1.引言在广播电视中,中心台形成的全电视信号。在以电波形式传送到接收机以前,一般都要经过闭路或开路的长距离传输,经过一系列设备对信号进行这种或那种变换或处理。比如,从中心台到发射机房,通常就要经过一定距离 1. Introduction In radio and television, the center station formed a full TV signal. In the form of radio waves transmitted to the receiver before, usually through a closed circuit or open long-distance transmission, through a series of devices to signal one or the transformation or processing. For example, from the central station to the transmitter room, usually have to go through a certain distance