Automatic detection method for tuning the frequency and phase of display and apparatus using the method

Abstract

This invention relates to an automatic detection method and apparatus for tuning the frequency and phase of displaying clock of a display to match the frequency and phase of pixel clock of a PC's display interface card. Based on the synchronized displaying clock, the image shown by digital display will be stable and bright in color. The automatic detection apparatus of invention includes a clock generation unit, a sampling unit, a data processing unit, an accumulation unit, and a decision unit. The clock generation unit creates a plurality of sampling clocks and according to these sampling packet sequences, the sampling unit samples and holds the pixel signals of image frames based on the pixel clock of display interface card, and then stores these data in its registers. The data processing unit calculates and transmits the differences of sampled data based on every sampling clock to accumulation unit that accumulates these differences, and transmits the sums of these differences to decision unit that finds out the sampling clock with the smallest transmitted sum, and let the phase and frequency of sampling clock with the smallest summed value as those of displaying clock of the PC display.