VGA to NTSC converter and a method for converting VGA image to NTSC images
First Claim
1. A system for converting non-interlaced VGA image data to interlaced encoded image signals, the system comprising:
- means for detecting an identifiable mode of the non-interlaced VGA image data;
means for storing non-interlaced VGA image data as data within a plurality of field memory areas wherein pixel data from even numbered scan lines and pixel data from odd numbered scan lines are stored in separate field memory areas;
means for controlling operatively connected to the means for storing; and
means for filtering the data in the field memory areas so that pixel data from the field memory area storing even numbered scan lines, and pixel data from the field memory location storing odd numbered scan lines, are read alternately for each pixel in each output scan line so that reduced flicker interlaced encoded image signals are produced from the data within the field memory areas.
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Accused Products
Abstract
A system and a method are provided for conversion of a display of a computer monitor from VGA signals to NTSC signals for display on a television screen. The system implements a circuit which reduces flicker in the output of the NTSC screen. The system includes an input device for inputting a signal in an identifiable mode to stored non-interlaced data relating to the VGA image signals in field memory areas. The VGA image signals are converted in the field memory areas stored to interlaced NTSC image signals. A controller controls the storage and conversion of the VGA signals to NTSC image signals in field memory areas to produce an output.
34 Citations
23 Claims
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1. A system for converting non-interlaced VGA image data to interlaced encoded image signals, the system comprising:
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means for detecting an identifiable mode of the non-interlaced VGA image data; means for storing non-interlaced VGA image data as data within a plurality of field memory areas wherein pixel data from even numbered scan lines and pixel data from odd numbered scan lines are stored in separate field memory areas; means for controlling operatively connected to the means for storing; and means for filtering the data in the field memory areas so that pixel data from the field memory area storing even numbered scan lines, and pixel data from the field memory location storing odd numbered scan lines, are read alternately for each pixel in each output scan line so that reduced flicker interlaced encoded image signals are produced from the data within the field memory areas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for converting VGA image signals to NTSC image signals, the method comprising the steps of:
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storing non-interlaced VGA image data as data within field memory areas such that pixel data from even numbered scan lines and pixel data from odd numbered scan lines are stored in separate field memory areas; reading the data in the field memory areas to produce interlaced NTSC encoded image signals; filtering the pixel data within the field memory areas to reduce flicker within the interlaced NTSC encoded image signals by reading the pixel data from the field memory areas storing even numbered scan lines, and reading the pixel data from the field memory location storing odd numbered scan line pixel data, alternately for each pixel within the output scan lines; and controlling the storing and reading steps through circuitry configured by programmed instructions. - View Dependent Claims (11, 12, 13, 14)
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15. A circuit for controlling the reading of a frame buffer, the circuit comprising:
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an input means capable of controlling a switch by producing a signal; a multiplexer receiving the signal from the input means and producing a driving signal corresponding to either a filtered or unfiltered frame buffer read output enable command; a first inverter receiving the driving signal and producing an output; a pair of OR-gates each having a pair of inputs wherein one input of the first OR-gate receives the output of the first inverter and one input of the second OR gate receives the multiplexer driving signal; and a second inverter receiving a blanking signal and producing an output wherein the output is forwarded to a second input of each of the OR-gates wherein each of the OR-gates produces an output enable signal based on its inputs. - View Dependent Claims (16)
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17. A system for converting non-interlaced VGA image data into interlaced encoded image signals, the VGA non-interlaced data including pixel data for image frames containing both odd and even horizontal scan lines, the interlaced encoded image signals including first and second frames, the first frame containing pixel data for even scan lines and the second frame containing pixel data for odd scan lines, the system comprising:
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means for detecting an identifiable mode of the non-interlaced VGA image data, the detected mode determining the number of pixels in each scan line of said non-interlaced VGA image data; means for storing pixel data from even scan lines of said non-interlaced VGA image data in a first memory device; means for storing pixel data from odd scan lines of said non-interlaced VGA image data in a second memory device; and means for reading the pixel data stored in the first and second memory devices to generate said first and second frames of said interlaced encoded image signal. - View Dependent Claims (22, 23)
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18. A system for converting non-interlaced VGA image data to interlaced encoded image signals, the system comprising:
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means for storing non-interlaced VGA image data as data within field memory areas; means for controlling operatively connected to the means for storing; and means for filtering the data in the field memory areas, wherein the means for filtering alternately reads odd-numbered and even-numbered interlaced field memory areas for each pixel in the output scan lines, so that reduced flicker interlaced encoded image signals are produced from the data within the field memory areas.
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19. A system for converting non-interlaced VGA image data to interlaced encoded image signals, the system comprising:
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means for storing non-interlaced VGA image data as data within a plurality of field memory areas wherein pixel data from even numbered scan lines and pixel data from odd numbered scan lines are stored in separate field memory areas; means for controlling operatively connected to the means for storing; a memory storing instructions to output to the means for controlling wherein the instructions program the means for controlling; and means for filtering the data in the field memory areas so that pixel data from the field memory area storing even numbered scan lines, and pixel data from the field memory location storing odd numbered scan lines, are read alternately for each pixel in each output scan line so that reduced flicker interlaced encoded image signals are produced from the data within the field memory areas.
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20. A system for converting non-interlaced VGA image data to interlaced encoded image signals, the system comprising:
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means for storing non-interlaced VGA image data as data within field memory areas, wherein the means for storing includes a plurality of field buffer memory locations wherein pixel data from even numbered scan lines and pixel data from odd numbered scan lines are stored in separate field memory areas; means for controlling operatively connected to the means for storing; and means for filtering the data in the field memory areas so that pixel data from the field memory area storing even numbered scan lines, and pixel data from the field memory location storing odd numbered scan lines, are read alternately for each pixel in each output scan line so that reduced flicker interlaced encoded image signals are produced from the data within the field memory areas. - View Dependent Claims (21)
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Specification