Analog Devices,inc.

Fairchild Semiconductor Corporation

Willard Kraig Bucklen

Mehdi Hamidi Sani

De Dzwo Hsu

Display structures and methods are provided that introduce redundancy and use this redundancy with different mapping rules on different interleaved display lines to visually diffuse display artifacts. The artifacts are typically produced by errors in the transmission and recovery of analog display signals that subsequently drive digital displays. This visual diffusion substantially reduces the display artifacts and, because these visual improvements require only one element (an ADC) in the display system to be configured at a higher resolution, the visual advantageous are realized with relatively low cost.

Analog interface structures and methods that reduce display artifacts in digital displays

Analog-to-digital converters (ADCs) generally make code errors as they convert analog display signals to digital display signals of digital displays. Code-correction structures are provided that correct these code errors by initially configuring the ADCs to provide digital signals with redundant resolution. In particular, analog display signal having 2discrete analog levels are converted with M-bit ADCs wherein M exceeds N. This redundancy is utilized with a controller that distinguishes differences between an occurrence pattern of digital codes and a desired error-free pattern of digital codes. Subsequently, the controller corrects the digital code to reduce the observed differences.

Code-correction structures and methods for digital displays

Methods and structures are provided for generating a digital display signal in response to an analog display signal whose amplitude varies at a pixel rate and in response to a synchronization signal that defines spatial order for the analog display signal. The structures include a transform generator for providing a Fourier transform of the digital display signal and a transform analyzer which generates frequency and phase control signals in respective response to the frequency of an error spectral component and amplitudes of image spectral components in the transform. The frequency and control signals are applied to respectively adjust the sample rate of the sample clock and alter the phase of the sample clock.

Spectrally-adjusted sampling methods and structures for digital displays

Structures and methods are provided for generating a digital display signal from an analog signal that is limited to 2discrete analog levels and from a synchronization signal that defines spatial order for the digital display signal. These structures and methods accurately synchronize digitizers to the analog signal and they follow from a recognition that enhanced digitizer resolution will generate code patterns which easily distinguish between correct and incorrect sampling of the analog signals. Accordingly, the digitizers quantize the analog samples into an M-bit digital display signal wherein M exceeds N.

Analog interface structures and methods for digital displays

A VGA to analog video converter is useful e.g. for displaying video and/or graphics data from a computer onto a large screen television or television monitor. The RGB video signals output from the personal computer are first converted to digital form. The analog-to-digital converter which does this is clocked by a clock signal generated by a phase-locked loop using the horizontal synchronizing signal from the personal computer. The digital RGB signals are then converted to a YCbCR format. A flicker filter eliminates the flickering appearing on the TV monitor by operating on the luminance (Y) component. The YCbCr signals are encoded into NTSC or PAL Standard, and output in composite analog video or S-VHS format. A color subcarrier synthesizer generates the color subcarrier signal to generate an accurate subcarrier frequency for the video output signals. An analog-to-digital clock phase adjustment is used to ensure that the input RGB signals are sampled at the proper instant by the analog-to-digital converters.

Video signal converter for converting non-interlaced to composite video

Method for converting analog video signal to digital video signal

Method and apparatus for video flicker filter

A color subcarrier signal generator for use e.g, in a video converter measures the average error of the horizontal synchronizing signal frequency. The measured error is used as a compensator signal to control a direct digital synthesizer to generate a correct color subcarrier signal. The direct digital frequency synthesizer includes an address generator receiving the error signal and a look up table driven by the address generator.

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Greensboro, NC, United States of America

Willard Kraig Bucklen