| Digital Television (DTV) is the system used for transporting, receiving, processing, storing and controling digital TV signals. DTV will replace analog TV in next several years. The number of programs people can watch will be more than 4 times as before. As a result, people can get more information and enjoy themselves better. During this transition stage, STB (Set Top Box) holds the balance.Based on LSI 9700 STB solution, this dissertation studies theories related to DTV, including DVB teletext, DVB subtitle and STB's system software updated over the air, Solutions for those requirements are also supplied in this dissertation. The main contents are as follows:1. Discussions of the key techniques of DTV such as the system structure are included.Analysis of the system software architecture of LSI 9700 STB are also included in this dissertation.2. DVB teletext standards are studied in this dissertation.Teletext software decoder based on Vxworks is supplied, and it is used in LSI 9700 STB solution.The following is the main innovation of this decoder:1) A new Hash table is designed to store teletext pages, so people can access the wanted page immediately.2) An algorithm is designed to delete some teletext pages. The approach can update stored pages immediately and keep the dynamic RAM out of crash.3) Based on the principle of software structure designing, this decoder is easy to do system porting and expanding in future.3. DVB subtitle standards are studied in this dissertation, excellent data structure is designed to decode subtitle segment. A state machine is used to display subtitle smoothly.4. The design of software Loader system is introduced, including the principals, standards, key techniques and software development flow. |
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