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CHROMA AMPLIFIER FOR A COLOR RECEIVER

  • US 3,586,765 A
  • Filed: 06/27/1969
  • Issued: 06/22/1971
  • Est. Priority Date: 06/27/1969
  • Status: Expired due to Term
First Claim
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1. A chroma amplifier and color-killer system for a color receiver for utilizing a chroma carrier signal modulated with color-image information and for further utilizing a control signal having amplitude variations which represent intensity variations of said chroma signal, which system comprises:

  • a cluster of three signal translating devices arranged in a Ytype circuit configuration to define a cascode amplifier including one of said devices connected in cascode with one of the remaining two devices and further to define a differential amplifier in which said one device is included in the signal paths of both of said remaining two devices;

    a second amplifier coupled in cascade with said cascode amplifier of said cluster and having a control circuit responsive to an applied killer signal for effectively disabling said second amplifier;

    means for applying said chroma signal to said cascode amplifier of said cluster and for deriving an amplified chroma signal from said second amplifier;

    means for applying said control signal to at least one of said remaining two devices of said cluster to control the amplification of said chroma signal;

    a color-killer circuit having an input and an output and responsive to a control potential applied to said input and exceeding a given threshold value for developing a killer signal at said output;

    means for connecting the input of said color killer to one of said remaining two devices of said cluster to receive therefrom a control potential exceeding said threshold level during operating intervals when the gain of the cascode amplifier of said cluster exceeds a preselected value; and

    means for connecting the output of said color killer to said control circuit of said second amplifier to interrupt translation of said chroma signal during said operating intervals.

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