US3757034A
Expired / Lapsed
US
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Color video signal recording and reproducing system
Assignee: Victor Company of Japan Ltd
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Filing: 1972-01-12
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Granted: 1973-09-04
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Expires: 1992-01-12
Abstract
Abstract In a color video signal recording and reproducing system, a color video signal is separated into a luminance signal and a carrier chrominance signal. The luminance signal is frequency modulated, while the carrier chrominance signal is frequency converted to a lower frequency band. The frequency modulated luminance signal and the frequency converted carrier chrominance signal are superimposed one upon the other, and the superimposed signal is recorded on and reproduced from a magnetic medium. The frequency modulated luminance signal is separated from the reproduced signal and then demodulated. The frequency converted carrier chrominance signal is also separated from the reproduced signal and then reconverted to its original frequency band. A feedback loop, including a voltage control oscillator, extends from the output of the frequency converter means for reconverting the carrier chrominance signal and terminates at the second frequency converter means. The central oscillation frequency of the voltage control oscillator is sufficiently low so that the feedback loop is not substantially unlocked by frequency drifting caused by ordinary changes in ambient temperature.
Inventors
- 👤 M Fujita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:42
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/82; H04N9/83
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
365 words
A color video signal recording and reproducing system comprising first filtering means for separating a luminance signal from a color video signal, means for frequency modulating said separated luminance signal, second filtering means for separating a carrier chrominance signal from said color video signal, means comprising a source of reference signals, first frequency converting means for converting the separated frequency band of said carrier chrominance signal to a lower frequency band responsive to a reference signal, means for mixing the output from said frequency modulating means and the output from said first frequency converting means, means for recording and thereafter reproducing the mixed signal on a magnetic medium, third filtering means for separating the frequency modulated luminance signal from a signal reproduced by said reproducing means, means for demodulating the separated luminance signal, fourth filtering means for separating the frequency converted carrier chrominance signal from said signal reproduced by said reproducing means, second frequency converting means for frequency converting and restoring the separated frequency band of the carrier chrominance signal to the original frequency band, means for separating a color burst signal from the output signal of said second frequency converting means, oscillating means for producing a reference subcarrier frequency signal, means for comparing the phase of said color burst signal with the phase of the output signal of said oscillating means, means including a voltage controlled oscillator having a center oscillation frequency controlled responsive to the output from said phase comparing means, third frequency converting means for converting the output frequency of said voltage controlled oscillator into a frequency applied to said second frequency converting means, means for providing a reproduced color video signal by mixing the output from said demodulating means and the output from said second frequency converting means, wherein a feedback loop terminating at said second frequency converting means is formed by said second frequency converting means, said color burst signal separating means, said phase comparing means, said voltage controlled oscillator, and said third frequency converting means, and means for setting the center frequency of oscillation of said voltage controlled oscillator at a sufficiently low level for locking said feedback loop despite frequency drifting caused by ordinary changes in ambient temperature.
Claim 2
Dependent Claim
365 words
A color video signal recording and reproducing system comprising first filtering means for separating a luminance signal from a color video signal, means for frequency modulating said separated luminance signal, second filtering means for separating a carrier chrominance signal from said color video signal, means comprising a source of reference signals, first frequency converting means for converting the separated frequency band of said carrier chrominance signal to a lower frequency band responsive to a reference signal, means for mixing the output from said frequency modulating means and the output from said first frequency converting means, means for recording and thereafter reproducing the mixed signal on a magnetic medium, third filtering means for separating the frequency modulated luminance signal from a signal reproduced by said reproducing means, means for demodulating the separated luminance signal, fourth filtering means for separating the frequency converted carrier chrominance signal from said signal reproduced by said reproducing means, second frequency converting means for frequency converting and restoring the separated frequency band of the carrier chrominance signal to the original frequency band, means for separating a color burst signal from the output signal of said second frequency converting means, oscillating means for producing a reference subcarrier frequency signal, means for comparing the phase of said color burst signal with the phase of the output signal of said oscillating means, means including a voltage controlled oscillator having a center oscillation frequency controlled responsive to the output from said phase comparing means, third frequency converting means for converting the output frequency of said voltage controlled oscillator into a frequency applied to said second frequency converting means, means for providing a reproduced color video signal by mixing the output from said demodulating means and the output from said second frequency converting means, wherein a feedback loop terminating at said second frequency converting means is formed by said second frequency converting means, said color burst signal separating means, said phase comparing means, said voltage controlled oscillator, and said third frequency converting means, and means for setting the center frequency of oscillation of said voltage controlled oscillator at a sufficiently low level for locking said feedback loop despite frequency drifting caused by ordinary changes in ambient temperature.
Claim 3
Dependent Claim
82 words
The color video signal recording and reproducing system as defined in claim 1, in which said third frequency converting means includes a frequency converter coupled to the output of said voltage controlled oscillator and to the output of said oscillating means, said frequency converter converting the low to output center frequency of oscillation of said voltage control oscillator to a higher frequency which is applied t said second frequency converting means by means of the reference Subcarrier signal from said oscillating means.
Claim 4
Dependent Claim
68 words
The color video signal recording and reproducing system as defined in claim 1, in which said first frequency converting means converts the frequency of said carrier chrominance signal into a frequency band which is lower than the frequency band of said frequency modulated luminance signal, and the center frequency of oscillation of said voltage controlled oscillator being substantially the subcarrier frequency of said frequency converted carrier chrominance signal.
Claim 5
Dependent Claim
114 words
The color video signal recording and reproducing system as defined in claim 1, which further comprises means for separating a horizontal synchronizing signal from the luminance signal produced by said demodulating means, means for multiplying the frequency of said horizontal synchronizing signal separated by said separating means, and means whereby said third frequency converting means is supplied with the output from said voltage controlled oscillator and with the output from said frequency multiplying means to convert the low level output center frequency of oscillation to a higher frequency which is applied to said second frequency converting means by means of the multiplied frequency of said horizontal synchronizing signal supplied from said frequency multiplying means.
Claim 6
Dependent Claim
121 words
The color video signal recording and reproducing system as defined in claim 4, in which said third frequency converting means includes a first frequency converter coupled to the output of said voltage controlled oscillator operated responsive to the same reference signal that is used in said first frequency converting means, said third frequency converting means converting the low level output center frequency of oscillation into a higher frequency responsive to said reference signal, and second frequency converter means coupled to the output of said first frequency converter and operated responsive to the output of said frequency multiplying means to convert the frequency of the output signal of said first frequency converter into a frequency applied to said second frequency converting means.
Claim 7
Dependent Claim
109 words
The color video signal recording and reproducing system as defined in claim 4, in which said third frequency converting means includes a first frequency converter coupled to the output of said frequency multiplying means and operated responsive to the output from said oscillating means to convert the multiplied output frequency of said multiplying means into a higher frequency, and second frequency converter means coupled to the output of said voltage controlled oscillator and operated responsive to the output of said first frequency converter to convert the low level output center frequency of oscillation of said voltage controlled oscillator into a higher frequency applied to said second frequency converting means.
Claim 8
Dependent Claim
75 words
The color video signal recording and reproducing system as defined in claim 6, in which said first frequency converting means is adapted to convert the frequency of said carrier chrominance signal into a frequency band which is lower than the frequency band of said frequency modulated luminance signal, and said frequency multiplying means multiplying the frequency of said horizontal synchronizing signal to approximately one half the subcarrier frequency of said frequency converted carrier chrominance signal.
Claim 9
Dependent Claim
209 words
A color video signal recording and reproducing system comprising first separating means for separating luminance signals and carrier chrominance signals from video signals, first converter means for frequency converting the carrier chrominance signals to a lower frequency band, means for superimposing the luminance signals and the frequency converted chrominance signals, means for recording and reproducing the superimposed signals, second separating means for separating luminance signals and the frequency converted chrominance signals from the superimposed signals, reconverting means for reconverting the frequency converted chrominance signals to the original frequency band of the carrier chrominance signals, a feedback loop extending from the output of said reconverting means and terminating at said reconverting means, said feedback loop including a voltage controlled oscillator having a center oscillation frequency which is controlled responsive to a voltage corresponding to phase shifts of the color burst signals included in said carrier chrominance signals, wherein the center oscillation frequency of the voltage controlled oscillator is held at a low level which maintains the feedback loop in a substantially locked condition despite any frequency drift caused by changes in ambient temperature, and means for providing reproduced color video signals by mixing the luminance signals from said second separating means and the carrier chrominance signals from said reconverting means.
Claim 10
Dependent Claim
209 words
A color video signal recording and reproducing system comprising first separating means for separating luminance signals and carrier chrominance signals from video signals, first converter means for frequency converting the carrier chrominance signals to a lower frequency band, means for superimposing the luminance signals and the frequency converted chrominance signals, means for recording and reproducing the superimposed signals, second separating means for separating luminance signals and the frequency converted chrominance signals from the superimposed signals, reconverting means for reconverting the frequency converted chrominance signals to the original frequency band of the carrier chrominance signals, a feedback loop extending from the output of said reconverting means and terminating at said reconverting means, said feedback loop including a voltage controlled oscillator having a center oscillation frequency which is controlled responsive to a voltage corresponding to phase shifts of the color burst signals included in said carrier chrominance signals, wherein the center oscillation frequency of the voltage controlled oscillator is held at a low level which maintains the feedback loop in a substantially locked condition despite any frequency drift caused by changes in ambient temperature, and means for providing reproduced color video signals by mixing the luminance signals from said second separating means and the carrier chrominance signals from said reconverting means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |