US3609220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vertical scan circuit
Assignee: Thomas International Corp
•
Filing: 1969-06-03
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Granted: 1971-09-28
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Expires: 1989-06-03
Abstract
Abstract A vertical scan circuit for a television receiver in which a free-running oscillator is synchronized by the vertical synchronizing component of the received signal. The free-running frequency of the vertical oscillator is varied in accordance with the amplitude of the received television signal.
Inventors
- 👤 Lawrence R Poel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:03
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/04; H04N5/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
76 words
In a receiver for a television signal having periodic scansynchronizing information and subject to variations in amplitude, a scan-generating circuit, comprising: an oscillator having a free-running frequency which differs from the frequency of said scan-synchronizing information; means for applying said scan-synchronizing information to said oscillator to modify the oscillator frequency in accordance with the frequency of the synchronizing information; and means responsive to amplitude of the received signal for varying the free-running frequency of said oscillator.
Claim 2
Dependent Claim
76 words
In a receiver for a television signal having periodic scansynchronizing information and subject to variations in amplitude, a scan-generating circuit, comprising: an oscillator having a free-running frequency which differs from the frequency of said scan-synchronizing information; means for applying said scan-synchronizing information to said oscillator to modify the oscillator frequency in accordance with the frequency of the synchronizing information; and means responsive to amplitude of the received signal for varying the free-running frequency of said oscillator.
Claim 3
Dependent Claim
67 words
The scan generating circuit of claim 1 in which said oscillator includes a circuit device which changes condition in accordance with a control potential, a circuit for developing a time varying control potential for said circuit device, means for adding said scan-synchronizing information to said time varying control potential and means for modifying the time varying control potential in accordance with the amplitude of said received signal.
Claim 4
Dependent Claim
14 words
The scan-generating circuit of claim 2 in which said oscillator is a relaxation oscillator.
Claim 5
Dependent Claim
65 words
The scan-generating circuit of claim 3 in which said relaxation oscillator is a multivibrator having one portion which conducts while the other portion is cut off during the scan period, said other portion having a control element to which said time varying control potential is applied, and means for varying a bias on said control element in accordance with the amplitude of said received signal.
Claim 6
Dependent Claim
31 words
The scan-generating circuit of claim 4 in which said receiver includes an automatic gain control circuit and the bias on said control element is established in accordance with the output thereof.
Claim 7
Dependent Claim
29 words
The scan-generating circuit of claim 4 including means for varying the potential on the control element of said other portion of the multivibrator to adjust the free-running frequency thereof.
Claim 8
Dependent Claim
47 words
The scan generating circuit of claim 2 wherein said control potential varies exponentially with time and said synchronizing information is combined therewith to reach a conduction threshold, and means for changing the relative level of said control potential in accordance with the amplitude of the received signal.
Claim 9
Dependent Claim
48 words
The scan generating circuit of claim 7 in which the free-running frequency of said oscillator is established at a frequency which is less than the frequency of the scan-synchronizing information and the difference between the two frequencies is a direct function of the amplitude of the received signal.
Claim 10
Dependent Claim
31 words
The scan-generating circuit of claim 1 in which said receiver includes an automatic gain control circuit and the free-running frequency of the oscillator is varied in accordance with the output thereof.
References Cited (Backward Citations)
US3311701A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |