Display control apparatus
First Claim
1. Display control apparatus for use with a CRT having an electron gun beam and an electron beam activated screen, x and y analog signal sources for providing, respectively, horizontal and vertical deflection of the electron beam, and having at least one CRT display control member, that improvement comprising:
- memory means for storing and addressing digital data;
first analog to digital converter means coupled between the x analog signal source and said memory means for converting the x analog deflection signal to a corresponding x digital deflection signal;
second analog to digital converter means coupled between the y analog signal source and said memory means for converting the y analog deflection signal to a corresponding y digital deflection signal;
sampling means coupled to said first and said second analog to digital converter means for simultaneously sampling each of the x and y digital signals, whereby an x, y digital sample set is provided from said first and said second analog to digital converter means;
each of said sample sets corresponding to a respective predetermined point location on the screen;
said point locations being spaced one from another over a predetermined portion of the entire viewed area of said screen;
said memory means for storing digital data relating to at least one CRT display control member for each of said digital sample sets;
said memory means for using said x, y digital sample sets to address said digital data;
digital to analog converter means coupled to said memory means for converting said addressed digital data to corresponding analog signals;
coupling means for coupling said digital to analog converter means to the display control member;
whereby each of said digital sample sets provides an address for respective digital data in said memory means to provide real time geometrically corrected analog signals to the display control member.
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Accused Products
Abstract
Horizontal and vertical deflection windings in a deflection yoke coil assembly of a CRT (cathode ray tube) having stroke written or raster scan displays are driven by x and y analog deflection signals, respectively. Each of the x and y analog deflection signals are converted to x and y digital signals, respectively, sampled to provide x, y sample sets which are coupled to a digital x correction signal memory and a digital y correction signal memory, respectively. Geometric corrections are stored in the memories for each of a predetermined number of x, y signal set values which correspond, respectively, to a number of point locations over the CRT screen. The x and y corrections that are addressed from the memories are supplied to MDACs (multiplying digital to analog converters) and then to analog delay line filters which supply the x, y analog correction signals for summing with the x, y analog deflection signals, respectively. The x and y digital signals are also coupled to separate astigmatism, dynamic focus, shading and convergence memories which are coupled to DACs (digital to analog converters) and then to respective CRT controls or associated circuitry.
24 Citations
15 Claims
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1. Display control apparatus for use with a CRT having an electron gun beam and an electron beam activated screen, x and y analog signal sources for providing, respectively, horizontal and vertical deflection of the electron beam, and having at least one CRT display control member, that improvement comprising:
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memory means for storing and addressing digital data; first analog to digital converter means coupled between the x analog signal source and said memory means for converting the x analog deflection signal to a corresponding x digital deflection signal; second analog to digital converter means coupled between the y analog signal source and said memory means for converting the y analog deflection signal to a corresponding y digital deflection signal; sampling means coupled to said first and said second analog to digital converter means for simultaneously sampling each of the x and y digital signals, whereby an x, y digital sample set is provided from said first and said second analog to digital converter means;
each of said sample sets corresponding to a respective predetermined point location on the screen;
said point locations being spaced one from another over a predetermined portion of the entire viewed area of said screen;said memory means for storing digital data relating to at least one CRT display control member for each of said digital sample sets;
said memory means for using said x, y digital sample sets to address said digital data;digital to analog converter means coupled to said memory means for converting said addressed digital data to corresponding analog signals; coupling means for coupling said digital to analog converter means to the display control member; whereby each of said digital sample sets provides an address for respective digital data in said memory means to provide real time geometrically corrected analog signals to the display control member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. Display control apparatus for use with a cathode ray tube having an electron gun beam and an electron beam activated screen and having horizontal and vertical deflection windings coupled to x and y analog deflection signal sources, respectively, that improvement comprising:
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first memory means for storing digital geometric corrections to the x deflection signal for each of a predetermined number of x, y signal sets, each x, y signal set corresponding to a respective predetermined geometrically correct point location on the screen; second memory means for storing digital geometric corrections to the y deflection signal for each of said predetermined number of x, y signal sets; first analog to digital converter means coupled between the x analog signal source and each of said first and second memory means and for converting the x analog deflection signal to an x digital deflection signal; second analog to digital converter means coupled between the y analog signal source and each of said first and second memory means and for converting the y analog deflection signal to a y digital deflection signal, so that an x digital correction signal is called from said first memory means for each x, y signal set and a y digital correction signal is called from said second memory means for each x, y signal set; first and second digital to analog converter means coupled to said first and second memory means, respectively, for converting the x and y digital correction signals for each of said predetermined number of x, y signal sets to x and y analog correction signals, respectively; first summing means coupled to said first digital to analog converter means and to the x analog signal source for summing said x analog correction signal to the x analog signal to provide a corrected x analog deflection signal; second summing means coupled to said second digital to analog converter means and to the y analog signal source for summing said y analog correction signal to the y analog signal to provide a corrected y analog deflection signal; whereby the x and y analog deflection signals are real time geometrically corrected to provide x and y analog signals to the x and y deflection windings respectively so that the x and y deflection windings will precisely position the electron gun beam at said respective predetermined geometrically correct point locations on the screen.
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Specification