一、前言卫星电视直接广播系统目前尚处于实验阶段,但是由于它具有一系列的优点,已显示出具有强大的生命力,各国都在迅速发展。卫星电视广播系统研制的最终目标是使一般家庭利用简单的接收设备能接收广播卫星所转发的电视信号,即个体接收方式,这种接收方式要求星卫转发器必须给出相当大的发射功 I. INTRODUCTION The satellite television direct broadcasting system is still in the experimental stage at present. However, because of its series of advantages, it has shown great vitality and all countries are developing rapidly. The ultimate goal of the development of satellite television broadcasting systems is to make the average family use simple receiving equipment to receive the television signals forwarded by the broadcasting satellites, that is, the individual receiving mode, which requires that the satellite guard transponder must give a considerable transmitting power