US3850412A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency and phase acquisition in a color subcarrier regenerator
Assignee: Tektronix Inc
•
Filing: 1974-02-25
•
Granted: 1974-11-26
•
Expires: 1994-02-25
Abstract
Abstract In a cathode-ray vectorscope for a PAL television system, a method and means is provided for substantially locking a vector display to the 135* and 225* references when no color burst is present. A front-panel potentiometer furnishes a variable voltage to a voltage-variable capacitance to tune the color subcarrier regenerator oscillator to the subcarrier frequency. A second front-panel potentiometer provides a fine-tuning adjustment, and by quickly manipulating the knob of this potentiometer, a momentary power surge is developed by an associated differentiating network and applied to the voltage-variable capacitance to change the phase of the regenerator subcarrier signal.
Inventors
- 👤 R Olson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:11
CPC Classifications
H; H04; H04N; H04N17/00; H04N17/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
113 words
A system for acquiring the frequency and phase of the subcarrier signal generated by a subcarrier regenerator circuit in a TV vectorscope, comprising: means for receiving an external composite video signal, said external composite video signal including a burst reference portion; means for generating a sine-wave signal at or near the subcarrier frequency, said means including a tunable oscillator; means for comparing said sine-wave signal to said burst portion and producing a first control voltage proportional to the difference therebetween; means for manually producing a second control voltage; and means for selectively receiving said first control voltage and said second control volage to provide thereoutof a correction voltage for tuning said tunable oscillator.
Claim 2
Independent Claim
113 words
A system for acquiring the frequency and phase of the subcarrier signal generated by a subcarrier regenerator circuit in a TV vectorscope, comprising: means for receiving an external composite video signal, said external composite video signal including a burst reference portion; means for generating a sine-wave signal at or near the subcarrier frequency, said means including a tunable oscillator; means for comparing said sine-wave signal to said burst portion and producing a first control voltage proportional to the difference therebetween; means for manually producing a second control voltage; and means for selectively receiving said first control voltage and said second control volage to provide thereoutof a correction voltage for tuning said tunable oscillator.
Claim 3
Dependent Claim
26 words
The system according to claim 1 wherein said means for generating a sine-wave signal including a tunable oscillator includes a crystal operable at a predetermined frequency.
Claim 4
Dependent Claim
48 words
The system according to claim 1 wherein said means for producing said first control voltage defines an automatic error voltage generator for receiving said external composite video signal and said generated sine-wave signal and developing said first control voltage in response to the frequency and phase difference therebetween.
Claim 5
Dependent Claim
31 words
The system according to claim 1 wherein said means for producing said second control voltage includes a main potentiometer and a vernier potentiometer which form a portion of a voltage-divider network.
Claim 6
Dependent Claim
36 words
The system according to claim 4 wherein said voltage divider network also includes linear voltage producing elements for providing a linear control voltage and momentary surge voltage producing elements for providing a momentary surge control voltage.
Claim 7
Dependent Claim
22 words
The system according to claim 5 wherein said momentary surge producing elements define said vernier potentiometer and a serially-connected resistor and capacitor.
Claim 8
Dependent Claim
31 words
The system according to claim 1 wherein said means for selectively receiving said first control voltage and said second control voltage includes a diode which functions as a voltage variable capacitor.
Claim 9
Independent Claim
132 words
A system for acquiring the frequency and phase of a subcarrier signal generated by a subcarrier regenerator circuit in the absence of successive color burst portions of an externally applied composite video signal, comprising: a tunable oscillator for generating a sine-wave signal at substantially the color subcarrier frequency; an error-voltage generator for comparing the frequency and phase of said sine-wave signal to the frequency and phase of said color burst portions of said composite video signal and producing an error voltage which is proportional to the difference therebetween; passive network means for producing a variable D.C. control voltage; and tuning means for selectively receiving said error voltage and said variable control voltage and producing therefrom a correction voltage to tune said tunable oscillator to the frequency and phase of the subcarrier signal.
Claim 10
Independent Claim
132 words
A system for acquiring the frequency and phase of a subcarrier signal generated by a subcarrier regenerator circuit in the absence of successive color burst portions of an externally applied composite video signal, comprising: a tunable oscillator for generating a sine-wave signal at substantially the color subcarrier frequency; an error-voltage generator for comparing the frequency and phase of said sine-wave signal to the frequency and phase of said color burst portions of said composite video signal and producing an error voltage which is proportional to the difference therebetween; passive network means for producing a variable D.C. control voltage; and tuning means for selectively receiving said error voltage and said variable control voltage and producing therefrom a correction voltage to tune said tunable oscillator to the frequency and phase of the subcarrier signal.
Claim 11
Dependent Claim
56 words
The system according to claim 8 wherein said passive network means includes a main potentiometer and a vernier potentiometer for linearly producing said variable control voltage, said passive network means also including a serially-connected resistor and capacitor for producing a momentary surge in said variable control voltage, and said tuning means includes a voltage variable capacitor.
References Cited (Backward Citations)
US2751424A
Cited
US3268657A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |