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Broadcasting TV Industry is the cause of our many cause one of the fastest growing, including high-tech industry in the higher gold content is also an industry. As Communicate Industry, a worker engaged in satellite communications, is proud to flourish in our television industry as one of contemporary society, roles. At the same time between now many people are very concerned about some of the technology but do not quite understand, the author would like to briefly elaborate on the basic concept of satellite Digital TV Some core technology and DVB-S standard issue. The basic principles of satellite communications From the use of satellite can be divided into: resource exploration satellite, meteorological satellites, military satellites, communications satellites, broadcast satellites. In theory, if the earth over the equator relative to the geostationary satellite orbit 120 degrees to place three satellites each interval, we can achieve global communication or global broadcasting. Figure (1): Figure 1 Satellite TV Transmission is based on satellite communications developed, it is 35800km above the equator in the Earth's geostationary satellite office, loading the transponder and antenna system to broadcast terrestrial television signals transmitted directly to a large area radio and television coverage of a technology. It covers the area of the user directly to thousands of miles away to watch the other side of the earth and even radio and television programs. China has a vast, varied topography, population, and points Cloth And very uneven, if totally dependent on the traditional terrestrial wireless transmission solution to radio and television coverage is extremely difficult. The use of satellite transmission of radio and television programs, radio and television as a way to improve population coverage, improving the transmission quality of the most effective, most economical and most advanced means, in the past 10 years it has been rapid development and wide application. DVB Introduction DVB organization is a from 33 countries, 230 organizations participated in the international institutions, State Administration of Radio Canton ASTRI on April 13, 1999 as an association member to join the DVB organization. Also DVB (DigitalVideoBroadcasting) is the European Digital Video Broadcasting standard, the main criteria Package Including satellite TV DVB-S, Cable TV DVB-C, terrestrial broadcasting regular TV DVB-T and high-definition television (HDTV) broadcasting and transmission, these three transmission standard numbers were ETS300421, ETS300429 and ETS300744? ETS Europe Telecommunications Standards?. DVB-S is to change the standard analog TV technology for the formation of separate different situation, so as to formulate a set of Digital Broadcasting Technical specifications, it has contributed to their becoming responsible for digital broadcasting technology, international standards, and promote international exchange radio and television technology, cooperation and development tasks. DVB project's main objective is to find a transmission media are applicable to all digital television technologies and systems. Its requirements are: 1, the flexibility to transmit MPEG-2 video, audio and other data signals. 2, MPEG-2 uses a unified transmission bit stream multiplexing. 3, using uniform Service Information system provides detailed information such as radio programs. 4, a uniform level of Reed - Solomon forward error correction system. 5, scrambling to use a unified system, but may have different encryption methods. 6, selected for different transmission media, modulation and channel coding as well as any necessary additional error correction method. 7, to encourage use outside the European DVB standard, promote the establishment of a worldwide digital video broadcasting standards. 8, support the digital system teletext system. DVB-S system, the core technology DVB technology is the core of the system General MPEG-2 video and audio coding, now mainly used in digital satellite and television broadcasting is the MP @ ML. The first generation of European DVB receiver will provide up to 625 lines Studio Quality? ITU-Rec, BT601? Images? ITU is the ITU?, Can be 4:3 or 16:9 aspect ratio. Based on business requirements can also be used to determine rate. In general, the higher the selected bit rate, image quality is better, but take up more band width. Rate of use and image content has a lot for the sport more images such as sports programs can use a higher bit rate, for cartoons and other programs can use a lower bit rate. Therefore, the current number of programs in the bit stream into a bit stream complex cases, with statistical multiplexing method, the program at different bit-rate flexibility to allocate between the number of total bit rate. In order to meet the requirements of various types of material, ITU-Rec, BT601 digital studio quality required for the 9Mbit / s, PAL / SECAM, broadcast quality digital rate required 5Mbit / s, as with the MPEG-2 transport stream is a bit kind of packet structure, so you can easily add appropriate information to a variety of services, such as images, sound and data services, and together, and the format of service information for the detailed requirements for the formation of the standard is to serve the information Standard ETS300468. DVB system uses a low data rate of MPEG-1 Layer II audio standards as generic audio compression coding standard, in order to get close to CD quality sound. DVB-S standard describes the system for satellite transmission of digital multi-frame structure, channel coding and modulation. Uplink in the satellite transmission system block diagram of the signal processes and the organization as follows: I am an expert from skeletonmechanicalwatch.com, while we provides the quality product, such as China automatic skeleton watch , ladies skeleton watch, skeleton mechanical watch,and more.
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