笔者曾制作过一例利用同轴电缆分时传送广播和电视信号的电路实例。其原理是:制作一电路,利用音频信号的有、无加以延时处理后,去驱动控制电路,使之在有广播信号时把电缆端头与其有线前端设备断开的同时,自动把接头连接至扩音输出接口。而在电缆的末端却要求将端头接至两个串联的阻抗为32Ω的喇叭上。因为有线电视同轴电缆中的中间延长放大器采用交流60V串联供电,因而当没有广播信号时,应 I have produced an example of the use of coaxial cable to transmit broadcast and television signals on a time-sharing basis. The principle is: make a circuit, the use of audio signals, without delay processing, to drive the control circuit, so that there is a broadcast signal cable end with its cable front-end equipment is disconnected at the same time, automatically connect the connector To the PA output interface. At the end of the cable, however, it is required that the ends be connected to two series-connected speakers with an impedance of 32Ω. Because the cable extension cable in the middle of the coaxial cable AC 60V power supply in series, so when there is no broadcast signal should be