chrominance signal, and said feedback signal is provided by inverting the phase of the output of said delay circuit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-02 | 1990-09-01 | 1991-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-02 | 1994-09-01 | 1995-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-02 | 1998-09-01 | 1999-03-03 | $7700.00 | Window Closed / Lapsed |