IC color demodulator with single external picture control

Claim 2

In a color television receiver having a source of composite video signal information and also a source of chroma signal information, an improved color demodulator arrangement, including in combination: a plurality of demodulators for deriving respective color signals; first amplifier means for amplifying the composite video signal and applying the same to first attenuator meanS for controlling the level of luminance signal as translated thereby; second amplifier means for amplifying the chroma signal and applying the same to a second attenuator means for controlling the level of chrominance signal as translated thereby; adjustable resistance means coupled to said first and second attenuators in common, the setting of which determines the level of luminance and chrominance signal information translated thereby simultaneously and in complimentary fashion; and black level clamping means for effecting a fixed bias to said demodulators in response to the blanking level of the composite video signal and regardless of the magnitude of the d-c component in said luminance signal as translated by said first attenuator means.

Claim 3

An improved color demodulator arrangement in accordance with claim 1 wherein said attenuators are in the form of current steering devices, each of which includes a pair of transistors connected in differential amplifier configuration and wherein said adjustable resistance means selectively steers said luminance signal and said chrominance signal through respective transistors of said differential amplifier current steering devices.

Claim 4

An improved color demodulator arrangement in accordance with claim 2 wherein each of said first and second amplifiers is in the form of an additional transistor amplifier having a base-input and a collector-output connected to the emitter junction point of a respective one of said differential amplifier current steering devices.

Claim 5

An improved color demodulator arrangement in accordance with claim 2 wherein said adjustable resistance means provides a manually selectable d-c bias to a respective transistor in each of said transistor pairs of said differential amplifier current steering devices.

Claim 6

An improved color demodulator arrangement in accordance with claim 1 wherein said black level clamping means includes a d-c blocking element at the output of said first amplifier and wherein said element is charged to a fixed, predetermined level during horizontal retrace interval in the composite video signal.

Claim 7

An improved color demodulator arrangement in accordance with claim 5 wherein said d-c blocking element is a capacitor interposed between the output of said first amplifier means and said plurality of demodulators, and wherein said capacitor is charged to said fixed d-c level by a further transistor having its collector-emitter circuit interconnected to a plane of reference potential through a serially connected resistance and pair of diodes, said last name transistor being driven into saturation during each horizontal retrace interval.

Claim 8

An improved color demodulator arrangement in accordance with claim 6 wherein the composite video signal at the output of said first amplifier means is a negative-going signal and wherein said further transistor is driven into conduction by a positive-going control signal in substantial time-coincidence with the horizontal retrace of interval said composite video signal.

Claim 9

An improved color demodulator arrangement in accordance with claim 1 wherein said plurality of demodulators, said first and second amplifier means, said attenuators and said black level clamping means are all disposed in a single integrated circuit and wherein said adjustable resistance means is provided as a separate external control thereto.

Claim 10

In a color television receiver having a source of composite video signal information and also a source of chroma signal information, an improved color demodulator arrangement, including in combination: a plurality of demodulators for deriving respective color signals; first amplifiers means for amplifying the composite video signal and applying the same to first attenuator means for controlling the level of luminance signal as translated thereby; second amplifier means for amplifying the chroma signal and applying the same to second attenuator means for controlling the level of chrominance signal as trAnslated thereby; manually adjustable resistance means for connection to said first and second attenuators in common so as to selectively and simultaneously control the level of luminance and chrominance signals as translated thereby; light dependent resistance means for connection to said first and second attenuators in common so as to control automatically the luminance and chrominance signal levels as translated thereby in accordance with and in response to ambient light level; and black level clamping means for effecting a fixed bias to said demodulators in response to the blanking level of the composite video signal and regardless of the magnitude of the d-c component in said luminance signal as translated by said first attenuator means.

Claim 11

In a color television receiver having a source of composite video signal information and also a source of chroma signal information, an improved color demodulator arrangement, including in combination: a plurality of demodulators for deriving respective color signals; first amplifiers means for amplifying the composite video signal and applying the same to first attenuator means for controlling the level of luminance signal as translated thereby; second amplifier means for amplifying the chroma signal and applying the same to second attenuator means for controlling the level of chrominance signal as trAnslated thereby; manually adjustable resistance means for connection to said first and second attenuators in common so as to selectively and simultaneously control the level of luminance and chrominance signals as translated thereby; light dependent resistance means for connection to said first and second attenuators in common so as to control automatically the luminance and chrominance signal levels as translated thereby in accordance with and in response to ambient light level; and black level clamping means for effecting a fixed bias to said demodulators in response to the blanking level of the composite video signal and regardless of the magnitude of the d-c component in said luminance signal as translated by said first attenuator means.

Claim 12

In a color television receiver having a source of composite video signal information and also a source of chroma signal information, an improved color demodulator arrangement, including in combination: a plurality of demodulators for deriving respective color signals; first amplifiers means for amplifying the composite video signal and applying the same to first attenuator means for controlling the level of luminance signal as translated thereby; second amplifier means for amplifying the chroma signal and applying the same to second attenuator means for controlling the level of chrominance signal as trAnslated thereby; manually adjustable resistance means for connection to said first and second attenuators in common so as to selectively and simultaneously control the level of luminance and chrominance signals as translated thereby; light dependent resistance means for connection to said first and second attenuators in common so as to control automatically the luminance and chrominance signal levels as translated thereby in accordance with and in response to ambient light level; and black level clamping means for effecting a fixed bias to said demodulators in response to the blanking level of the composite video signal and regardless of the magnitude of the d-c component in said luminance signal as translated by said first attenuator means.

Claim 13

In a color television receiver having a source of composite video signal information and also a source of chroma signal information, an improved color demodulator arrangement, including in combination: a plurality of demodulators for deriving respective color signals; first amplifiers means for amplifying the composite video signal and applying the same to first attenuator means for controlling the level of luminance signal as translated thereby; second amplifier means for amplifying the chroma signal and applying the same to second attenuator means for controlling the level of chrominance signal as trAnslated thereby; manually adjustable resistance means for connection to said first and second attenuators in common so as to selectively and simultaneously control the level of luminance and chrominance signals as translated thereby; light dependent resistance means for connection to said first and second attenuators in common so as to control automatically the luminance and chrominance signal levels as translated thereby in accordance with and in response to ambient light level; and black level clamping means for effecting a fixed bias to said demodulators in response to the blanking level of the composite video signal and regardless of the magnitude of the d-c component in said luminance signal as translated by said first attenuator means.

Claim 14

An improved color demodulator arrangement in accordance with claim 9 wherein switching means are included to selectively interconnect said manually adjustable resistance means and said light dependent resistance means to said first and second attenuators in common.

Claim 15

An improved color demodulator arrangement in accordance with claim 10 wherein said plurality of demodulators, said first and second amplifier means, said attenuators and said black level clamping means are all disposed in a single integrated circuit and wherein said manually adjustable resistance means, said light dependent resistance means and said switching means are provided as separate, external components thereto.

Claim 16

An improved black level clamping arrangement for a color television receiver having a source of composite video information comprised of an a-c component, and a d-c component, and further having a source of fly back pulse information at the horizontal frequency rate, said clamping arrangement including in combination; d-c blocking means at the output of said luminance amplifier for blocking the d-c component of the composite video while effectively passing the a-c component thereof; and means, including gating means, for receiving said horizontal fly back pulses and effecting a charge on said d-c blocking means at a fixed, predetermined d-c level during the horizontal retrace interval of the composite video signal information.

Claim 17

An improved black level clamping arrangement for a color television receiver having a source of composite video information comprised of an a-c component, and a d-c component, and further having a source of fly back pulse information at the horizontal frequency rate, said clamping arrangement including in combination; d-c blocking means at the output of said luminance amplifier for blocking the d-c component of the composite video while effectively passing the a-c component thereof; and means, including gating means, for receiving said horizontal fly back pulses and effecting a charge on said d-c blocking means at a fixed, predetermined d-c level during the horizontal retrace interval of the composite video signal information.

Claim 18

An improved black level clamping arrangement in accordance with claim 12 wherein said d-c blocking means is a capacitor, said gating means is a transistor and said means for charging said capacitor to said fixed d-c level comprises said transistor and further serially connected diode means and resistance means.

Claim 19

An improved black level clamping arrangement in accordance with claim 12 wherein the composite video at the output of said luminance amplifier is a negative-going signal and the horizontal fly back pulses applied to said gating means are positive-going pulses in substantial time-coincidence with the horizontal blanking portion of the composite video signal information.