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Method and device for preventing the jumping phenomenon of an OSD display region on a monitor screen

  • US 6,195,087 B1
  • Filed: 06/10/1998
  • Issued: 02/27/2001
  • Est. Priority Date: 02/06/1998
  • Status: Expired due to Fees
First Claim
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1. An apparatus for preventing the jumping phenomenon of an OSD display region on a monitor screen, the apparatus producing a clear signal to clear a counter for counting the number of scanning lines in the monitor screen according to a horizontal synchronizing signal and a vertical synchronizing signal, comprising:

  • a comparison circuit for producing a first clear reference signal according to the vertical synchronizing signal, and a selection signal according to a time difference between the front edge of a pulse of the horizontal synchronizing signal and the front edge of a corresponding pulse of the vertical synchronizing signal, the selection signal being set to a first logic state when the time difference is less than a fixed time period and to a second logic state when the time difference is greater than the fixed time period;

    a pulse generator for producing a second clear reference signal according to the vertical synchronizing signal, the second clear reference signal being delayed for a delay time period relative to the first clear reference signal; and

    a multiplexer for selecting one of the first clear reference signal received from the comparison circuit and the second clear reference signal received from the pulse generator as the clear signal according to the selection signal received from the comparison circuit, the first clear reference signal serving as the clear signal when the selection signal is in the first logic state and the second clear reference signal serving as the clear signal when the selection signal is in the second logic state.

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