System for overlaying a computer generated video signal on an NTSC video signal
First Claim
1. A system, operatively connected to a computer for providing a computer video signal, for overlaying the computer video signal on an NTSC video signal, comprising:
- first means for providing the NTSC video signal;
second means, operatively connected to said first means, for receiving the NTSC video signal and for generating a vertical reset signal and a horizontal start signal;
third means, operatively connected to said second means, for generating a clock control signal in dependence upon the horizontal start signal;
a clock, operatively connected to said third means, for generating a clock signal in dependence upon the clock control signal;
fourth means, operatively connected to said clock, said second means and the computer, for generating control signals for controlling the read out of the computer video signal by the computer, the control signals being generated in dependence upon the clock signal and the vertical reset signal;
fifth means, operatively connected to said first means and to the computer, for receiving the NTSC video signal and the computer video signal, and for generating a composite video signal.
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Accused Products
Abstract
A system for overlaying a computer generated video signal on an NTSC video signal includes horizontal and vertical pulse processor circuits for generating a horizontal start signal and a vertical reset signal, respectively, in accordance with NTSC standards, and a clocking system for receiving the vertical reset signal and the horizontal start signal and for generating control signals to control the read out of video data from the video generator of a computer so that it is read out at an NTSC rate. The system further includes a video insert keyer circuit for combining the NTSC video signal and the computer generated video signal and for generating a composite video signal for transmission to a monitor or standard television.
360 Citations
21 Claims
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1. A system, operatively connected to a computer for providing a computer video signal, for overlaying the computer video signal on an NTSC video signal, comprising:
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first means for providing the NTSC video signal; second means, operatively connected to said first means, for receiving the NTSC video signal and for generating a vertical reset signal and a horizontal start signal; third means, operatively connected to said second means, for generating a clock control signal in dependence upon the horizontal start signal; a clock, operatively connected to said third means, for generating a clock signal in dependence upon the clock control signal; fourth means, operatively connected to said clock, said second means and the computer, for generating control signals for controlling the read out of the computer video signal by the computer, the control signals being generated in dependence upon the clock signal and the vertical reset signal; fifth means, operatively connected to said first means and to the computer, for receiving the NTSC video signal and the computer video signal, and for generating a composite video signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system, operatively connected to a computer for generating a computer video signal, for overlaying the computer video signal on an NTSC video signal, comprising:
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first means for providing the NTSC video signal; second means, operatively connected to said first means and the computer, for receiving the NTSC video signal and the computer video signal and for generating a vertical reset signal, a horizontal start signal and a composite video signal; and third means, operatively connected to said second means and the computer, for receiving the vertical reset signal and the horizontal start signal and for generating control signals for controlling the rate at which the computer generates the computer video signal, so that the computer video signal is generated at the same rate as the NTSC video signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification