Video display system having multiple selectable screen formats

  • US 4,574,279 A
  • Filed: 11/03/1982
  • Issued: 03/04/1986
  • Est. Priority Date: 11/03/1982
  • Status: Expired due to Term
First Claim
Patent Images

1. A video display system responsive to mode select signals for displaying alphanumeric characters or graphic data in a display field of a video CRT screen having a height adjustment, the CRT operating from horizontal and vertical scan frequencies, the height of the display field determined by the screen format selected where the selected screen format includes a number of horizontal scan lines, the system including a means responsive, respectively, to first and second mode select signals for selecting a first screen format having a first number of horizontal scan lines and a second screen format having a second number of horizontal scan lines, where the height and width of the display field for both said first and second screen formats is the same, and where the first and second screen formats are generated, respectively, from first and second horizontal scan frequencies, said means adapted to generate said alphanumeric characters in either of said selected screen formats where said displayed characters are substantially identical in both said formats.

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