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1、国内外发展现状 目前,世界各先进国家的卫星电视接收站已进入家庭,已投入使用的卫星电视直播系统主要有日本BS卫星系统、英国OPTUS卫星系统、法国的TDF直播卫星系统、德国的TV—SAT系统以及美国的USDBS等十几个系统,覆盖了欧洲、日本、北美等国家和地区。随着卫星技术和图像编码压缩技术的发展,卫星直接广播电视已成为当前卫星广播电视发展的趋势。仅以美国而言,由于采用了图像数字编码压缩技术(压缩比约为50:1或90:1),一个带宽为27MHz、EIRP为48dBW的卫星转发器可传输4—8套电视节目,地面接收天线仅为0.45米。1993年美国休斯(HUGHES)公司发射了两颗USDBS卫星,每颗卫星装有16个转发器,每路转发器
1. Status Quo at Home and Abroad At present, the satellite television receiving stations of all the advanced countries in the world have entered the home. The satellite television broadcast systems that have been put into use mainly include the Japanese BS satellite system, the UK OPTUS satellite system, the French TDF direct broadcast satellite system, the German TV-SAT system and the United States more than a dozen systems USDBS, covering Europe, Japan, North America and other countries and regions. With the development of satellite technology and image coding compression technology, satellite direct broadcast television has become the current trend of satellite radio and television development. In the U.S. alone, a satellite transponder with 48-dBW EIRP and 27 MHz bandwidth achieves 4-8 television programs thanks to digital image compression (compression ratio of approximately 50: 1 or 90: 1) The receiving antenna is only 0.45 meters. 1993 HUGHES company launched two USDBS satellites, each satellite equipped with 16 transponders, each transponder