US3674920A
Expired / Lapsed
US
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Time base correction system for video recording apparatus
Assignee: Data Memory Inc
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Filing: 1970-09-14
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Granted: 1972-07-04
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Expires: 1990-09-14
Abstract
Abstract A color correction system wherein a comb filter circuit and a heterdyne circuit are operatively interrelated to provide time base correction with de minimis reduction in luminance information. The comb filter portion of the circuit provides for the extraction and separation of chrominance and luminance information while the heterodyne portion provides time base correction of the unstable chrominance information. After stabilization, the chrominance signal is recombined with the luminance signal to reconstitute the composite video output signal.
Inventors
- 👤 Yves C Faroudja
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:36
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N9/898
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
187 words
An electronic time base correction system for use with video recording apparatus comprising: filter means including, a comb filter for receiving and separating out the luminance and chrominance information from an input composite video signal to provide an unstable chrominance signal and a luminance signal, said comb filter including, a chrominance bandpass filter, a 63.36 microsecond signal delay means, a chrominance adder for developing said unstable chrominance signal having a first input terminal coupled to the output of said chrominance bandpass filter through said 63.36 microsecond delay means and a second input terminal coupled directly to the output terminal of said chrominance bandpass filter, an adjustable delay means, and a luminance adder for developing said luminance signal having one input terminal coupled to the output terminal of said chrominance adder and another input terminal for receiving said input composite video signal after it is delayed by said adjustable delay means; heterodyning means responsive to said unstable chrominance signal for developing a stabilized chrominance signal; and signal adder means responsive to said stabilized chrominance signal and said luminance signal for developing a time base stabilized composite video signal.
Claim 2
Dependent Claim
187 words
An electronic time base correction system for use with video recording apparatus comprising: filter means including, a comb filter for receiving and separating out the luminance and chrominance information from an input composite video signal to provide an unstable chrominance signal and a luminance signal, said comb filter including, a chrominance bandpass filter, a 63.36 microsecond signal delay means, a chrominance adder for developing said unstable chrominance signal having a first input terminal coupled to the output of said chrominance bandpass filter through said 63.36 microsecond delay means and a second input terminal coupled directly to the output terminal of said chrominance bandpass filter, an adjustable delay means, and a luminance adder for developing said luminance signal having one input terminal coupled to the output terminal of said chrominance adder and another input terminal for receiving said input composite video signal after it is delayed by said adjustable delay means; heterodyning means responsive to said unstable chrominance signal for developing a stabilized chrominance signal; and signal adder means responsive to said stabilized chrominance signal and said luminance signal for developing a time base stabilized composite video signal.
Claim 3
Dependent Claim
37 words
An electronic time base correction system as recited in claim 1 and further including an active notch filter coupling said luminance adder to said signal adder means for removing any vestigal chrominance components from said luminance signal.
Claim 4
Dependent Claim
42 words
An electronic time base correction system as recited in claim 2 and further including a 1 microsecond signal delay means coupling said notch filter to said signal adder means for delaying said luminance signal prior to addition with said stabilized chrominance signal.
Claim 5
Dependent Claim
120 words
An electronic time base correction system for use with video recording apparatus comprising: filter means for receiving and separating out the luminance and chrominance information from an input composite video signal to provide an unstable chrominance signal and a luminance signal; heterodyning means responsive to said unstable chrominance signal for developing a stabilized chrominance signal, said heterodyning means including a voltage controlled oscillator for developing an unstable subcarrier signal which is phase-locked with said unstable chrominance signal, and modulator means responsive to said unstable subcarrier signal and said unstable chrominance signal for developing said stabilized chrominance signal; and signal adder means responsive to said stabilized chrominance signal and said luminance signal for developing a time base Stabilized composite video signal.
Claim 6
Dependent Claim
120 words
An electronic time base correction system for use with video recording apparatus comprising: filter means for receiving and separating out the luminance and chrominance information from an input composite video signal to provide an unstable chrominance signal and a luminance signal; heterodyning means responsive to said unstable chrominance signal for developing a stabilized chrominance signal, said heterodyning means including a voltage controlled oscillator for developing an unstable subcarrier signal which is phase-locked with said unstable chrominance signal, and modulator means responsive to said unstable subcarrier signal and said unstable chrominance signal for developing said stabilized chrominance signal; and signal adder means responsive to said stabilized chrominance signal and said luminance signal for developing a time base Stabilized composite video signal.
Claim 7
Dependent Claim
120 words
An electronic time base correction system as recited in claim 4 wherein said modulator means includes a local oscillator for developing a stable reference signal, a first ring modulator means responsive to said unstable subcarrier signal and said stable reference signal for developing an unstable sum output signal, a second ring modulator means responsive to said unstable chrominance signal and said unstable sum output signal for developing a stable difference output signal, a third ring modulator means responsive to a stable subcarrier signal and said stable reference signal for developing a stable sum output signal, and a fourth ring modulator means responsive to said stable difference output signal and said stable sum output signal for developing said stabilized chrominance signal.
Claim 8
Dependent Claim
55 words
An electronic time base correction system as recited in claim 1 wherein said heterodyning means includes a voltage controlled oscillator for developing an unstable subcarrier signal which is phase locked with said unstable chrominance signal, and modulator means responsive to said unstable subcarrier signal and said unstable chrominance signal for developing said stabilized chrominance signal.
Claim 9
Dependent Claim
120 words
An electronic time base correction system as recited in claim 6 wherein said modulator means includes a local oscillator for developing a stable reference signal, a first ring modulator means responsive to said unstable subcarrier signal and said stable reference signal for developing an unstable sum output signal, a second ring modulator means responsive to said unstable chrominance signal and said unstable sum output signal for developing a stable difference output signal, a third ring modulator means responsive to a stable subcarrier signal and said stable reference signal for developing a stable sum output signal, and a fourth ring modulator means responsive to said stable difference output signal and said stable sum output signal for developing said stabilized chrominance signal.
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) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |