Patent US4141033A successfully refreshed from Google Patents.
US4141033A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for automatically controlling the asymmetry of a signal
Assignee: US Philips Corp
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Filing: 1977-08-23
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Granted: 1979-02-20
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Expires: 1997-08-23
Abstract
Abstract When a color television signal is recorded on a video disc and said signal is read a complication arises owing to the asymmetry which is produced in the signal by the various process steps. This gives rise to spurious components whose influence should be minimized by a suitably selected coding system. The invention proposes a device with which the influence of this asymmetry is automatically reduced. This device comprises two separator stages for supplying two sub-signals which respectively represent the rising and falling edges of the information signal. The phase relationship between these two sub-signals is controlled with the aid of a phase shifter. The control signal required for this is produced with the aid of a detector which responds to an asymmetry component in the information signal. The two corrected sub-signals are subsequently recombined to the information signal.
Inventors
- 👤 Eeltje de Boer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:29
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/156; H03K5/1565; H04; H04N; H04N5/00; H04N5/76; H04N5/91
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
150 words
A device for controlling an asymmetrical component in an information signal which contains at least a frequency modulated carrier wave, which control circuit comprises: a first separating stage means for deriving a first sub-signal from the information signal, which first sub-signal only represents the rising edges of the information signal, a second separating stage means for deriving a second sub-signal from the information signal which second sub-signal only represents the falling edges of the information signal, a detector means for detecting the asymmetry component in the information signal and for deriving a control signal therefrom, a phase shifter means for controlling the phase relationship between the first and the second sub-signal depending on the control signal, and a recombination circuit means for recombining the first and second phase controlled sub-signals to provide a corrected information signal whose consecutive edges are sequentially defined by the first and second phase controlled sub-signals.
Claim 2
Independent Claim
150 words
A device for controlling an asymmetrical component in an information signal which contains at least a frequency modulated carrier wave, which control circuit comprises: a first separating stage means for deriving a first sub-signal from the information signal, which first sub-signal only represents the rising edges of the information signal, a second separating stage means for deriving a second sub-signal from the information signal which second sub-signal only represents the falling edges of the information signal, a detector means for detecting the asymmetry component in the information signal and for deriving a control signal therefrom, a phase shifter means for controlling the phase relationship between the first and the second sub-signal depending on the control signal, and a recombination circuit means for recombining the first and second phase controlled sub-signals to provide a corrected information signal whose consecutive edges are sequentially defined by the first and second phase controlled sub-signals.
Claim 3
Dependent Claim
69 words
A device as claimed in claimed in claim 1, wherein the first and the second separating stage means respectively comprises a first and a second frequency divider stage means for supplying the first and the second sub-signal respectively, the first sub-signal having consecutive edges corresponding to the rising edges of the information signal and the second sub-signal having consecutive edges corresponding to the falling edges of this information signal.
Claim 4
Dependent Claim
51 words
A device as claimed in claim 1, wherein the phase shifter means comprises a first delay means for delaying the first sub-signal and a second delay means for delaying the second sub-signal, at least one of said delay means having a delay time which is variable depending on the control signal.
Claim 5
Dependent Claim
21 words
A device as claimed in claim 1, wherein the detector comprises a low-pass filter to which the information signal is applied.
Claim 6
Dependent Claim
18 words
A device as claimed in claim 3, wherein the corrected information signal is applied to the detector means.
Claim 7
Dependent Claim
26 words
A device as claimed in claim 1, wherein the detector means is adapted to measure the amplitude of a spurious component produced by the asymmetry component.
Claim 8
Dependent Claim
60 words
A device as claimed in claim 5 for processing an information signal which comprises a composite color television signal which is frequency modulated on a carrier wave, wherein the detector is adapted to measure the amplitude of a spurious component which has a frequency equal to the subcarrier frequency of the chrominance signal contained in the composite color television signal.
Claim 9
Dependent Claim
33 words
A device as claimed in claim 5, wherein the detector is adapted to measure the amplitude of a spurious component with a frequency equal to twice the frequency of the modulated carrier wave.
References Cited (Backward Citations)
US3988531A
Cited
US3988532A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-02-19 | 1982-08-21 | 1983-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-19 | 1986-08-21 | 1987-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-19 | 1990-08-21 | 1991-02-20 | $7700.00 | Window Closed / Lapsed |