Control circuits for preventing kinescope color saturation during blooming

Claim 2

In a television receiver adapted to receive color television signal transmissions and having a gain controllable chroma amplifying channel responsive to color information components contained in said signal and for applying said information to a control electrode of a color kinescope, said receiver including deflection circuit means for said kinescope and means coupled to said deflection means for providing operating potentials for said kinescope and including other means coupled to said deflection circuit means for providing keying pulses, said keyIng pulses and operating potentials both being subjected to variations due to increasing load demands on said deflection circuit means, said variations in amplitude of said keying pulses further causing an undesired increase in the saturation of colors displayed by said kinescope, comprising therewith, a. first means coupled to said deflection circuit means for providing at an output terminal thereof a control signal having a level representative of said amplitude variations, b. second means coupling said first means to said chroma amplifying channel to decrease the gain of said channel in accordance with said control signal level, to maintain the amplitude of said color information components at a level to prevent undesired color saturation of said kinescope display during said increasing load demands.

Claim 3

In a television receiver adapted to receive color television signal transmission, and having a chroma channel responsive to color information components contained in said signals, said receiver including automatic color control means coupled to said chroma amplifier channel for varying the gain of said channel according to the amplitude of a burst signal provided by a burst separator circuit keyed by a pulse generated by deflection circuit means for a color kinescope also included in said receiver, said burst amplitude being undesirably dependent upon the amplitude of said keying pulse which amplitude is subject to variations due to increasing load requirements on said deflection circuit means, comprising therewith, a. first means coupled to said deflection circuit means for providing at an output terminal thereof a signal level representative of said amplitude variations, b. second means coupling said first means to said chroma channel for applying to said chroma channel a selected amplitude of said signal level, whereby the gain of said channel is affected substantially equal and opposite to that gain control afforded by said automatic color control means, to maintain the level of said color information components at a level to prevent undesired color saturation of said kinescope during said increasing load requirements.

Claim 4

In a television receiver adapted to receive color television signal transmission, and having a chroma channel responsive to color information components contained in said signals, said receiver including automatic color control means coupled to said chroma amplifier channel for varying the gain of said channel according to the amplitude of a burst signal provided by a burst separator circuit keyed by a pulse generated by deflection circuit means for a color kinescope also included in said receiver, said burst amplitude being undesirably dependent upon the amplitude of said keying pulse which amplitude is subject to variations due to increasing load requirements on said deflection circuit means, comprising therewith, a. first means coupled to said deflection circuit means for providing at an output terminal thereof a signal level representative of said amplitude variations, b. second means coupling said first means to said chroma channel for applying to said chroma channel a selected amplitude of said signal level, whereby the gain of said channel is affected substantially equal and opposite to that gain control afforded by said automatic color control means, to maintain the level of said color information components at a level to prevent undesired color saturation of said kinescope during said increasing load requirements.

Claim 5

In combination with a television receiver adapted to receive color television signal transmission, said receiver being of the type including deflection circuit means for a kinescope, a power recovery circuit including an inductance coupled to said deflection circuit means for increasing the efficiency of said deflection circuit means, means for providing keying pulses from said deflection circuit means and rectifying circuit means coupled to said deflection circuit means for producing operating potentials for said kinescope, said operating potentials and said keying pulses being subjected to amplitude variations when said load demands by said kinescope increase, said increasing load demands resulting in an increase of a voltage developed across said inductance included in said power recovery circuit, apparatus for automatic color control comprising, a. a keyed burst separator responsive to said color television signals for separating therefrom a burst signal included in said signals in response to the application to said separator of one of said keying pulses, said separated burst signal having an amplitude at least partly dependent upon said amplitude of said keying pulse, b. control means coupled to said burst separator for providing at an output a control signal proportional to said burst signal amplitude and therefore to the amplitude of color information in said television signal, c. means coupled between said control means and said inductance for applying to said control means said voltage across said inductance of a magnitude to substantially compensate said control signal for any variations therein due to said amplitude variations as affecting said keying pulses.

Claim 6

In combination with a television receiver adapted to receive color television signal transmission, said receiver being of the type including deflection circuit means for a kinescope, a power recovery circuit including an inductance coupled to said deflection circuit means for increasing the efficiency of said deflection circuit means, means for providing keying pulses from said deflection circuit means and rectifying circuit means coupled to said deflection circuit means for producing operating potentials for said kinescope, said operating potentials and said keying pulses being subjected to amplitude variations when said load demands by said kinescope increase, said increasing load demands resulting in an increase of a voltage developed across said inductance included in said power recovery circuit, apparatus for automatic color control comprising, a. a keyed burst separator responsive to said color television signals for separating therefrom a burst signal included in said signals in response to the application to said separator of one of said keying pulses, said separated burst signal having an amplitude at least partly dependent upon said amplitude of said keying pulse, b. control means coupled to said burst separator for providing at an output a control signal proportional to said burst signal amplitude and therefore to the amplitude of color information in said television signal, c. means coupled between said control means and said inductance for applying to said control means said voltage across said inductance of a magnitude to substantially compensate said control signal for any variations therein due to said amplitude variations as affecting said keying pulses.

Claim 7

Apparatus for automatic color control of a receiver adapted to receive color television signal transmissions, said receiver being of thE type including deflection control circuit means for a kinescope, means coupled to said deflection means for providing keying pulses during a retrace interval and for applying said pulses to a burst separator for retrieving and amplifying a burst signal contained in said color television signal transmission in accordance with the amplitude of said keying pulse, means coupled to said deflection means for providing operating potentials for said kinescope, said operating potentials and said keying pulses both subject to amplitude variations due to increasing load demands on said deflection control means, the combination therewith comprising, a. a chroma amplifier channel responsive to color information contained in said composite signal, b. control means coupled to said burst amplifier for providing a control voltage at an output terminal thereof proportional to the amplitude of said burst signal, said output terminal coupled to said chroma amplifier for varying the gain thereof according to said burst amplitude, c. circuit means coupled to said deflection means and responsive to said amplitude due to said increasing demands on said deflection circuit means, for providing a voltage signal having a magnitude in accordance with said amplitude variations, d. coupling means between said circuit means and said control means for applying at least a portion of said voltage signal to said control means to substantially compensate for such amplitude variations as affecting said control means and therefore said chroma amplifier, to maintain the amplitude of said color information components at a level to prevent undesired color saturation of said kinescope display during said increasing load demands.

Claim 8

Apparatus for automatic color control of a receiver adapted to receive color television signal transmissions, said receiver being of thE type including deflection control circuit means for a kinescope, means coupled to said deflection means for providing keying pulses during a retrace interval and for applying said pulses to a burst separator for retrieving and amplifying a burst signal contained in said color television signal transmission in accordance with the amplitude of said keying pulse, means coupled to said deflection means for providing operating potentials for said kinescope, said operating potentials and said keying pulses both subject to amplitude variations due to increasing load demands on said deflection control means, the combination therewith comprising, a. a chroma amplifier channel responsive to color information contained in said composite signal, b. control means coupled to said burst amplifier for providing a control voltage at an output terminal thereof proportional to the amplitude of said burst signal, said output terminal coupled to said chroma amplifier for varying the gain thereof according to said burst amplitude, c. circuit means coupled to said deflection means and responsive to said amplitude due to said increasing demands on said deflection circuit means, for providing a voltage signal having a magnitude in accordance with said amplitude variations, d. coupling means between said circuit means and said control means for applying at least a portion of said voltage signal to said control means to substantially compensate for such amplitude variations as affecting said control means and therefore said chroma amplifier, to maintain the amplitude of said color information components at a level to prevent undesired color saturation of said kinescope display during said increasing load demands.

Claim 9

An automatic color control circuit for receivers adapted to receive color television signal transmissions, said receiver being of the type including deflection control circuit means for a kinescope, comprising the combination of, a. first means for deriving operating potentials for said kinescope from said deflection control means, b. second means for deriving keying pulses, during a retrace interval from said deflection control means, said first and second means both being subjected to amplitude variations in response to varying load conditions on said deflection control means, c. a burst amplifier coupled to said second means and responsive to said color television signals for separating and amplifying from said color television signals a burst signal in accordance with the application thereto of one of said keying pulses, said amplification factor of said amplifier being proportional to the amplitude of said keying pulse, d. third means coupled to said burst amplifier for providing at an output thereof a control signal responsive to the amplitude of said burst signal, e. fourth means coupled to said first means and said third means responsive to said amplitude variations to provide at an output thereof a control signal having a magnitude at least in part due to said amplitude variations, when occurring, and as simultaneously affecting said first and second means, whereby any variation in said signal amplitude due to said variation in amplitude of said keying pulse is substantially compensated for at said output of said fourth means.

Claim 10

An automatic color control circuit for receivers adapted to receive color television signal transmissions, said receiver being of the type including deflection control circuit means for a kinescope, comprising the combination of, a. first means for deriving operating potentials for said kinescope from said deflection control means, b. second means for deriving keying pulses, during a retrace interval from said deflection control means, said first and second means both being subjected to amplitude variations in response to varying load conditions on said deflection control means, c. a burst amplifier coupled to said second means and responsive to said color television signals for separating and amplifying from said color television signals a burst signal in accordance with the application thereto of one of said keying pulses, said amplification factor of said amplifier being proportional to the amplitude of said keying pulse, d. third means coupled to said burst amplifier for providing at an output thereof a control signal responsive to the amplitude of said burst signal, e. fourth means coupled to said first means and said third means responsive to said amplitude variations to provide at an output thereof a control signal having a magnitude at least in part due to said amplitude variations, when occurring, and as simultaneously affecting said first and second means, whereby any variation in said signal amplitude due to said variation in amplitude of said keying pulse is substantially compensated for at said output of said fourth means.

Claim 11

The automatic color control circuit according to claim 5 wherein said third means comprises, a. an oscillator circuit including an active device having an input, output and a common terminal, b. means coupling said input terminal to said burst amplifier, said input terminal and said common terminal providing rectification of said burst signal to provide a DC level at said input terminal according to the amplitude of said burst signal.

Claim 12

The automatic color control circuit according to claim 6 wherein said fourth means comprises, a. a transistor arranged in a common base configuration and having an emitter electrode coupled to said input terminal of said active device in said osCillator circuit to provide a ground return path for said input terminal of said device, while further providing amplification of said DC level at said collector electrode, b. means coupled between said emitter electrode of said transistor and said deflection circuit means, for applying to said transistor a signal representative of said amplitude variations, c. a gain controllable chroma amplifier channel responsive to color information components contained in said color television signal transmissions, and d. means coupling said collector electrode of said transistor to said chroma amplifier channel to control the gain thereof in accordance with said control signal whose magnitude is at least in part due to said amplitude variations when occurring.

Claim 13

The automatic color control circuit according to claim 5 wherein, said first means further includes a power recovery circuit comprising, a. a unidirectional current carrying device coupled between said deflection means and a point of reference potential, b. filtering means coupled to said unidirectional device, including an inductor for developing a voltage thereacross during a retrace pulse generated by said deflection circuit means, said voltage amplitude being subjected to varying load conditions, c. a capacitor coupled between said inductance and said fourth means for applying at least a portion of said voltage to said fourth means.

Claim 14

In a television receiver adapted to receive color television signal transmissions, said receiver being of the type including deflection control circuit means for a kinescope, comprising the combination of, a. first means coupled to said deflection control means for deriving operating potentials for said kinescope, b. second means coupled to said deflection control means for deriving keying pulses during a retrace interval, said operating potentials and said keying pulses both being subjected to amplitude changes in response to varying load conditions on said deflection control means, c. a gain controllable chroma amplifier channel responsive to color information components contained in said color television signal transmissions, for applying said components to said kinescope and thereby affecting said load demands by said kinescope as supplied by said first means, d. a burst amplifier coupled to said second means and responsive to said color television signals for separating and amplifying a color burst signal included in said color television signals in accordance with the application thereto of one of said keying pulses, said amplification factor of said burst amplifier being proportional to the amplitude of said keying pulse, e. third means coupled to said burst separator for providing at an output terminal thereof a potential representative of the amplitude of said burst signal, f. a control circuit having an input and output terminal, said input terminal coupled to said output terminal of said third means and responsive coupled said potential to provide an amplified control voltage at said output terminal representative of the amplitude of said burst signal, for application of said control voltage to said chroma amplifier for controlling the gain thereof according to said control voltage, said control voltage undesirably serving to change said chroma amplifier gain in response to said amplitude variations as affecting said burst signal applied to said third means due to said varying load conditions, g. signal sensing means coupled to said first means responsive to said amplitude variations for providing a first sensing signal at an output thereof at least a portion of which is representative of said variations due to said increasing load conditions, h. means coupled between said signal sensing means and said burst amplifier for providing at an output terminal coupled to said input of said control circuit, a second sensing signal having a magnitude which is at a first predetermined value when said load condItions are such as to keep said amplitude variations within predetermined limits, and of a second value when said load conditions and therefore said amplitude variations exceed said value, said first value being of a magnitude to enable said control circuit to provide a control signal substantially according to said burst amplitude, and said second level being of a magnitude to enable said control circuit to provide said control signal according to said first and second sensing signals and in a direction to decrease said increasing load demands on said kinescope by decreasing the gain of said chroma amplifier, to maintain the level of said color information components at a level to prevent undesired color saturation of said kinescope during said increasing load requirements.

Claim 15

In a television receiver adapted to receive color television signal transmissions, said receiver being of the type including deflection control circuit means for a kinescope, comprising the combination of, a. first means coupled to said deflection control means for deriving operating potentials for said kinescope, b. second means coupled to said deflection control means for deriving keying pulses during a retrace interval, said operating potentials and said keying pulses both being subjected to amplitude changes in response to varying load conditions on said deflection control means, c. a gain controllable chroma amplifier channel responsive to color information components contained in said color television signal transmissions, for applying said components to said kinescope and thereby affecting said load demands by said kinescope as supplied by said first means, d. a burst amplifier coupled to said second means and responsive to said color television signals for separating and amplifying a color burst signal included in said color television signals in accordance with the application thereto of one of said keying pulses, said amplification factor of said burst amplifier being proportional to the amplitude of said keying pulse, e. third means coupled to said burst separator for providing at an output terminal thereof a potential representative of the amplitude of said burst signal, f. a control circuit having an input and output terminal, said input terminal coupled to said output terminal of said third means and responsive coupled said potential to provide an amplified control voltage at said output terminal representative of the amplitude of said burst signal, for application of said control voltage to said chroma amplifier for controlling the gain thereof according to said control voltage, said control voltage undesirably serving to change said chroma amplifier gain in response to said amplitude variations as affecting said burst signal applied to said third means due to said varying load conditions, g. signal sensing means coupled to said first means responsive to said amplitude variations for providing a first sensing signal at an output thereof at least a portion of which is representative of said variations due to said increasing load conditions, h. means coupled between said signal sensing means and said burst amplifier for providing at an output terminal coupled to said input of said control circuit, a second sensing signal having a magnitude which is at a first predetermined value when said load condItions are such as to keep said amplitude variations within predetermined limits, and of a second value when said load conditions and therefore said amplitude variations exceed said value, said first value being of a magnitude to enable said control circuit to provide a control signal substantially according to said burst amplitude, and said second level being of a magnitude to enable said control circuit to provide said control signal according to said first and second sensing signals and in a direction to decrease said increasing load demands on said kinescope by decreasing the gain of said chroma amplifier, to maintain the level of said color information components at a level to prevent undesired color saturation of said kinescope during said increasing load requirements.