US3842201A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Beam current limiter
Assignee: RCA Licensing Corp
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Filing: 1973-04-09
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Granted: 1974-10-15
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Expires: 1993-04-09
Abstract
Abstract Peak detection of a sampling voltage in the ground return path of the cathode ray tube anode supply voltage multiplier develops a relatively large control voltage for controlling cathode ray tube beam current. The large control voltage may be utilized directly to control the DC level of the video amplifier without resort to amplification. Less than unity gain coupling may be employed for greater circuit stability and insensitivity to temperature variation.
Inventors
- 👤 Maghami S Ghaem
- 👤 H Holshouser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:13
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/57; H04N5/59
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
123 words
In a television receiver having a video amplifier for applying video information to a cathode ray tube and voltage multiplier means to obtain an anode voltage supply for said cathode ray tube, cathode ray tube beam current limiting means comprising: means in series circuit with the ground return path of said multiplier means for developing a voltage proportional to cathode ray tube beam current, means for detecting the peak-to-peak amplitude of said voltage and responsive thereto to obtain a control voltage proportional to beam current, and control means responsive to said control voltage when said control voltage exceeds a predetermined amplitude to control the DC reference level of said video amplifier by applying a portion of said control voltage to said video amplifier.
Claim 2
Dependent Claim
123 words
In a television receiver having a video amplifier for applying video information to a cathode ray tube and voltage multiplier means to obtain an anode voltage supply for said cathode ray tube, cathode ray tube beam current limiting means comprising: means in series circuit with the ground return path of said multiplier means for developing a voltage proportional to cathode ray tube beam current, means for detecting the peak-to-peak amplitude of said voltage and responsive thereto to obtain a control voltage proportional to beam current, and control means responsive to said control voltage when said control voltage exceeds a predetermined amplitude to control the DC reference level of said video amplifier by applying a portion of said control voltage to said video amplifier.
Claim 3
Dependent Claim
47 words
The invention recited in claim 1 wherein said video amplifier includes a brightness control to establish the DC reference level of said video amplifier and said control means maintain a fixed voltage at said brightness control so long as said control voltage is below said predetermined amplitude.
Claim 4
Dependent Claim
38 words
The invention recited in claim 2 wherein said control means comprises an emitter follower amplifier to provide less than unity gain coupling of said control voltage to said brightness control when said control voltage exceeds said predetermined amplitude.
Claim 5
Dependent Claim
167 words
In a television receiver including a brightness control having a low level supply voltage for determining the brightness range of the picture displayed by the cathode ray tube of said receiver and voltage multiplying means to obtain a high voltage anode supply for said cathode ray tube, cathode ray tube beam current limiting means comprising: means in series circuit with the ground return path of said multiplier for developing a voltage proportional to beam current, means for detecting the peak-to-peak amplitude of said voltage and responsive thereto to obtain a DC control voltage proportional to beam current, said control voltage being large relative to said supply voltage, and control means responsive to said control voltage and coupled to said brightness control to maintain said supply voltage at said low level so long as said control voltage is below a predetermined level and applying a substantial portion of said control voltage to said brightness control when said control voltage exceeds said predetermined level to sharply limit picture brightness.
Claim 6
Dependent Claim
167 words
In a television receiver including a brightness control having a low level supply voltage for determining the brightness range of the picture displayed by the cathode ray tube of said receiver and voltage multiplying means to obtain a high voltage anode supply for said cathode ray tube, cathode ray tube beam current limiting means comprising: means in series circuit with the ground return path of said multiplier for developing a voltage proportional to beam current, means for detecting the peak-to-peak amplitude of said voltage and responsive thereto to obtain a DC control voltage proportional to beam current, said control voltage being large relative to said supply voltage, and control means responsive to said control voltage and coupled to said brightness control to maintain said supply voltage at said low level so long as said control voltage is below a predetermined level and applying a substantial portion of said control voltage to said brightness control when said control voltage exceeds said predetermined level to sharply limit picture brightness.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |