Realization Of 3GSDI Character Inserter Based On IP Network Control

Character inserter is a kind of electronic equipment which can superimpose character on video signal.It is widely used in security,audio-visual and broadcasting fields,especially in remote mountainous areas where human activity is less,OSD system has played a very important role in the collection,classification and analysis of video content.Currently,most character inserters configuring in SDI camera can't overlap character flexibly for different resolution videos.On the other hand,the demand for HD video in 3GSDI signal formats grows rapidly in the security industry.Therefore,it is necessary to develop a kind of Character inserter which can handle 3GSDI signal.This paper reports a kind of 3GSDI character inserter based on IP Network Control.Using the FPGA+ARM model,the device realizes the goal of overlapping the vector characters on 3GSDI signal.User interface in server-side is written on the base of MQX operating system embedded in processor.Through the Ethernet connection,a remote visualization operation can be achieved by using the device.First,the technical background and development status of OSD are introduced in this paper.The working principle of the device is investigated and analyzed,which presents the design requirements for performance index of the device and gives the method for the design of device structure.In addition,the function of the device applied in both hardware and software sides is also introduced detailedly.Then,the required technologies during the design process such as high-speed digital signal balanced technology,digital signal integrity transmission technology,vector font fonts extraction,fonts fast fill technology,character signal to video signal overlay technology and HTTP webserver control technology have been discussed in detail.What's more,the technical problems such as the character signal overlying on the video signal in the circuit design,the maximum impedance matching of high speed digital signal pathways in PCB design,the minimum signal reflection and the arrangement of each digital signal path to minimize the interference between adjacent channels have been solved.Finally,the device is tested and the results show that the device reaches the predetermined performance target basically,and it possesses many advantages such as high integration,low failure rate and simple structure.