US3711634A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chroma-burst separator and amplifier circuit
Assignee: Thomas International Corp
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Filing: 1971-10-18
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Granted: 1973-01-16
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Expires: 1991-10-18
Abstract
Abstract A combined separator/amplifier for deriving chroma and burst signals comprises a differential amplifier having a pair of differentially acting transistors coupled to a common current source. The current source is formed by a transistor driven by unseparated chroma and burst information from a composite color television signal. Bias networks force one differential transistor to be normally conductive and the other differential transistor to be normally nonconductive. An amplified chroma signal is available at the collector of the normally conductive transistor. During retrace, a single flyback pulse drives the differential transistors into their opposite conduction states, causing an amplified burst signal to be available at the collector of the normally nonconductive transistor. The circuit includes automatic chroma control and color killer action.
Inventors
- 👤 P Portoulas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:47
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/44; H04N9/455; H04N9/64; H04N9/70; H04N9/71
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
235 words
In a color television receiver for receiving a composite color television signal including a color reference burst signal and a chroma information signal, said burst signal and said chroma signal occurring at different points in time, a circuit for separating and amplifying both said burst signal and said chroma signal, comprising: a differential amplifier comprising a first amplifying means and a second amplifying means, each amplifying means having a first electrode, a second electrode, and an output electrode, means connecting in common said first electrodes, and means separately coupling the output electrodes of said first amplifying means and said second amplifying means to a source of operating potential; common means for coupling both said burst signal and said chroma signal to the commonly connected first electrodes of said first and second amplifying means; bias means for differentially biasing said amplifying means to cause said second amplifying means to conduct and said first amplifying means to be substantially nonconductive; and control means for coupling a control signal to one electrode of one of said amplifying means to cause said first amplifying means to conduct and said second amplifying means to be substantially nonconductive during the time when said color reference burst signal is present, whereby an amplified chroma signal is produced at the output electrode of said second amplifying means and an amplified burst signal is produced at the output electrode of said first amplifying means.
Claim 2
Dependent Claim
235 words
In a color television receiver for receiving a composite color television signal including a color reference burst signal and a chroma information signal, said burst signal and said chroma signal occurring at different points in time, a circuit for separating and amplifying both said burst signal and said chroma signal, comprising: a differential amplifier comprising a first amplifying means and a second amplifying means, each amplifying means having a first electrode, a second electrode, and an output electrode, means connecting in common said first electrodes, and means separately coupling the output electrodes of said first amplifying means and said second amplifying means to a source of operating potential; common means for coupling both said burst signal and said chroma signal to the commonly connected first electrodes of said first and second amplifying means; bias means for differentially biasing said amplifying means to cause said second amplifying means to conduct and said first amplifying means to be substantially nonconductive; and control means for coupling a control signal to one electrode of one of said amplifying means to cause said first amplifying means to conduct and said second amplifying means to be substantially nonconductive during the time when said color reference burst signal is present, whereby an amplified chroma signal is produced at the output electrode of said second amplifying means and an amplified burst signal is produced at the output electrode of said first amplifying means.
Claim 3
Dependent Claim
112 words
The circuit of claim 1 wherein said common means comprises a third amplifying means having a first electrode, a second electrode, and an output electrode, means coupling said output electrode of said third amplifying means to said commonly connected first electrodes of said first amplifying means and said second amplifying means, means coupling one of said first and second electrodes of said third amplifying means to a reference potential, and means coupling the other of said first and second electrodes of said third amplifying means to a source of said burst signal and said chroma signal, whereby said common means forms a common current source for said first and second amplifying means.
Claim 4
Dependent Claim
45 words
The circuit of claim 2 including ACC means for developing a control signal for automatic chroma control of the color television receiver, and means coupling said control signal to said third amplifying means to control the current flow therethrough in proportion to said control signal.
Claim 5
Dependent Claim
54 words
The circuit of claim 2 wherein said first amplifying means and said second amplifying means each comprise a transistor having emitter, base, and collector electrodes corresponding to said first, second, and output electrodes, respectively, said common connecting means and said bias means causing said transistors to form a common emitter driven, differential operating amplifier.
Claim 6
Dependent Claim
48 words
The circuit of claim 4 wherein said third amplifying means comprises a transistor having emitter, base and collector electrodes corresponding to said first, second and output electrodes, respectively, whereby the collector electrode of said third amplifying means drives the emitter electrodes of said first and second amplifying means.
Claim 7
Dependent Claim
51 words
The circuit of claim 1 including a source of color killer signal generated when the color television receiver is receiving a black-and-white transmission, and said bias means includes means responsive to said color killer signal for biasing the differential amplifying means to cause said second amplifying means to be substantially nonconductive.
Claim 8
Dependent Claim
39 words
The circuit of claim 6 wherein said second amplifying means includes a semiconductor junction, and said color killer signal responsive means couples said color killer signal to the semiconductor junction with a polarity to back bias the semiconductor junction.
Claim 9
Dependent Claim
64 words
The circuit of claim 1 including deflection and high voltage means in said color television receiver for generating a flyback pulse occurring when said color reference burst signal is present, and said control means couples the flyback pulse to one of the first and second amplifying means to cause said differential amplifier to switch conduction states, said flyback pulse corresponding to said control signal.
Claim 10
Dependent Claim
40 words
The circuit of claim 8 wherein said first amplifying means includes a semiconductor junction, and said control means couples said flyback pulse to the semiconductor junction of said first amplifying means with a polarity to forward bias said semiconductor junction.
References Cited (Backward Citations)
US3469022A
Cited
US3604843A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |