US3575549A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hue control circuit
Assignee: Zenith Electronics LLC
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Filing: 1969-09-17
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Granted: 1971-04-20
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Expires: 1989-09-17
Abstract
Abstract A phase shifting network for changing the phase of the chrominance signal or the reference signal to adjust the hue content of the reproduced image in a color television receiver. The receiver includes a demodulator coupled to a source of chrominance signal and to a source of color reference signal. The phase shifting network comprises a signal translating circuit in the form of a transistor having a base input terminal and emitter and collector output terminals. The chrominance signal source is coupled to the base input terminal so that a first output signal is developed at the emitter and a second output signal, substantially opposite the phase to the first output signal, is developed at the collector. A phase shift circuit comprising a resistor and a tunable inductance varactor combination, in parallel, are coupled across the emitter and collector and respond to the output signals to derive a wave signal at the junction of the resistor and the inductance varactor combination. The effective reactance contributed by the varactor to the phase shift circuit is adjustable so as to permit a selective shift of the phase of the derived signal relative to the applied signal.
Inventors
- 👤 Charles F Hepner
- 👤 David L Zahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:43
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/643
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
230 words
In a color television receiver comprising means responsive to a composite color television signal, that includes a color subcarrier component modulated with chrominance information, for reconstituting a color image, which includes a demodulator coupled to a source of chrominance signal and to a source of color reference signal for developing a color control signal, a phase shifting network for changing the phase of one of said chrominance signal and said reference signal to adjust the hue content of said reconstituted image, said network comprising: a signal translating circuit having an input terminal and first and second output terminals; means for coupling one of said signal sources to said input terminal to apply a signal thereto and to develop first and second oppositely phased output signals at said first and second output terminals respectively; a phase shift circuit comprising a resistor and a reactance means coupled across said output terminals and responsive to said output signals for deriving a wave signal at the junction of said resistor and said reactance means; said reactance means comprising an inductance and a capacitor combination tunable near the frequency of said subcarrier; tuning means for changing the effective reactance contributed by said reactance means to said phase shift circuit to selectively shift the phase of said derived wave signal relative to said applied signal; and means for coupling said derived wave signal to said demodulator.
Claim 2
Dependent Claim
230 words
In a color television receiver comprising means responsive to a composite color television signal, that includes a color subcarrier component modulated with chrominance information, for reconstituting a color image, which includes a demodulator coupled to a source of chrominance signal and to a source of color reference signal for developing a color control signal, a phase shifting network for changing the phase of one of said chrominance signal and said reference signal to adjust the hue content of said reconstituted image, said network comprising: a signal translating circuit having an input terminal and first and second output terminals; means for coupling one of said signal sources to said input terminal to apply a signal thereto and to develop first and second oppositely phased output signals at said first and second output terminals respectively; a phase shift circuit comprising a resistor and a reactance means coupled across said output terminals and responsive to said output signals for deriving a wave signal at the junction of said resistor and said reactance means; said reactance means comprising an inductance and a capacitor combination tunable near the frequency of said subcarrier; tuning means for changing the effective reactance contributed by said reactance means to said phase shift circuit to selectively shift the phase of said derived wave signal relative to said applied signal; and means for coupling said derived wave signal to said demodulator.
Claim 3
Dependent Claim
20 words
A phase shifting network as set forth in claim 1 in which said signal translating circuit comprises a transistor device.
Claim 4
Dependent Claim
36 words
A phase shifting network as set forth in claim 2 in which said first output signal is developed at the emitter terminal of said transistor and said second output signal is developed at said collector terminal.
Claim 5
Dependent Claim
17 words
A phase shifting network as set forth in claim 1 in which said capacitor comprises a varactor.
Claim 6
Dependent Claim
24 words
A phase shifting network as set forth in claim 4 in which said tuning means comprises a DC biasing circuit coupled across said varactor.
Claim 7
Dependent Claim
27 words
A phase shifting network as set forth in claim 1 in which said phase shifting network is coupled between said source of chrominance signal and said demodulator.
Claim 8
Dependent Claim
41 words
A phase shifting network as set forth in claim 1 in which said phase shifting network is included in said source of color reference signal for shifting the phase of said color reference signal prior to its application to said demodulator.
Claim 9
Dependent Claim
39 words
A phase shifting network as set forth in claim 2 in which said inductance and said capacitor are coupled in parallel with each other and in series with said resistor between the emitter and collector terminals of said transistor.
Claim 10
Dependent Claim
33 words
A phase shifting network as set forth in claim 2 in which said inductance and said capacitor and said resistor are coupled in series across the emitter and collector terminals of said transistor.
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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |