US3558804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Agc circuit for a color television receiver
Assignee: US Philips Corp
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Filing: 1967-07-13
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Granted: 1971-01-26
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Expires: 1987-07-13
Abstract
Abstract A color television receiver has a color channel which includes two parallel signal paths and means for switching the signal paths so that the color information signals pass only one path and reference carrier signals pass only to other paths. The color signal path includes adjustable attenuator for adjusting the ratio between the color signals and reference signals. A control voltage derived from the reference signals is continuously applied to a controlled amplifier outside of the switched paths in order that the ratio is not affected by the control voltage.
Inventors
- 👤 Peter Johannes Hubertu Janssen
- 👤 Wilhelmus Martinus Mathijssen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:40
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/68
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
211 words
A color television amplitude control circuit for a composite video signal containing a luminance signal, a synchronization signal, a color information signal, and a color burst reference signal, said circuit comprising means for receiving said video signal and providing luminance, synchronization, color information, and color burst output signals; means for detecting said output synchronization signal coupled to said receiving means; a color channel having an input coupled to receive said information and burst output signal and an output, said channel comprising means for signal attenuating having an input coupled to said channel input and an output, alternative switching means coupled to said attenuation means for alternatively coupling said attenuation means to said color channel during the occurrence of said color information signal, means having an input coupled to said attenuation means output for linearly amplifying said color information and burst signals, and means coupled to said amplifying means for controlling the amplitude of both said burst and color information signals in said color channel by controlling the amplification of said amplifying means by the occurrence of said burst reference signal; means coupled to said detecting means for generating an enable signal from said detected synchronization signal; and means for applying said enable signal to said controlling means and said attenuation means.
Claim 2
Dependent Claim
211 words
A color television amplitude control circuit for a composite video signal containing a luminance signal, a synchronization signal, a color information signal, and a color burst reference signal, said circuit comprising means for receiving said video signal and providing luminance, synchronization, color information, and color burst output signals; means for detecting said output synchronization signal coupled to said receiving means; a color channel having an input coupled to receive said information and burst output signal and an output, said channel comprising means for signal attenuating having an input coupled to said channel input and an output, alternative switching means coupled to said attenuation means for alternatively coupling said attenuation means to said color channel during the occurrence of said color information signal, means having an input coupled to said attenuation means output for linearly amplifying said color information and burst signals, and means coupled to said amplifying means for controlling the amplitude of both said burst and color information signals in said color channel by controlling the amplification of said amplifying means by the occurrence of said burst reference signal; means coupled to said detecting means for generating an enable signal from said detected synchronization signal; and means for applying said enable signal to said controlling means and said attenuation means.
Claim 3
Dependent Claim
30 words
A circuit as claimed in claim 1 wherein said attenuation means comprises a diode reversed biased during the duration of said enable signal and forward biased during the remaining time.
Claim 4
Dependent Claim
40 words
A circuit as claimed in claim 2 further comprising a transistor amplifier coupled to receive said luminance and synchronization signal, and a potentiometer coupled to the emitter of said transistor amplifier and having a center tap coupled to said diode.
Claim 5
Dependent Claim
44 words
A circuit as claimed in claim 1 wherein said color channel further comprises first and second signal paths, said first path including said attenuation means, and means for combining the outputs of said signal paths coupled to the input of said linear amplifying means.
Claim 6
Dependent Claim
72 words
A circuit as claimed in claim 4 further comprising a transistor amplifier coupled to the output of said receiving means, a potentiometer coupled to the emitter of said transistor, said attenuation means comprising a tap on said potentiometer coupled to said first signal path, the emitter of said transistor being coupled to said second path, and said switching means comprising first and second gates coupled in said first and second paths respectively.
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) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |