论文部分内容阅读
卫星技术自50年代开始,至今已经历了40多年。卫星的电视应用发生了质的变化和飞跃发展。最初,由于卫星技术、航天技术以及相关微波低噪声器件的局限性,卫星小而轻,一颗卫星只能搭载几个转发器,卫星有效全向辐射功率也很小,所以接收地面站的天线直径都在10m(米)以上,有的天线直径甚至达到20～30m,低噪声放大器也只能采用体积庞大的冷参放大器,因此,卫星的应用主要被局限于大站与大站之间进行电话、电报、电视节目的传输和中继。卫星对普通百姓来说,是相当遥远的高科技。短短的几十年,随着卫星技术、航天技术的飞速发展,卫星已从最初几十kg(千克)发展到如今的几千kg,越来越大的
Satellite technology has been in existence for more than 40 years since the 1950s. Satellite TV applications have undergone qualitative changes and rapid development. Initially, due to the limitations of satellite technology, space technology and related microwave low noise devices, the satellite is small and light, a satellite can only carry several transponders, and the effective radiated power of the satellite is also very small. Therefore, the receiving antenna of the ground station Diameter is more than 10m (meters), and some even reach 20 ~ 30m antenna diameter, low-noise amplifier can only use bulky cold amplifier, therefore, the satellite is mainly limited to the application of large stations and large stations Telephony, telegraph, transmission and relay of television programs. Satellite for the common people, is quite distant high-tech. In just a few decades, with the rapid development of satellite technology and space technology, the satellite has grown from the first tens of kilograms (kg) to several thousand kilograms nowadays, and more and more