| Summary: | 碩士 === 國立交通大學 === 電子工程系 === 87 === In May 1998, Taiwan announced a formal decision on adopting the ATSC Digital Television (DTV) Standard as its local digital terrestrial broadcasting standard. An aggressive DTV broadcasting schedule was also being set. In order to define the DTV service area and specify the transmission parameters, we need to know the characteristics of the DTV signal over the irregular terrain, the impact of interference, and the relationship between the signal power and video quality.
There were two phases in this study. In phase I, we investigated the NTSC broadcasting signal characteristics over the VHF and the UHF channels. The objective is to identify their differences. In phase II, we measured the broadcasting DTV signal and compared the DTV service availability against the NTSC service availability. We selected 45 test sites for NTSC measurements and 88 test sites for DTV measurements, covering Taipei city and its vicinity (including Taipei, Tao-Yuan and Hsin-Chu). Test sites were chosen to include three types of environment: urban suburban and rural areas. The transmitter was located on the Chu-Zue Mountain in Taipei.
In general, the video quality of DTV is related to the field strength and the S/N. In addition, multipath impairments may result in transmission errors. Among the 45 test sites that both NTSC and DTV tested, DTV system is obviously much better than the NTSC system on video quality and service availability.
|
|---|
