Patent US3681518A successfully refreshed from Google Patents.
US3681518A
Expired / Lapsed
US
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Color video signal correction system
Assignee: Victor Company of Japan Ltd
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Filing: 1970-05-08
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Granted: 1972-08-01
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Expires: 1990-05-08
Abstract
Abstract A color video signal correction system for a video tape recorder removes stably differential frequency changes and differential phase shifts. The system comprises a trigger oscillator which oscillates in phase with a burst signal taken out of the chrominance signal. A phase comparator circuit means compares a phase of a horizontal synchronizing signal separated from a luminance signal, by a horizontal synchronizing separation circuit means, with a phase of a horizontal synchronizing signal delayed in one horizontal line scanning time from the separated horizontal synchronizing signal. The trigger oscillator is controlled by an output of the phase comparator.
Inventors
- 👤 Tsuneyoshi Hidaka
- 👤 Akiyoshi Morita
- 👤 Yoshihiko Honjo
- 👤 Takashi Nishimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:50
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N9/898
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
274 words
A color video signal correction system comprising first filter means for filtering out a chrominance signal from a color video signal, first frequency converter means responsive to a first predetermined frequency for changing the frequency of the chrominance signal supplied by said first filter means, gating means for taking out a burst signal from said chrominance signal, trigger oscillator circuit means actuated by said burst signal, means for controlling the oscillation of said trigger oscillator comprising second frequency converter means operated responsive to a second predetermined frequency for changing the frequency of the output of said trigger oscillator, third frequency converter means for mixing the outputs of said first and second frequency converter means to produce a chrominance signal with a frequency differential removed therefrom, second filter means for filtering out a luminance signal from a color video signal, means for mixing said luminance signal and said chrominance signal produced by said third frequency converter means, said means for controlling the oscillation of said trigger oscillator further including an open loop control circuit comprising means for separating a horizontal synchronizing signal from the luminance signal supplied by said second filter means, means for delaying the horizontal synchronizing signal supplied by said separation means for a delay time period equal to one horizontal line scanning time, means for comparing the phase of the horizontal synchronizing signal supplied by said separating means with the phase of the delayed signal supplied by said delay means, and said triGger oscillator being controlled in its natural resonance frequency to follow up the frequency changes of said burst signal responsive to a detected differential output of said phase comparing means.
Claim 2
Dependent Claim
274 words
A color video signal correction system comprising first filter means for filtering out a chrominance signal from a color video signal, first frequency converter means responsive to a first predetermined frequency for changing the frequency of the chrominance signal supplied by said first filter means, gating means for taking out a burst signal from said chrominance signal, trigger oscillator circuit means actuated by said burst signal, means for controlling the oscillation of said trigger oscillator comprising second frequency converter means operated responsive to a second predetermined frequency for changing the frequency of the output of said trigger oscillator, third frequency converter means for mixing the outputs of said first and second frequency converter means to produce a chrominance signal with a frequency differential removed therefrom, second filter means for filtering out a luminance signal from a color video signal, means for mixing said luminance signal and said chrominance signal produced by said third frequency converter means, said means for controlling the oscillation of said trigger oscillator further including an open loop control circuit comprising means for separating a horizontal synchronizing signal from the luminance signal supplied by said second filter means, means for delaying the horizontal synchronizing signal supplied by said separation means for a delay time period equal to one horizontal line scanning time, means for comparing the phase of the horizontal synchronizing signal supplied by said separating means with the phase of the delayed signal supplied by said delay means, and said triGger oscillator being controlled in its natural resonance frequency to follow up the frequency changes of said burst signal responsive to a detected differential output of said phase comparing means.
Claim 3
Dependent Claim
120 words
The system of claim 1 in which said means for controlling the oscillation of said trigger oscillator comprises means for separating a horizontal synchronizing signal from the luminance signal supplied by said second filter means, means for delaying the horizontal synchronizing signal supplied by said separation means in one horizontal line scanning time, means for generating a gate pulse from the output of said delay means, means for forming an inclined waveform signal of a phase-voltage conversion from the horizontal synchronizing signal supplied by said separation means, and means for comparing the phase of the gate pulse supplied by said gate pulse generating means with the phase of the inclined waveform signal supplied by said inclined waveform signal forming means.
Claim 4
Dependent Claim
204 words
The system of claim 1 in which said means for controlling the oscillation of said trigger oscillator comprises means for separating a horizontal synchronizing signal from the luminance signal supplied by said second filter means, means for frequency modulating the synchronizing signal from said separation means, means for delaying the output of said frequency modulating means in one horizontal line scanning time, means for demodulating the output of said delay means, multivibrator circuit means driven by the output of said demodulating means, means for generating a gate pulse by the output of said multivibrator, means for forming an inclined waveform signal of a phase-voltage conversion from the synchronizing signal of a phase-voltage conversion from the synchronizing signal supplied by said separation means, means for comparing the phase of the gate pulse supplied by said gate pulse generating means with the phase of the inclined waveform supplied by said inclined waveform forming means, circuit means for holding the output of said phase comparing means in one horizontal line scanning time, and means comprising a variable capacitor for converting the output of said holding circuit means into an electrostatic charge, said trigger oscillator having a tank circuit controlled by the capacity variations of said variable capacitor.
Claim 5
Dependent Claim
102 words
The system of claim 1 further having a closed loop control circuit comprising circuit means responsive to the horizontal synchronizing signal supplied by said horizontal synchronizing separation circuit for gating the oscillation output of said trigger oscillator, ringing oscillator circuit means driven by the gated output signal of said gate circuit means, and phase comparator circuit means for comparing the phase of the oscillation output of said ringing oscillator with the phase of the burst signal taken out of said chrominance signal, said trigger oscillator being further controlled by the output of said phase comparator means of said closed loop control circuit.
Claim 6
Dependent Claim
102 words
The system of claim 3 further having a closed loop control circuit comprising circuit means responsive to the horizontal synchronizing signal supplied by said horizontal synchronizing separation circuit for gating the oscillation output of said trigger oscillator, ringing oscillator circuit means driven by the gated output signal of said gate circuit means, and phase comparator circuit means for comparing the phase of the oscillation output of said ringing oscillator with the phase of the burst signal taken out of said chrominance signal, said trigger oscillator being further controlled by the output of said phase comparator means of said closed loop control circuit.
Claim 7
Dependent Claim
159 words
The system of claim 1 further having a closed loop control circuit comprising circuit means responsive to the horizontal synchronizing signal supplied by said horizontal synchronizing separation circuit for gating the oscillation output of said trigger oscillator, ringing oscillator circuit means driven by the gated output signal of saId gate circuit means, phase comparator circuit means for comparing the phase of the oscillation output of said ringing oscillator with the phase of the burst signal taken out of said chrominance signal, means for gating the output of said phase comparator means by the horizontal synchronizing signal supplied by the horizontal synchronizing separation circuit, holding circuit means for holding the output of said gating means in one horizontal line scanning time, and means comprising a variable capacitor coupled to said holding means for converting a signal from said phase comparator into an electrostatic charge, said trigger oscillator having a tank circuit controlled by the capacity variations of said variable capacitor.
Claim 8
Dependent Claim
156 words
The system of claim 3 further having a closed loop control circuit comprising circuit means responsive to the horizontal synchronizing signal supplied by said horizontal synchronizing separation circuit for gating the oscillation output of said trigger oscillator, ringing oscillator circuit means driven by the gated output signal of said gate circuit means, phase comparator circuit means for comparing the phase of the oscillation output of said ringing oscillator with the phase of the burst signal taken out of said chrominance signal, means responsive to the horizontal synchronizing signal supplied by the horizontal synchronizing separation circuit for gating the output of said phase comparator means, holding circuit means for holding the output of said gating means in one horizontal line scanning time, and means comprising a variable capacitor for converting the output of the phase comparator circuit into an electrostatic charge, said trigger oscillator having a tank circuit controlled by the capacity variations of said variable capacitor.
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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) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |