NTSC receiver useable with Teletext/Viewdata information
First Claim
Patent Images
1. An NTSC television receiver capable of normally displaying approximately 200 horizontally lines of video information per field including;
- signal synthesis means for generating Teletext video information from coded digital signals received during the vertical intervals of normal television broadcast signals, said Teletext information having a format embracing approximately 240 horizontal scan lines per field; and
raster control means for altering the raster of said television receiver to display more than the normal number of horizontal lines and thereby enable direct use of said Teletext information.
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Accused Products
Abstract
A Teletext equipped NTSC television receiver system includes means for compressing the raster in the vertical direction in response to 625-line formatted Teletext signals to display normally overscanned horizontal lines on the television viewing screen. Thus 625-line formatted Teletext material may be used directly with NTSC receivers.
249 Citations
13 Claims
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1. An NTSC television receiver capable of normally displaying approximately 200 horizontally lines of video information per field including;
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signal synthesis means for generating Teletext video information from coded digital signals received during the vertical intervals of normal television broadcast signals, said Teletext information having a format embracing approximately 240 horizontal scan lines per field; and raster control means for altering the raster of said television receiver to display more than the normal number of horizontal lines and thereby enable direct use of said Teletext information. - View Dependent Claims (2, 3, 4)
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5. In combination in a television receiver:
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signal synthesis means capable of converting first digital signals obtained during the vertical intervals of normal NTSC 525 line television broadcast signals into a Teletext video display, said first digital signals having a format of approximately 200 usable horizontal scan lines per field; and means for making a Teletext display from second digital signals obtained during said vertical intervals, said second digital signals having a vertical format of approximately 240 horizontal scan lines per field, including raster control means for altering the receiver raster to enable display of the video corresponding to said second digital signals without alteration of said signal synthesis means. - View Dependent Claims (6, 7, 8)
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9. An NTSC television receiver capable of normally displaying approximately 200 horizontal lines of video information per field including:
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signal synthesis means for generating video information from coded audio digital signals, said video information having a format embracing approximately 240 horizontal scan lines per field; and raster control means for altering the raster of said television receiver to display more than the normal number of horizontal lines and thereby enable direct use of said video information. - View Dependent Claims (10, 11, 12)
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13. An NTSC television receiver capable of normally displaying approximately 200 horizontal lines of video information per field including:
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signal synthesis means for generating video information from coded digital signals, said video information having a format embracing approximately 240 horizontal scan lines per field; and raster control means for altering the raster of said television receiver to display more than the normal number of horizontal lines and thereby enable direct use of said video information by said television receiver.
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Specification