Study Of Relevant Technology For Digital Television And Development Of New Projection Display

In this paper, the principium and implement method of the digital television is described, and some key technology for the digital television is studied and emulated. After advantages and disadvantages of conventional algorithms for the motion compensation having been analyzed, a new fast search algorithm based on combining temporal dependence of video with spatial dependence of video is proposed, the emulated results shows that the coding efficiency and the PSNR of the decoded is improved greatly, meanwhile fast searching speed can be obtained. According to the features of the lastly hardware and software, fast DCT and fast IDCT algorithm should based on the decrease of sum of pluses and multiplies instead of the conventional decrease of the sum of multiplies only. A quantization algorithm of MPEG-2 video coding combing visual perception with the video avidity is presented, based on adaptive quantization algorithm proposed in TM5, the emulated result shows that the precision of the motive of the picture is high and the subjective quality of image is improved. The control method of channel buffer and the MPEG-2 audio and video synchronization model are studied also. Then the developed digital video broadcast-satellite (DVB-S) is described in detail. The performances of ATSC 8-VSB and DVB-T COFDM transmission system for Digital Television Terrestrial Broadcasting is compared, based on the most recent laboratory test results and theoretical analysis. In postprocessing techniques, a adaptive filter to decrease the blocking artifact is proposed, in this way, the decoded picture quality is improved. The presented error concealment algorithm has better performance. After contract ratio enhanced and edge sharpened for the picture, the quality of the picture is improved greatly. A high luminance and resolution YAG projection display, in which the developed YAG projection tube is implemented instead of the conventional projection CRT, has been developed. The convergence system, the key electronic circuit of the projection display, has been studied?in depth. Analog convergence system, digital- analog hybrid convergence system and full digital convergence system have been developed successively. The mathematic model for the digital convergence has been set up, and the characteristic matrix is defined, then a hybrid function interpolation is used in the developed digital convergence system to obtain fine convergence of less than 0.2%, this digital convergence system can adapt several picture modes. In the hardware of the convergence system, a full digital phase look loop without feedback circuit is presented. In the end, the features of the 48-inch YAG rear projection display and the 48- inch MAO rear projection display is described. The luminance is 1 lOOcdlm2and 2200cd/m2 respectively, and the horizontal resolution is 72OTVL and I 300TVL respectively. The performance of the 48-inch MAO rear projection display is streets ahead of that of the conventional CRT projection display.