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Picture-in-picture circuitry using field rate synchronization

  • US 5,091,785 A
  • Filed: 04/20/1989
  • Issued: 02/25/1992
  • Est. Priority Date: 04/20/1989
  • Status: Expired due to Term
First Claim
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1. A television receiver having picture-in-picture capability, comprising:

  • an RF signal input for receiving a plurality of television RF signals;

    television tuner means for selecting a particular RF signal from said plurality of signals in response to a tuner control signal, and producing an IF signal from said selected RF signal;

    IF processing and detector means coupled to said tuner means for receiving said IF signal and producing a detected baseband video signal therefrom;

    control means coupled to said tuner means for generating said tuner control signal in response to data signals;

    data input means coupled to said control means for generating said data signals in response to activation by a user;

    a first auxiliary baseband video signal input terminal for receiving a first auxiliary baseband video signal;

    picture-in-picture processing means having a first signal input coupled to said video detector means for receiving said detected baseband video signal and a second signal input coupled to said first auxiliary baseband video input terminal means for receiving said baseband video signal, and combining said video signals to form a combined image signal which when displayed has a major portion, and has a minor portion displayed in a first position, said picture-in-picture processing means having a control input for receiving a second control signal from said control means, and having an output terminal for developing said combined image signal in response to said second control signal; and

    synchronizing means coupled to said output terminal of said picture-in-picture processing means for receiving said combined image signal and for generating a television vertical synchronizing component signal therefrom;

    said control means having an input for receiving said television vertical synchronizing component signal, said control means generating said second control signal in response to said data signals and in response to said television vertical synchronizing component signal to course said picture-in-picture processing means to form a combined image signal which when displayed has said minor portion displayed in a position offset from said first position by a predetermined step size in a desired direction, said predetermined step size being substantially smaller than the displayed height and width of said minor portion of said image.

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