US4091420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video amplifier
Assignee: Victor Company of Japan Ltd
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Filing: 1977-01-07
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Granted: 1978-05-23
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Expires: 1997-01-07
Abstract
Abstract A high frequency component detector and a limiter or clipper are provided in a video amplifier, detecting a high frequency component in an incoming video signal, responsive to the detection and clipping only the high frequency component in excess of a predetermined voltage.
Inventors
- 👤 Yasuo Omori
- 👤 Hiroshi Kataoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:38
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/205
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
120 words
A video amplifier for use in a television receiver, comprising in combination: a channel including an input terminal to which a video signal is applied and an output terminal from which the video signal is delivered; a frequency detector connected to the input terminal for detecting high frequency components of said video signal to provide a first output signal; an amplitude detector connected to the input terminal for detecting when said video signal is in excess of a predetermined voltage level to provide a second output signal; and a clamping circuit responsive to a simultaneous occurrence of said first and second output signals for clamping the amplitude of said video signal at said output terminal to said predetermined voltage level.
Claim 2
Dependent Claim
120 words
A video amplifier for use in a television receiver, comprising in combination: a channel including an input terminal to which a video signal is applied and an output terminal from which the video signal is delivered; a frequency detector connected to the input terminal for detecting high frequency components of said video signal to provide a first output signal; an amplitude detector connected to the input terminal for detecting when said video signal is in excess of a predetermined voltage level to provide a second output signal; and a clamping circuit responsive to a simultaneous occurrence of said first and second output signals for clamping the amplitude of said video signal at said output terminal to said predetermined voltage level.
Claim 3
Dependent Claim
57 words
A video amplifier a claimed in claim 1, wherein said clamping circuit comprises a source of voltage and a pair of first and second gate-controlled switching devices connected in series between said voltage source and said output terminal and responsive to said first and second output signals, respectively, to couple said voltage source to said output terminal.
Claim 4
Dependent Claim
67 words
A video amplifier as claimed in claim 2, wherein said frequency detector comprises a high pass filter for allowing the high frequency components of the video signal to pass therethrough and means connected to the high pass filter for generating a pulse in response to the high frequency components passing through said high pass filter, and wherein said first gate-controlled switching device is responsive to said pulse.
Claim 5
Dependent Claim
16 words
A video amplifier as claimed in claim 3, wherein said pulse generating means includes an amplifier.
Claim 6
Dependent Claim
75 words
A video amplifier as claimed in claim 1, wherein said clamping circuit comprises a source of voltage and a gate-controlled switching device responsive to said first output signal, and wherein said amplitude detector comprises a diode connected in series with said switching device between said voltage source and said output terminal and poled such that said voltage is coupled to said output terminal when said video signal falls below the magnitude of said voltage source.
Claim 7
Dependent Claim
67 words
A video amplifier as claimed in claim 5, wherein said frequency detector comprises a high pass filter for allowing the high frequency components of the video signal to pass therethrough and means connected to the high pass filter for generating a pulse in response to the high frequency components passing through said high pass filter, and wherein said gate-controlled switching device is responsive to said generated pulse.
Claim 8
Dependent Claim
16 words
A video amplifier as claimed in claim 6, wherein said pulse generating means includes an amplifier.
Claim 9
Dependent Claim
16 words
A video amplifier as claimed in claim 1, wherein the amplitude detector is a Schmitt trigger.
References Cited (Backward Citations)
US3288930A
Cited
US3472954A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |