US3740489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Horizontal oscillator control for plural operating mode television receivers
Assignee: RCA Licensing Corp
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Filing: 1971-12-13
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Granted: 1973-06-19
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Expires: 1991-12-13
Abstract
Abstract A television receiver is disclosed which is capable of operating in any one of a plurality of modes. The receiver has circuitry enabling it to respond to a conventional radio frequency transmission in one mode. An external monitor mode is available by disabling the receiver''s front end processing circuitry and switching an input terminal of the receiver''s video amplifier to an output terminal of an external amplifier, whose bias is controlled by the receiver''s own keyed AGC circuit. The external biased controlled amplifier injects a signal into the receiver''s video amplifier of a magnitude comparable to the magnitude of a signal appearing in the video amplifier during a radio frequency transmission mode, enabling the receiver circuitry to perform substantially similar.
Inventors
- 👤 D Willis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:53
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/641; H04N5/00; H04N5/44; H04N5/445
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
221 words
In a television receiver of the type for responding to a composite television signal including luminance components, chrominance components and synchronizing pulse information components from different video signal sources having different characteristics of synchronizing information components, the combination comprising: a. a sync separator for separating said synchronizing pulse components from said composite television signal, b. an oscillator circuit for providing a signal having a repetition rate substantially equal to the repetition rate of said synchronizing pulse components, c. means coupled to said oscillator circuit and said sync separator for providing a control voltage which varies as a function of phase differences between said synchronizing pulses and said oscillator signal, d. a filter network coupled between said means and said oscillator circuit for applying said control voltage to said oscillator circuit to synchronize said oscillator signal to said synchronizing pulses, e. a frequency selective circuit coupled to said oscillator circuit for limiting the range of said oscillator circuit in maintaining synchronization to said control voltage, f. switching means having first and second states of operation, and g. means coupling said filter network and said frequency selective circuit to said switching means for changing the frequency response of said filter network and the range of said oscillator circuit when said switching means is activated from said first to said second state of operation.
Claim 2
Dependent Claim
221 words
In a television receiver of the type for responding to a composite television signal including luminance components, chrominance components and synchronizing pulse information components from different video signal sources having different characteristics of synchronizing information components, the combination comprising: a. a sync separator for separating said synchronizing pulse components from said composite television signal, b. an oscillator circuit for providing a signal having a repetition rate substantially equal to the repetition rate of said synchronizing pulse components, c. means coupled to said oscillator circuit and said sync separator for providing a control voltage which varies as a function of phase differences between said synchronizing pulses and said oscillator signal, d. a filter network coupled between said means and said oscillator circuit for applying said control voltage to said oscillator circuit to synchronize said oscillator signal to said synchronizing pulses, e. a frequency selective circuit coupled to said oscillator circuit for limiting the range of said oscillator circuit in maintaining synchronization to said control voltage, f. switching means having first and second states of operation, and g. means coupling said filter network and said frequency selective circuit to said switching means for changing the frequency response of said filter network and the range of said oscillator circuit when said switching means is activated from said first to said second state of operation.
Claim 3
Dependent Claim
38 words
The combination of claim 1 wherein said lastmentioned coupling means increases the frequency response of said filter network and increases the range of said oscillator circuit when said switching means is activated to said second state of operation.
Claim 4
Dependent Claim
65 words
The combination of claim 2 wherein said switching means is activated to said first state of operation when said television receiver is to respond to composite television signals fRom transmitted carrier video signal sources and wherein said switching means is activated to said second state of operation when said television receiver is to respond to composite television signals from a video tape recorder signal source.
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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |