The Design Of LED Large Screen Video Display System With Colour VGA Synchronous

LED Displaying Screen, as a new high technological product, is attached an important attention by mass. With the economical market rapidly developing, LED Displaying Screen has been widely used in industry,transport,business's advertisement,news release,physical match,war game simulating,electronic sight and other fields.The traditional LED Displaying system was put into practice by small or middle scale integrated circuit.The bulk of system is more large;the debugging is difficult; what is more, the system is not easy to modify.With the development of large scale integrated circuit and PLD. The capability of components have been improved a lot. PLD's hallmark are high integrated,high speed,high reliability ISP and so on. As a result, this design accomplishs the function of circuit, which not only can satisfy the high speed image data transmission of large screen system and improve the performance of circuit, but also increase the flexibility of circuit design. In the design, it is possible to act hardware description language procedure according to the practical application demand , instead of revising hardware design of the circuit, which reduce the design cycle and the cost.The system mainly has three parts of compositions: Video frequency gathering board, actuation board, display panel. The function of video frequency gathering board is to reveal the compound television signal from the computer to carry on A/D transforms, RGB separation processing and so on, output 24bits RGB signals and the synchronized signals .These functions were finished by video frequency decoding chip SAA7111 made by Philip corporation. The function of actuation board is to carry on the value filter and peaked processing for the numeral video signal, the enhancement quality of image displaying and save the video signal which has been processed to two groups of RAMs ,then in accordance with the structure of LED Displaying Screen and the characteristic of demonstration, it will read out data selectively and carry on the gradation pulse-duration modulation to give the display panel by the series monolithic integrated circuit EP1C6 of Altera corporation. The function of display panel is to carry on the data scanning for LED Displaying Screen and display a complete image under the controlling of the clock.It has completed the design of hardware circuit system and the related software in this design, and has made the significance exploration in the real-time imagery processing algorithm which was used in LED Displaying system.Finally ,it has carried on the analysis and the appraisal to the performance of LED Large Screen Displaying system. This system works under the PAL service pattern,and it's rate of field repetition is 50Hz.The frequency of image sampling is 27MHz; the size of image display is 512 by 64; the picture demonstration is clear and stable.