| Summary: | 碩士 === 國立交通大學 === 電子工程系 === 89 === Digital TV (DTV) not only provides a better quality for video and audio services, it can also be used to carry other types of digital data. It will be one of the most important vehicles taking us to the information highway in the 21 century. However, it is different from the conventional TV in many aspects. In this thesis, we focus on the transmission characteristics of DTV and the content security issue. There are three parts in this thesis: (1) field test of ATSC DTV system for adjacent channel interference, (2) comparison of ATSC and DVB-T systems based on several sets of test data, and (3) digital watermarking for ownership protection of image/video data.
The reception ability under adjacent channel interference is an important test item particularly during the analog and digital TV co-existing period, because they may interfere each other. Based on the field test results, the DTV signal reception is almost the same with or without the adjacent channel interference. In measuring DTV interference to NTSC, when the lower adjacent channel DTV signal is transmitted, the average of NTSC C/N value drops about 4~5 dB, but it does not change the visual quality much.
There are several field tests around the world comparing two DTV systems, ATSC and DVB-T. due to different set-ups and parameters, these test results are not identical, but they show similar tendency. We did a comparison study and summarize our observations in this thesis.
Watermarking is a technique that embeds invisible data into multimedia material. It can be used for ownership authentication and identification. There are specific requirements when this technique in this thesis to demonstrate its usefulness. We also discuss the requirements and system architecture for watermark embedding in DTV.
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